Chlorophyll-a(Chl-a)concentration is a primary indicator for marine environmental monitoring.The spatio-temporal variations of sea surface Chl-a concentration in the Yellow Sea(YS)and the East China Sea(ECS)in 2001-20...Chlorophyll-a(Chl-a)concentration is a primary indicator for marine environmental monitoring.The spatio-temporal variations of sea surface Chl-a concentration in the Yellow Sea(YS)and the East China Sea(ECS)in 2001-2020 were investigated by reconstructing the MODIS Level 3 products with the data interpolation empirical orthogonal function(DINEOF)method.The reconstructed results by interpolating the combined MODIS daily+8-day datasets were found better than those merely by interpolating daily or 8-day data.Chl-a concentration in the YS and the ECS reached its maximum in spring,with blooms occurring,decreased in summer and autumn,and increased in late autumn and early winter.By performing empirical orthogonal function(EOF)decomposition of the reconstructed data fields and correlation analysis with several potential environmental factors,we found that the sea surface temperature(SST)plays a significant role in the seasonal variation of Chl a,especially during spring and summer.The increase of SST in spring and the upper-layer nutrients mixed up during the last winter might favor the occurrence of spring blooms.The high sea surface temperature(SST)throughout the summer would strengthen the vertical stratification and prevent nutrients supply from deep water,resulting in low surface Chl-a concentrations.The sea surface Chl-a concentration in the YS was found decreased significantly from 2012 to 2020,which was possibly related to the Pacific Decadal Oscillation(PDO).展开更多
Tea pigments have significant effects on human health.However,more attention have been paid to their physiological functions.The aim of this study was to analyze the quantitative and qualitative impact of tea pigments...Tea pigments have significant effects on human health.However,more attention have been paid to their physiological functions.The aim of this study was to analyze the quantitative and qualitative impact of tea pigments on human health,together with their current and potential future research directions.The study searched and screened 520 publications on WOS from January 2002 to December 2022.The article collected and collated literature published in the last 20 years and analyzed it bibliometrically for years,journals,countries,authors,topics,keywords and strongest citation bursts.The findings of keywords and strongest citation bursts revealed that the most discussed research topics were anticancer,black tea polyphenol,antioxidant,activator inhibitor,in vivo,gut microbiota,and summarize the relevant literature.As a reference for future research,the literature pointed out current shortcomings and speculated future development trend of tea pigments.展开更多
Heavy metal contamination is one of the most important abiotic stresses affecting physiological activities of plants.We investigated the effects of cadmium(Cd) and lead(Pb) on chlorophyll fluorescence(Fv/Fm,Fo,an...Heavy metal contamination is one of the most important abiotic stresses affecting physiological activities of plants.We investigated the effects of cadmium(Cd) and lead(Pb) on chlorophyll fluorescence(Fv/Fm,Fo,and Fm),photosynthetic pigments(chlorophyll a and b),and proline in one-year-old seedlings of Robinia pseudoacacia.The seedlings were treated twice over a period of 10 days with Cd and Pb at concentrations of 0,250,500,1000 and2000 mg L-1.Saline solution containing Cd and Pb was sprayed on the leaves.Chlorophyll and proline contents were measured after 10 days.Chlorophyll fluorescence of R.pseudoacacia was affected slightly by high concentrations(1000,2000 mg L-1) of Cd and Pb.Chlorophyll a and a/b increased at 1000 and 2000 mg L-1of Cd and proline content of leaves was similar in all treatments of Cd and Pb.Our results indicated that photosynthetic sensitivity of R.pseudoacacia to Cd and Pb contamination was weak.Photosystem II chlorophyll pigments were not damaged by Pb and Cd stress.We conclude that chlorophyll fluorescence along with chlorophyll and proline contents are useful indicators of Cd and Pb stresses in R.pseudoacacia which widely planted in urban polluted regions in Iran.展开更多
For plants growing in parks and along the roadsides of a city, the environmental and seasonal regulation of growth, or photosynthesis, is seldom assessed. The phenology of plants may differ due to varying environments...For plants growing in parks and along the roadsides of a city, the environmental and seasonal regulation of growth, or photosynthesis, is seldom assessed. The phenology of plants may differ due to varying environments, which may result in different growth or adaptability to local environments. Therefore, we explored several assays and optical indicators of photosynthesis and stress in three tree species (Prunus yedoensis Matsum, Zelkova serrata Makino and Acer palmatum Thunb. ) and two herbaceous species (Artemisia princeps Pamp and Taraxacum officinale Weber)growing commonly in three local parks of Changwon city, a large industrial city in Korea. The photochemical reflectance index (PRI), chlorophyll fluorescence, and pigments including chlorophyll and the flavonoids of leaves were monitored over a growing season for two years to evaluate the adaptability of plants to local environments. The values of all measurements exhibited striking seasonal and regional changes. PRI values were closely timed with photosynthetic activity and the pigment formation of leaves, particularly in some tree species. For the tree species, the plants which had the low values of PRI during the active growing season showed low levels of both chlorophyll fluorescence and high level of flavonoid, indicating that these plants were experiencing low photosynthetic activity and the specific needs in growth and development were not sufficiently provided by the local environment. Our results indicate that PRI provided a clear optical indicator of plant adaptability to the local environment and may provide a useful metric of effective growth using remote sensing measurements. Furthermore, the periodic PRI measurement is encouraged to be included in the surveillance program for city plant management.展开更多
Pigments present in the brown-greenish C morph of an intracellular endosymbiont of Pomacea canaliculata were investigated.Acetone extracts of the endosymbiotic corpuscles showed an absorption spectrum similar to that ...Pigments present in the brown-greenish C morph of an intracellular endosymbiont of Pomacea canaliculata were investigated.Acetone extracts of the endosymbiotic corpuscles showed an absorption spectrum similar to that of chlorophylls.Three fractions obtained from silica gel column chromatography of the acetone extracts(CI,CII and CIII),were studied by positive ion fast atom bombardment-mass spectrometry(FAB–MS)and hydrogen-nuclear magnetic resonance(H-NMR).Results indicated the presence of(1)a sterol in the yellow colored CI fraction;(2)a mixture of pheophorbides a and b in the major green fraction,CII;and(3)a modified pheophorbide a in the smaller green fraction,CIII.Aqueous extracts of the C endosymbiont did not show evidence of the occurrence of C-phycocyanin,allophycocyanin or phycoerithrin(light absorption,fluorescence emission,and electrophoresis of the protein moieties)while cyanobacterial cells(Nostoc sp.)showed evidence of C-phycocyanin and allophycocyanin.The possible phylogenetic and functional significance of the pigments present in the C endosymbiont is discussed.展开更多
Flavonoids are critical secondary metabolites that determine the health benefits and flavor of tea,while chlorophylls are important contributors to the appearance of tea.However,transcription factors(TFs)that can inte...Flavonoids are critical secondary metabolites that determine the health benefits and flavor of tea,while chlorophylls are important contributors to the appearance of tea.However,transcription factors(TFs)that can integrate both chlorophyll biosynthesis and flavonoid accumulation in response to specific light signals are rarely identified.In this study,we report that the GOLDEN 2-LIKE TF pair,CsGLK1 and CsGLK2,orchestrate UV-B-induced responses in the chlorophyll biosynthesis and flavonoid accumulation of tea leaves.The absence of solar UV-B reduced the transcriptional expression of CsGLKs in the tea leaves and was highly correlated with a decrease in flavonoid levels(especially flavonol glycosides)and the expression of genes and TFs involved in chlorophyll biosynthesis and flavonoid accumulation.In vivo and in vitro molecular analyses showed that CsGLKs could be regulated by the UV-B signal mediator CsHY5,and could directly bind to the promoters of gene and TF involved in light-harvesting(CsLhcb),chlorophyll biosynthesis(CsCHLH,CsHEMA1,and CsPORA),and flavonoid accumulation(CsMYB12,CsFLSa,CsDFRa,and CsLARa),eventually leading to UV-B-induced responses in the chlorophylls and flavonoids of tea leaves.Furthermore,UV-B exposure increased the levels of total flavonoids,CsGLK1 protein,and expression of CsGLKs and target genes in the tea leaves.These results indicate that CsGLKs may modulate tea leaf characteristics by regulating chlorophyll biosynthesis and flavonoid accumulation in response to solar UV-B.As the first report on UV-B-induced changes in flavonoid and chlorophyll regulation mediated by CsGLKs,this study improves our understanding of the environmental regulations regarding tea quality and sheds new light on UV-B-induced flavonoid responses in higher plants.展开更多
Chlorophyll (Chl) content,especially Chl b content,and stomatal conductance (G_s) are the key factors affecting the net photosynthetic rate (P_n).Setaria italica,a diploid C_4 panicoid species with a simple genome and...Chlorophyll (Chl) content,especially Chl b content,and stomatal conductance (G_s) are the key factors affecting the net photosynthetic rate (P_n).Setaria italica,a diploid C_4 panicoid species with a simple genome and high transformation efficiency,has been widely accepted as a model in photosynthesis and drought-tolerance research.The current study characterized Chl content,G_s,and P_n of 48 Setaria mutants induced by ethyl methanesulfonate.A total of 24,34,and 35 mutants had significant variations in Chl content,G_s,and P_n,respectively.Correlation analysis showed a positive correlation between increased G_s and increased P_n,and a weak correlation between decreased Chl b content and decreased P_n was also found.Remarkably,two mutants behaved with significantly decreased Chl b content but increased P_n compared to Yugu 1.Seven mutants behaved with significantly decreased G_s but did not decrease P_(n )compared to Yugu 1.The current study thus identified various genetic lines,further exploration of which would be beneficial to elucidate the relationship between Chl content,G_s,and P_n and the mechanism underlying why C_4 species are efficient at photosynthesis and water saving.展开更多
Salinity is one of the major abiotic factors that limit the growth and productivity of plants.Foliar application of plant growth regulators(PGRs)may help plants ameliorate the negative impacts of salinity.Thus,a field...Salinity is one of the major abiotic factors that limit the growth and productivity of plants.Foliar application of plant growth regulators(PGRs)may help plants ameliorate the negative impacts of salinity.Thus,a field experiment was conducted at the Botanical Garden University of Balochistan,Quetta,to explore the potential role of PGRs,i.e.,moringa leaf extract(MLE;10%),proline(PRO;1μM),salicylic acid(SA;250μM),and thiourea(TU;10 mM)in ameliorating the impacts of salinity(120 mM)on Plantago ovata,an important medicinal plant.Salinity hampered plant photosynthetic pigments and metabolites but elevated oxidative parameters.However,foliar application of PGRs enhanced photosynthetic pigments,including Chl b(21.11%),carotenoids(57.87%)except Chl a,activated the defense mechanisms by restoring and enhancing the metabolites,i.e.,soluble sugars(49.68%),soluble phenolics(33.34%),and proline(31.47%),significantly under salinity stress.Furthermore,foliar supplementation of PGRs under salt stress led to a decrease of about 43.02%and 43.27%in hydrogen peroxide and malondialdehyde content,respectively.Thus,PGRs can be recommended for improved photosynthetic efficiency and metabolite content that can help to get better yield under salt stress,with the best and most effective treatments being those of PRO and MLE to predominately ameliorate the harsh impacts of salinity.展开更多
Chlorophyll contributes to tea coloration, which is an important factor in tea quality. Chlorophyll metabolism is induced by light, but the transcriptional regulation responsible for light-induced chlorophyll metaboli...Chlorophyll contributes to tea coloration, which is an important factor in tea quality. Chlorophyll metabolism is induced by light, but the transcriptional regulation responsible for light-induced chlorophyll metabolism is largely unknown in tea leaves. Here, we characterized a chlorophyllase1 gene CsCLH1 from young tea leaves and showed it is essential for chlorophyll metabolism, using transient overexpression and silencing in tea leaves and ectopic overexpression in Arabidopsis. CsCLH1 was significantly induced by high light. The DOF protein CsDOF3, an upstream direct regulator of CsCLH1, was also identified. Acting as a nuclear-localized transcriptional factor, CsDOF3 responded for light and repressed CsCLH1 transcription and increased chlorophyll content by directly binding to the AAAG cis-element in the CsCLH1 promoter. CsDOF3was able to physically interact with the R2R3-MYB transcription factor CsMYB308 and interfere with transcriptional activity of CsCLH1. In addition, CsMYB308 binds to the CsCLH1 promoter to enhance CsCLH1 expression and decrease chlorophyll content. CsMYB308 and CsDOF3 act as an antagonistic complex to regulate CsCLH1 transcription and chlorophyll in young leaves. Collectively, the study adds to the understanding of the transcriptional regulation of chlorophyll in tea leaves in response to light and provides a basis for improving the appearance of tea.展开更多
Upwelling occurs on the coast of Java between June and October, forced by local alongshore winds associated with the southeasterly monsoon. This causes variations in phytoplankton community composition in the upwellin...Upwelling occurs on the coast of Java between June and October, forced by local alongshore winds associated with the southeasterly monsoon. This causes variations in phytoplankton community composition in the upwelling zone compared with the surrounding offshore area. Based on pigments analysis with subsequent calculations of group contributions to total chlorophyll a(Chl a) using CHEMTAX, we studied the distribution and composition of phytoplankton assemblages in the subsurface chlorophyll maximum along the south coast of Java and the influence of upwelling. Nineteen phytoplankton pigments were identified using high-performance liquid chromatography, and CHEMTAX analysis associated these to ten major phytoplankton groups. The phytoplankton community in the coastal area influenced by upwelling was characterized by high Chl a and fucoxanthin concentrations, indicating the dominance of diatoms. In contrast, in the offshore area, the Chl a and fucoxanthin concentrations declined to very low levels and the community was dominated by haptophytes represented by 19′-Hexanoyloxyfucoxanthin. Accordingly, microphytoplankton was found to be the major size class in the coastal area influenced by upwelling, while nanophytoplankton was most abundant in the offshore area. Low concentrations of other accessory pigments indicated less contribution from dinoflagellates,prasinophytes, chlorophytes and cryptophytes. Photo-pigment indices revealed that photosynthetic carotenoids(PSCs) were the largest component of the pigment pool, exceeding the proportion of Chl a, with the average PSCTP up to 0.62. These distribution trends can mainly be explained by phytoplankton adaption strategies to upwelling and subsurface conditions by changing species composition and adjusting the pigment pool.展开更多
Biochemical components of Moso bamboo(Phyllostachys pubescens)are critical to physiological and ecological processes and play an important role in the material and energy cycles of the ecosystem.The coupled PROSPECT w...Biochemical components of Moso bamboo(Phyllostachys pubescens)are critical to physiological and ecological processes and play an important role in the material and energy cycles of the ecosystem.The coupled PROSPECT with SAIL(PROSAIL)radiative transfer model is widely used for vegetation biochemical component content inversion.However,the presence of leaf-eating pests,such as Pantana phyllostachysae Chao(PPC),weakens the performance of the model for estimating biochemical components of Moso bamboo and thus must be considered.Therefore,this study considered pest-induced stress signals associated with Sentinel-2A/B images and field data and established multiple sets of biochemical canopy reflectance look-up tables(LUTs)based on the PROSAIL framework by setting different parameter ranges according to infestation levels.Quantitative inversions of leaf area index(LAI),leaf chlorophyll content(LCC),and leaf equivalent water thickness(LEWT)were derived.The scale conversions from LCC to canopy chlorophyll content(CCC)and LEWT to canopy equivalent water thickness(CEWT)were calculated.The results showed that LAI,CCC,and CEWT were inversely related with PPC-induced stress.When applying multiple LUTs,the p-values were<0.01;the R2 values for LAI,CCC,and CEWT were 0.71,0.68,and 0.65 with root mean square error(RMSE)(normalized RMSE,NRMSE)values of 0.38(0.16),17.56μg cm-2(0.20),and 0.02 cm(0.51),respectively.Compared to the values obtained for the traditional PROSAIL model,for October,R2 values increased by 0.05 and 0.10 and NRMSE decreased by 0.09 and 0.02 for CCC and CEWT,respectively and RMSE decreased by 0.35μg cm-2 for CCC.The feasibility of the inverse strategy for integrating pest-induced stress factors into the PROSAIL model,while establishing multiple LUTs under different pest-induced damage levels,was successfully demonstrated and can potentially enhance future vegetation parameter inversion and monitoring of bamboo forest health and ecosystems.展开更多
The influence of humic substances (HS) formulations derived from sedimentary and compost sources was studied on plant growth at cell level and chlorophyll retention during accelerated senescence of leaf tissue. The di...The influence of humic substances (HS) formulations derived from sedimentary and compost sources was studied on plant growth at cell level and chlorophyll retention during accelerated senescence of leaf tissue. The direct effect of HS formulations was studied on cell expansion using cucumber and radish cotyledon expansion test. The cucumber hypocotyl elongation test was used to study the effect on cell elongation. Chlorophyll pigment retention in excised leaf tissue incubated in dark with high temperature was assessed to study the effect on leaf senescence. Explant tissues were incubated directly in the solutions of the formulations at the concentration recommended for foliar application to the crop plants. HS formulations showed significant variations in their direct bio-stimulatory effects. Formulations derived from compost sources were found superior in terms of inducing a direct stimulatory effect on cell expansion and cell elongation and in maintaining chlorophyll pigment retention during accelerated senescence. HS from sedimentary sources stimulated cell expansion and delayed chlorophyll degradation to a lesser extent compared to HS from compost. However, HS formulations derived from sedimentary sources used in this study were not effective in inducing cell elongation in the cucumber hypocotyl elongation test. The direct bio-stimulatory effect of HS formulations differed significantly between the formulations that were evaluated.展开更多
Arctic Ocean(AO)climate is closely related to sea ice concentration(ICE)and chlorophyll_a(CHL)concentrations.From 2003–2014,the spatial average concentrations of CHL,ICE,sea surface temperature(SST),wind speed(WIND)i...Arctic Ocean(AO)climate is closely related to sea ice concentration(ICE)and chlorophyll_a(CHL)concentrations.From 2003–2014,the spatial average concentrations of CHL,ICE,sea surface temperature(SST),wind speed(WIND)in the Greenland Sea region(GS)(20˚W–10˚E,70˚–80˚N)and the Barents Sea region(BS)(30˚–50˚E,70˚–80˚N)are analysed and com-pared.Higher CHL was observed in BS,about 60%higher than that in GS.Compared with the northern regions of BS and GS(BSN and GSN),CHL in the southern region of BS and GS(BSS and GSS)increased by 77%and 42%respectively.More ice melting in BSN is the main reason for phytoplankton proliferation.In 2010,there was an unusual peak of CHL concentration in GSN.The sea-sonal peaks of CHL appeared two weeks earlier in BS than in GS.The earlier and more extensive ice melting and the persistent nega-tive North Atlantic Oscillation(NAO)index may be the reasons for higher CHL blooms in 2010.The spatial average ICE concentra-tion of BS in BSN and BSS is 27%and 1.2%respectively.Negative NAO in the previous winter may lead to an increase in ICE in spring.NAO has a great influence on CHL and ICE in GS.Ice melting is positively correlated with CHL,especially in GS in recent decades,CHL has a significant positive correlation with surface mass concentration of dimethylsulfide(DMS),especially in GS.As an indicator of Arctic warming,BS needs more attention from Arctic researchers.展开更多
Luzon Strait is the main channel connecting the South China Sea(SCS)and the western Pacific,with complex atmospheric and oceanic dynamic processes.Based on 44 days of glider measurements and satellite observations,we ...Luzon Strait is the main channel connecting the South China Sea(SCS)and the western Pacific,with complex atmospheric and oceanic dynamic processes.Based on 44 days of glider measurements and satellite observations,we investigated the temporal and vertical variations of chlorophyll-a(Chl-a)concentration in the Luzon Strait from July 25 to September 6,2019.The Chl a was mainly distributed above 200 m and concentrated in the subsurface chlorophyll maximum(SCM)layer.The depth of SCM ranged between 50 m and 110 m,and the magnitude of SCM varied from 0.42 mg/m3 to 1.12 mg/m3.The variation of Chl a was identified with three stages responding to different dynamic processes.Under the influence of Kuroshio intrusion,the SCM depth sharply deepened,and its magnitude decreased in Stage 1.Afterward,a prominent Chl-a bloom was observed in the SCM layer from August 6 to August 16.The Chl-a bloom in Stage 2 was related to the influence of a cyclonic eddy,which uplifted of the thermocline and thus the deep nutrients.During Stage 3,prolonged heavy rainfall in the northeastern SCS resulted in a significant salinity decrease in the upper ocean.The convergence of upper water deepened the thermocline and the mixed layer.Thus,the Chl a decreased in the SCM layer but increased in the surface layer.In particular,a typhoon passed through the Luzon Strait on August 24,which induced the Chl a increase in the upper 50 m.However,there was little change in the depth-integrated Chl a(0-200 m),indicating that the Chl a increase in the surface layer was likely associated with physical entrainment of SCM caused by strong mixing,rather than the phytoplankton bloom in the upper water column.Underwater gliders provide frequent autonomous observations that help us understand the regional ocean’s complex dynamic processes and biological responses.展开更多
Chlorophyll a concentration(CHL)is an important proxy of the marine ecological environment and phytoplankton production.Long-term trends in CHL of the South China Sea(SCS)reflect the changes in the ecosystem’s produc...Chlorophyll a concentration(CHL)is an important proxy of the marine ecological environment and phytoplankton production.Long-term trends in CHL of the South China Sea(SCS)reflect the changes in the ecosystem’s productivity and functionality in the regional carbon cycle.In this study,we applied a previously reconstructed 15-a(2005–2019)CHL product,which has a complete coverage at 4 km and daily resolutions,to analyze the long-term trends of CHL in the SCS.Quantile regression was used to elaborate on the long-term trends of high,median,and low CHL values,as an extended method of conventional linear regression.The results showed downward trends of the SCS CHL for the 75th,50th,and 25th quantile in the past 15 a,which were−0.0040 mg/(m^(3)·a)(−1.62%per year),−0.0023 mg/(m^(3)·a)(−1.10%per year),and−0.0019 mg/(m^(3)·a)(−1.01%per year).The negative trends in winter(November to March)were more prominent than those in summer(May to September).In terms of spatial distribution,the downward trend was more significant in regions with higher CHL.These led to a reduced standard deviation of CHL over time and space.We further explored the influence of various dynamic factors on CHL trends for the entire SCS and two typical systems(winter Luzon Strait(LZ)and summer Vietnam Upwelling System(SV))with single-variate linear regression and multivariate Random Forest analysis.The multivariate analysis suggested the CHL trend pattern can be best explained by the trends of wind speed and mixed-layer depth.The divergent importance of controlling factors for LZ and SV can explain the different CHL trends for the two systems.This study expanded our understanding of the long-term changes of CHL in the SCS and provided a reference for investigating changes in the marine ecosystem.展开更多
[Objectives]To study the photosynthetic response mechanism of persimmon seedlings to salt stress.[Methods]The chlorophyll fluorescence parameters of Diospyros virginiana and Diospyros lotus seedlings under 4%salt stre...[Objectives]To study the photosynthetic response mechanism of persimmon seedlings to salt stress.[Methods]The chlorophyll fluorescence parameters of Diospyros virginiana and Diospyros lotus seedlings under 4%salt stress were studied by pot culture salt control method,including the minimal fluorescence(F_(0)),maximum fluorescence(F_(m)),potential activity of PS II(F_(v)/F_(0)),maximum photochemical efficiency of PS II(F_(v)/F_(m)),electron transport rate(ETR),actual photochemical efficiency of PS II(Y II),and photochemical quenching coefficient(q_(p)).[Results]Under 4%salt stress,the maximum fluorescence(F_(m)),maximum photochemical efficiency of PS II(F v/F m),and photochemical quenching coefficient(q_(p))of two persimmon plants decreased with time.The potential activity of PS II(F_(v)/F_(0)),actual photochemical efficiency of PS II(Y_(II)),and electron transport rate(ETR)decreased under salt stress.[Conclusions]This study indicates that the PS II reaction center in the persimmon leaves was damaged and the electron transport at the acceptor side was damaged under salt stress.It is expected to lay a foundation for the analysis of salt-tolerance mechanism of persimmon plants.展开更多
As global temperature rise,the threat of heat stress to rapeseed production is becoming more obvious.Exploring the response characteristics of two important biological pathways,oil accumulation and photosynthesis,to h...As global temperature rise,the threat of heat stress to rapeseed production is becoming more obvious.Exploring the response characteristics of two important biological pathways,oil accumulation and photosynthesis,to heat stress during B.napus seed filling is helpful in the genetic improvement of heat-tolerant rapeseed.The effects of heat stress on seed oil accumulation and chlorophyll fluorescence characteristics of 29 B.napus germplasms with different oil content and environmental sensitivity,including 6 rapeseed varieties which exhibited environmentsensitive/insensitive and with high,medium or low oil content,were tested by whole plant heat stress or the in vitro silique culture system.Both assay exhibited similar trend on oil content of the rapeseed germplasms.The heat effect on the chlorophyll fluorescence kinetic parameters F_(v)/F_(m),ETR and Y(Ⅱ)were also consistent.Heat stress significantly decreased oil content,although there was abundant genetic variation on heat tolerance among the genotypes.Correlation analysis showed that the decrease rate of F_(v)/F_(m) of silique heat-stressed B.napus developing seed was positive correlative to the decrease rate of mature seed oil content of the whole plant heat-stressed rapeseed(R=0.9214,P-value<0.01).Overall,the results indicated that heat stress inhibited oil accumulation and photosynthesis in B.napus developing seed.The decrease rate of chlorophyll fluorescence parameter F_(v)/F_(m) of heat-stressed developing seed could be used as the index of heat tolerant rapeseed identification.Further,two heat insensitive rapeseed varieties with high oil content were identified.展开更多
Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment.This study investigated the variability in the concentrations of carotenoids a...Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment.This study investigated the variability in the concentrations of carotenoids and chlorophylls and revealed their associations with other nutritional quality traits in a genetically diverse set of Chinese soybean accessions comprised of cultivars and landraces.Genotype,planting year,accession type,seed cotyledon color,and ecoregion of origin significantly influenced the accumulation of carotenoids and chlorophylls.The mean total carotenoid content was in the range of 8.15–14.72μg g–1 across the ecoregions.The total carotenoid content was 1.2-fold higher in the landraces than in the cultivars.Soybeans with green cotyledons had higher contents of carotenoids and chlorophylls than those with yellow cotyledons.Remarkably,lutein was the most abundant carotenoid in all the germplasms,ranging from 1.35–37.44μg g–1.Carotenoids and chlorophylls showed significant correlations with other quality traits,which will help to set breeding strategies for enhancing soybean carotenoids without affecting the other components.Collectively,our results demonstrate that carotenoids are adequately accumulated in soybean seeds,however,they are strongly influenced by genetic factors,accession type,and germplasm origin.We identified novel germplasms with the highest total carotenoid contents across the various ecoregions of China that could serve as the genetic materials for soybean carotenoid breeding programs,and thereby as the raw materials for food sectors,pharmaceuticals,and the cosmetic industry.展开更多
Ocimum gratissimum is an essential plant because of its wide food and medicinal usage.Despite its relevance,its morpho-physiological compositions are influenced by several abiotic stresses.Hence,this study exami...Ocimum gratissimum is an essential plant because of its wide food and medicinal usage.Despite its relevance,its morpho-physiological compositions are influenced by several abiotic stresses.Hence,this study examined the effects of water stress on the growth and chlorophyll contents of O.gratissimum.Seedlings of O.gratissimum were grown in twenty-four pots,two per pot and were arranged using a complete randomized design with four groups:Very Wet O.gratissimum(VWO),Moderately Water Stress O.gratissimum(MWSO),Strongly Water Stress O.gratissimum(SWSO)and Adequately Watered O.gratissimum(AWO)as control.Fifty centiliters of water was applied in AWO once daily,VWO twice daily,MSWO once in three days and SWSO once a week.Growth parameters:Stem height,number of leaves,leaf area,stem girth and petiole length were determined one week after treatment for six weeks.Chlorophyll contents were determined at two weeks intervals after treatment for eight weeks.Descriptive statistics such as mean±standard deviation and one-way Analysis of Variance(p<0.05)were done using SAS software.Results obtained showed the highest mean stem height(27.50±0.29 cm),number of leaves(37.00±9.0),leaf area(735.7±4.12 cm^(2)),stem girth(0.40±0.00 cm)and petiole length(7.20±0.40 cm)in VWO.Similar results were obtained for chlorophyll(56.70±0.65 mg^(-1)).It could be concluded that regular watering of O.gratissimum could promote growth and increase chlorophyll contents of the plant.展开更多
Cotton has enormous economic potential,providing high-quality protein,oil,and fibre.But the comprehensive utilization of cottonseed is limited by the presence of pigment gland and its inclusion.Pigment gland is a comm...Cotton has enormous economic potential,providing high-quality protein,oil,and fibre.But the comprehensive utilization of cottonseed is limited by the presence of pigment gland and its inclusion.Pigment gland is a common characteristic of Gossypium genus and its relatives,appearing as visible dark opaque dots in most tissues and organs of cotton plants.Secondary metabolites,such as gossypol,synthesized and stored in the cavities of pigment glands act as natural phytoalexins,but are toxic to humans and other monogastric animals.However,only a few cotton genes have been identified as being associated with pigment gland morphogenesis to date,and the developmental processes and regulatory mechanism involved in pigment gland formation remain largely unclear.Here,the research progress on the process of pigment gland morphogenesis and the genetic basis of cotton pigment glands is reviewed,for providing a theoretical basis for cultivating cotton with the ideal pigment gland trait.展开更多
基金Supported by the Fundamental Research Funds for the Central Universities(Nos.202341017,202313024)。
文摘Chlorophyll-a(Chl-a)concentration is a primary indicator for marine environmental monitoring.The spatio-temporal variations of sea surface Chl-a concentration in the Yellow Sea(YS)and the East China Sea(ECS)in 2001-2020 were investigated by reconstructing the MODIS Level 3 products with the data interpolation empirical orthogonal function(DINEOF)method.The reconstructed results by interpolating the combined MODIS daily+8-day datasets were found better than those merely by interpolating daily or 8-day data.Chl-a concentration in the YS and the ECS reached its maximum in spring,with blooms occurring,decreased in summer and autumn,and increased in late autumn and early winter.By performing empirical orthogonal function(EOF)decomposition of the reconstructed data fields and correlation analysis with several potential environmental factors,we found that the sea surface temperature(SST)plays a significant role in the seasonal variation of Chl a,especially during spring and summer.The increase of SST in spring and the upper-layer nutrients mixed up during the last winter might favor the occurrence of spring blooms.The high sea surface temperature(SST)throughout the summer would strengthen the vertical stratification and prevent nutrients supply from deep water,resulting in low surface Chl-a concentrations.The sea surface Chl-a concentration in the YS was found decreased significantly from 2012 to 2020,which was possibly related to the Pacific Decadal Oscillation(PDO).
基金funded by Livelihood Plan Project of Department of Science and Technology of Liaoning Province(2021JH2/10300069,2019-ZD-0845)Department of Education of Liaoning Province(LJKZ0918)National College Students’Innovation and Entrepreneurship Training Program(202210163013).
文摘Tea pigments have significant effects on human health.However,more attention have been paid to their physiological functions.The aim of this study was to analyze the quantitative and qualitative impact of tea pigments on human health,together with their current and potential future research directions.The study searched and screened 520 publications on WOS from January 2002 to December 2022.The article collected and collated literature published in the last 20 years and analyzed it bibliometrically for years,journals,countries,authors,topics,keywords and strongest citation bursts.The findings of keywords and strongest citation bursts revealed that the most discussed research topics were anticancer,black tea polyphenol,antioxidant,activator inhibitor,in vivo,gut microbiota,and summarize the relevant literature.As a reference for future research,the literature pointed out current shortcomings and speculated future development trend of tea pigments.
基金supported by Iran Research Institute of Forests and Rangelandsthe Laboratory of Horticultural Sciences of the University of Tehran
文摘Heavy metal contamination is one of the most important abiotic stresses affecting physiological activities of plants.We investigated the effects of cadmium(Cd) and lead(Pb) on chlorophyll fluorescence(Fv/Fm,Fo,and Fm),photosynthetic pigments(chlorophyll a and b),and proline in one-year-old seedlings of Robinia pseudoacacia.The seedlings were treated twice over a period of 10 days with Cd and Pb at concentrations of 0,250,500,1000 and2000 mg L-1.Saline solution containing Cd and Pb was sprayed on the leaves.Chlorophyll and proline contents were measured after 10 days.Chlorophyll fluorescence of R.pseudoacacia was affected slightly by high concentrations(1000,2000 mg L-1) of Cd and Pb.Chlorophyll a and a/b increased at 1000 and 2000 mg L-1of Cd and proline content of leaves was similar in all treatments of Cd and Pb.Our results indicated that photosynthetic sensitivity of R.pseudoacacia to Cd and Pb contamination was weak.Photosystem II chlorophyll pigments were not damaged by Pb and Cd stress.We conclude that chlorophyll fluorescence along with chlorophyll and proline contents are useful indicators of Cd and Pb stresses in R.pseudoacacia which widely planted in urban polluted regions in Iran.
文摘For plants growing in parks and along the roadsides of a city, the environmental and seasonal regulation of growth, or photosynthesis, is seldom assessed. The phenology of plants may differ due to varying environments, which may result in different growth or adaptability to local environments. Therefore, we explored several assays and optical indicators of photosynthesis and stress in three tree species (Prunus yedoensis Matsum, Zelkova serrata Makino and Acer palmatum Thunb. ) and two herbaceous species (Artemisia princeps Pamp and Taraxacum officinale Weber)growing commonly in three local parks of Changwon city, a large industrial city in Korea. The photochemical reflectance index (PRI), chlorophyll fluorescence, and pigments including chlorophyll and the flavonoids of leaves were monitored over a growing season for two years to evaluate the adaptability of plants to local environments. The values of all measurements exhibited striking seasonal and regional changes. PRI values were closely timed with photosynthetic activity and the pigment formation of leaves, particularly in some tree species. For the tree species, the plants which had the low values of PRI during the active growing season showed low levels of both chlorophyll fluorescence and high level of flavonoid, indicating that these plants were experiencing low photosynthetic activity and the specific needs in growth and development were not sufficiently provided by the local environment. Our results indicate that PRI provided a clear optical indicator of plant adaptability to the local environment and may provide a useful metric of effective growth using remote sensing measurements. Furthermore, the periodic PRI measurement is encouraged to be included in the surveillance program for city plant management.
基金supported by grants from FONCyT,CONICET and the National University of Cuyo.
文摘Pigments present in the brown-greenish C morph of an intracellular endosymbiont of Pomacea canaliculata were investigated.Acetone extracts of the endosymbiotic corpuscles showed an absorption spectrum similar to that of chlorophylls.Three fractions obtained from silica gel column chromatography of the acetone extracts(CI,CII and CIII),were studied by positive ion fast atom bombardment-mass spectrometry(FAB–MS)and hydrogen-nuclear magnetic resonance(H-NMR).Results indicated the presence of(1)a sterol in the yellow colored CI fraction;(2)a mixture of pheophorbides a and b in the major green fraction,CII;and(3)a modified pheophorbide a in the smaller green fraction,CIII.Aqueous extracts of the C endosymbiont did not show evidence of the occurrence of C-phycocyanin,allophycocyanin or phycoerithrin(light absorption,fluorescence emission,and electrophoresis of the protein moieties)while cyanobacterial cells(Nostoc sp.)showed evidence of C-phycocyanin and allophycocyanin.The possible phylogenetic and functional significance of the pigments present in the C endosymbiont is discussed.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.32072623,31700611)。
文摘Flavonoids are critical secondary metabolites that determine the health benefits and flavor of tea,while chlorophylls are important contributors to the appearance of tea.However,transcription factors(TFs)that can integrate both chlorophyll biosynthesis and flavonoid accumulation in response to specific light signals are rarely identified.In this study,we report that the GOLDEN 2-LIKE TF pair,CsGLK1 and CsGLK2,orchestrate UV-B-induced responses in the chlorophyll biosynthesis and flavonoid accumulation of tea leaves.The absence of solar UV-B reduced the transcriptional expression of CsGLKs in the tea leaves and was highly correlated with a decrease in flavonoid levels(especially flavonol glycosides)and the expression of genes and TFs involved in chlorophyll biosynthesis and flavonoid accumulation.In vivo and in vitro molecular analyses showed that CsGLKs could be regulated by the UV-B signal mediator CsHY5,and could directly bind to the promoters of gene and TF involved in light-harvesting(CsLhcb),chlorophyll biosynthesis(CsCHLH,CsHEMA1,and CsPORA),and flavonoid accumulation(CsMYB12,CsFLSa,CsDFRa,and CsLARa),eventually leading to UV-B-induced responses in the chlorophylls and flavonoids of tea leaves.Furthermore,UV-B exposure increased the levels of total flavonoids,CsGLK1 protein,and expression of CsGLKs and target genes in the tea leaves.These results indicate that CsGLKs may modulate tea leaf characteristics by regulating chlorophyll biosynthesis and flavonoid accumulation in response to solar UV-B.As the first report on UV-B-induced changes in flavonoid and chlorophyll regulation mediated by CsGLKs,this study improves our understanding of the environmental regulations regarding tea quality and sheds new light on UV-B-induced flavonoid responses in higher plants.
基金supported by the National Natural Science Foundation of China (32241042 and 31771807)the National Key R&D Program of China (2021YFF1000103)+1 种基金the China Agricultural Research System (CARS-06-04)the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences。
文摘Chlorophyll (Chl) content,especially Chl b content,and stomatal conductance (G_s) are the key factors affecting the net photosynthetic rate (P_n).Setaria italica,a diploid C_4 panicoid species with a simple genome and high transformation efficiency,has been widely accepted as a model in photosynthesis and drought-tolerance research.The current study characterized Chl content,G_s,and P_n of 48 Setaria mutants induced by ethyl methanesulfonate.A total of 24,34,and 35 mutants had significant variations in Chl content,G_s,and P_n,respectively.Correlation analysis showed a positive correlation between increased G_s and increased P_n,and a weak correlation between decreased Chl b content and decreased P_n was also found.Remarkably,two mutants behaved with significantly decreased Chl b content but increased P_n compared to Yugu 1.Seven mutants behaved with significantly decreased G_s but did not decrease P_(n )compared to Yugu 1.The current study thus identified various genetic lines,further exploration of which would be beneficial to elucidate the relationship between Chl content,G_s,and P_n and the mechanism underlying why C_4 species are efficient at photosynthesis and water saving.
基金supported by the Ministry of Education,Science and Technological Development of the Republic of Serbia,Grant No.451–03–68/2022–124/200032.
文摘Salinity is one of the major abiotic factors that limit the growth and productivity of plants.Foliar application of plant growth regulators(PGRs)may help plants ameliorate the negative impacts of salinity.Thus,a field experiment was conducted at the Botanical Garden University of Balochistan,Quetta,to explore the potential role of PGRs,i.e.,moringa leaf extract(MLE;10%),proline(PRO;1μM),salicylic acid(SA;250μM),and thiourea(TU;10 mM)in ameliorating the impacts of salinity(120 mM)on Plantago ovata,an important medicinal plant.Salinity hampered plant photosynthetic pigments and metabolites but elevated oxidative parameters.However,foliar application of PGRs enhanced photosynthetic pigments,including Chl b(21.11%),carotenoids(57.87%)except Chl a,activated the defense mechanisms by restoring and enhancing the metabolites,i.e.,soluble sugars(49.68%),soluble phenolics(33.34%),and proline(31.47%),significantly under salinity stress.Furthermore,foliar supplementation of PGRs under salt stress led to a decrease of about 43.02%and 43.27%in hydrogen peroxide and malondialdehyde content,respectively.Thus,PGRs can be recommended for improved photosynthetic efficiency and metabolite content that can help to get better yield under salt stress,with the best and most effective treatments being those of PRO and MLE to predominately ameliorate the harsh impacts of salinity.
基金supported by National Natural Science Foundation of China (Grant No.31700609)Natural Science Foundation of Shandong Province (Grant No.ZR2017BC086)State Key Laboratory of Tea Plant Biology and Utilization Open Foundation(Grant No.SKLTOF20180104)。
文摘Chlorophyll contributes to tea coloration, which is an important factor in tea quality. Chlorophyll metabolism is induced by light, but the transcriptional regulation responsible for light-induced chlorophyll metabolism is largely unknown in tea leaves. Here, we characterized a chlorophyllase1 gene CsCLH1 from young tea leaves and showed it is essential for chlorophyll metabolism, using transient overexpression and silencing in tea leaves and ectopic overexpression in Arabidopsis. CsCLH1 was significantly induced by high light. The DOF protein CsDOF3, an upstream direct regulator of CsCLH1, was also identified. Acting as a nuclear-localized transcriptional factor, CsDOF3 responded for light and repressed CsCLH1 transcription and increased chlorophyll content by directly binding to the AAAG cis-element in the CsCLH1 promoter. CsDOF3was able to physically interact with the R2R3-MYB transcription factor CsMYB308 and interfere with transcriptional activity of CsCLH1. In addition, CsMYB308 binds to the CsCLH1 promoter to enhance CsCLH1 expression and decrease chlorophyll content. CsMYB308 and CsDOF3 act as an antagonistic complex to regulate CsCLH1 transcription and chlorophyll in young leaves. Collectively, the study adds to the understanding of the transcriptional regulation of chlorophyll in tea leaves in response to light and provides a basis for improving the appearance of tea.
基金The Global Change and Air-Sea Interaction Program under contract Nos GASI-02-IND-ST-Sspr and GASI-03-01-03-03the National Natural Science Foundation of China under contract No.41506185the Special Funds for Basic Ocean Science Research of the First Institute of Oceanography,State Oceanic Administration of China under contract Nos 2013T04 and 2012T08
文摘Upwelling occurs on the coast of Java between June and October, forced by local alongshore winds associated with the southeasterly monsoon. This causes variations in phytoplankton community composition in the upwelling zone compared with the surrounding offshore area. Based on pigments analysis with subsequent calculations of group contributions to total chlorophyll a(Chl a) using CHEMTAX, we studied the distribution and composition of phytoplankton assemblages in the subsurface chlorophyll maximum along the south coast of Java and the influence of upwelling. Nineteen phytoplankton pigments were identified using high-performance liquid chromatography, and CHEMTAX analysis associated these to ten major phytoplankton groups. The phytoplankton community in the coastal area influenced by upwelling was characterized by high Chl a and fucoxanthin concentrations, indicating the dominance of diatoms. In contrast, in the offshore area, the Chl a and fucoxanthin concentrations declined to very low levels and the community was dominated by haptophytes represented by 19′-Hexanoyloxyfucoxanthin. Accordingly, microphytoplankton was found to be the major size class in the coastal area influenced by upwelling, while nanophytoplankton was most abundant in the offshore area. Low concentrations of other accessory pigments indicated less contribution from dinoflagellates,prasinophytes, chlorophytes and cryptophytes. Photo-pigment indices revealed that photosynthetic carotenoids(PSCs) were the largest component of the pigment pool, exceeding the proportion of Chl a, with the average PSCTP up to 0.62. These distribution trends can mainly be explained by phytoplankton adaption strategies to upwelling and subsurface conditions by changing species composition and adjusting the pigment pool.
基金funded by the National Natural Science Foundation of China(42071300)the Fujian Province Natural Science(2020J01504)+4 种基金the China Postdoctoral Science Foundation(2018M630728)the Open Fund of Fujian Provincial Key Laboratory of Resources and Environment Monitoring&Sustainable Management and Utilization(ZD202102)the Program for Innovative Research Team in Science and Technology in Fujian Province University(KC190002)the Open Fund of University Key Lab of Geomatics Technology and Optimize Resources Utilization in Fujian Province(fafugeo201901)supported by the Research Project of Jinjiang Fuda Science and Education Park Development Center(2019-JJFDKY-17)。
文摘Biochemical components of Moso bamboo(Phyllostachys pubescens)are critical to physiological and ecological processes and play an important role in the material and energy cycles of the ecosystem.The coupled PROSPECT with SAIL(PROSAIL)radiative transfer model is widely used for vegetation biochemical component content inversion.However,the presence of leaf-eating pests,such as Pantana phyllostachysae Chao(PPC),weakens the performance of the model for estimating biochemical components of Moso bamboo and thus must be considered.Therefore,this study considered pest-induced stress signals associated with Sentinel-2A/B images and field data and established multiple sets of biochemical canopy reflectance look-up tables(LUTs)based on the PROSAIL framework by setting different parameter ranges according to infestation levels.Quantitative inversions of leaf area index(LAI),leaf chlorophyll content(LCC),and leaf equivalent water thickness(LEWT)were derived.The scale conversions from LCC to canopy chlorophyll content(CCC)and LEWT to canopy equivalent water thickness(CEWT)were calculated.The results showed that LAI,CCC,and CEWT were inversely related with PPC-induced stress.When applying multiple LUTs,the p-values were<0.01;the R2 values for LAI,CCC,and CEWT were 0.71,0.68,and 0.65 with root mean square error(RMSE)(normalized RMSE,NRMSE)values of 0.38(0.16),17.56μg cm-2(0.20),and 0.02 cm(0.51),respectively.Compared to the values obtained for the traditional PROSAIL model,for October,R2 values increased by 0.05 and 0.10 and NRMSE decreased by 0.09 and 0.02 for CCC and CEWT,respectively and RMSE decreased by 0.35μg cm-2 for CCC.The feasibility of the inverse strategy for integrating pest-induced stress factors into the PROSAIL model,while establishing multiple LUTs under different pest-induced damage levels,was successfully demonstrated and can potentially enhance future vegetation parameter inversion and monitoring of bamboo forest health and ecosystems.
文摘The influence of humic substances (HS) formulations derived from sedimentary and compost sources was studied on plant growth at cell level and chlorophyll retention during accelerated senescence of leaf tissue. The direct effect of HS formulations was studied on cell expansion using cucumber and radish cotyledon expansion test. The cucumber hypocotyl elongation test was used to study the effect on cell elongation. Chlorophyll pigment retention in excised leaf tissue incubated in dark with high temperature was assessed to study the effect on leaf senescence. Explant tissues were incubated directly in the solutions of the formulations at the concentration recommended for foliar application to the crop plants. HS formulations showed significant variations in their direct bio-stimulatory effects. Formulations derived from compost sources were found superior in terms of inducing a direct stimulatory effect on cell expansion and cell elongation and in maintaining chlorophyll pigment retention during accelerated senescence. HS from sedimentary sources stimulated cell expansion and delayed chlorophyll degradation to a lesser extent compared to HS from compost. However, HS formulations derived from sedimentary sources used in this study were not effective in inducing cell elongation in the cucumber hypocotyl elongation test. The direct bio-stimulatory effect of HS formulations differed significantly between the formulations that were evaluated.
基金the National Natural Science Foundation of China(No.41276097)for providing research funding for this project.
文摘Arctic Ocean(AO)climate is closely related to sea ice concentration(ICE)and chlorophyll_a(CHL)concentrations.From 2003–2014,the spatial average concentrations of CHL,ICE,sea surface temperature(SST),wind speed(WIND)in the Greenland Sea region(GS)(20˚W–10˚E,70˚–80˚N)and the Barents Sea region(BS)(30˚–50˚E,70˚–80˚N)are analysed and com-pared.Higher CHL was observed in BS,about 60%higher than that in GS.Compared with the northern regions of BS and GS(BSN and GSN),CHL in the southern region of BS and GS(BSS and GSS)increased by 77%and 42%respectively.More ice melting in BSN is the main reason for phytoplankton proliferation.In 2010,there was an unusual peak of CHL concentration in GSN.The sea-sonal peaks of CHL appeared two weeks earlier in BS than in GS.The earlier and more extensive ice melting and the persistent nega-tive North Atlantic Oscillation(NAO)index may be the reasons for higher CHL blooms in 2010.The spatial average ICE concentra-tion of BS in BSN and BSS is 27%and 1.2%respectively.Negative NAO in the previous winter may lead to an increase in ICE in spring.NAO has a great influence on CHL and ICE in GS.Ice melting is positively correlated with CHL,especially in GS in recent decades,CHL has a significant positive correlation with surface mass concentration of dimethylsulfide(DMS),especially in GS.As an indicator of Arctic warming,BS needs more attention from Arctic researchers.
基金Supported by the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.2019BT02H594)the Chinese Academy of Sciences(Nos.XDB42010305,XDA15020901,133244KYSB20190031,SCSIO202201,SCSIO202204)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA13010500)the National Natural Science Foundation of China(No.41976024)the Independent Research Project Program of State Key Laboratory of Tropical Oceanography(No.LTOZZ2101)。
文摘Luzon Strait is the main channel connecting the South China Sea(SCS)and the western Pacific,with complex atmospheric and oceanic dynamic processes.Based on 44 days of glider measurements and satellite observations,we investigated the temporal and vertical variations of chlorophyll-a(Chl-a)concentration in the Luzon Strait from July 25 to September 6,2019.The Chl a was mainly distributed above 200 m and concentrated in the subsurface chlorophyll maximum(SCM)layer.The depth of SCM ranged between 50 m and 110 m,and the magnitude of SCM varied from 0.42 mg/m3 to 1.12 mg/m3.The variation of Chl a was identified with three stages responding to different dynamic processes.Under the influence of Kuroshio intrusion,the SCM depth sharply deepened,and its magnitude decreased in Stage 1.Afterward,a prominent Chl-a bloom was observed in the SCM layer from August 6 to August 16.The Chl-a bloom in Stage 2 was related to the influence of a cyclonic eddy,which uplifted of the thermocline and thus the deep nutrients.During Stage 3,prolonged heavy rainfall in the northeastern SCS resulted in a significant salinity decrease in the upper ocean.The convergence of upper water deepened the thermocline and the mixed layer.Thus,the Chl a decreased in the SCM layer but increased in the surface layer.In particular,a typhoon passed through the Luzon Strait on August 24,which induced the Chl a increase in the upper 50 m.However,there was little change in the depth-integrated Chl a(0-200 m),indicating that the Chl a increase in the surface layer was likely associated with physical entrainment of SCM caused by strong mixing,rather than the phytoplankton bloom in the upper water column.Underwater gliders provide frequent autonomous observations that help us understand the regional ocean’s complex dynamic processes and biological responses.
基金The National Natural Science Foundation of China under contract No.41906019.
文摘Chlorophyll a concentration(CHL)is an important proxy of the marine ecological environment and phytoplankton production.Long-term trends in CHL of the South China Sea(SCS)reflect the changes in the ecosystem’s productivity and functionality in the regional carbon cycle.In this study,we applied a previously reconstructed 15-a(2005–2019)CHL product,which has a complete coverage at 4 km and daily resolutions,to analyze the long-term trends of CHL in the SCS.Quantile regression was used to elaborate on the long-term trends of high,median,and low CHL values,as an extended method of conventional linear regression.The results showed downward trends of the SCS CHL for the 75th,50th,and 25th quantile in the past 15 a,which were−0.0040 mg/(m^(3)·a)(−1.62%per year),−0.0023 mg/(m^(3)·a)(−1.10%per year),and−0.0019 mg/(m^(3)·a)(−1.01%per year).The negative trends in winter(November to March)were more prominent than those in summer(May to September).In terms of spatial distribution,the downward trend was more significant in regions with higher CHL.These led to a reduced standard deviation of CHL over time and space.We further explored the influence of various dynamic factors on CHL trends for the entire SCS and two typical systems(winter Luzon Strait(LZ)and summer Vietnam Upwelling System(SV))with single-variate linear regression and multivariate Random Forest analysis.The multivariate analysis suggested the CHL trend pattern can be best explained by the trends of wind speed and mixed-layer depth.The divergent importance of controlling factors for LZ and SV can explain the different CHL trends for the two systems.This study expanded our understanding of the long-term changes of CHL in the SCS and provided a reference for investigating changes in the marine ecosystem.
基金Supported by Science and Technology Research Project of Henan Provincial Science and Technology Department(222102110444)Introduction of Talent of Pingdingshan University(PXY-BSQD-202109).
文摘[Objectives]To study the photosynthetic response mechanism of persimmon seedlings to salt stress.[Methods]The chlorophyll fluorescence parameters of Diospyros virginiana and Diospyros lotus seedlings under 4%salt stress were studied by pot culture salt control method,including the minimal fluorescence(F_(0)),maximum fluorescence(F_(m)),potential activity of PS II(F_(v)/F_(0)),maximum photochemical efficiency of PS II(F_(v)/F_(m)),electron transport rate(ETR),actual photochemical efficiency of PS II(Y II),and photochemical quenching coefficient(q_(p)).[Results]Under 4%salt stress,the maximum fluorescence(F_(m)),maximum photochemical efficiency of PS II(F v/F m),and photochemical quenching coefficient(q_(p))of two persimmon plants decreased with time.The potential activity of PS II(F_(v)/F_(0)),actual photochemical efficiency of PS II(Y_(II)),and electron transport rate(ETR)decreased under salt stress.[Conclusions]This study indicates that the PS II reaction center in the persimmon leaves was damaged and the electron transport at the acceptor side was damaged under salt stress.It is expected to lay a foundation for the analysis of salt-tolerance mechanism of persimmon plants.
基金funded by the Natural Science Foundation of Zhejiang Province(LY20C130006)the National Natural Science Foundation of China(32172018)the State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products(2010DS700124-ZZ1805).
文摘As global temperature rise,the threat of heat stress to rapeseed production is becoming more obvious.Exploring the response characteristics of two important biological pathways,oil accumulation and photosynthesis,to heat stress during B.napus seed filling is helpful in the genetic improvement of heat-tolerant rapeseed.The effects of heat stress on seed oil accumulation and chlorophyll fluorescence characteristics of 29 B.napus germplasms with different oil content and environmental sensitivity,including 6 rapeseed varieties which exhibited environmentsensitive/insensitive and with high,medium or low oil content,were tested by whole plant heat stress or the in vitro silique culture system.Both assay exhibited similar trend on oil content of the rapeseed germplasms.The heat effect on the chlorophyll fluorescence kinetic parameters F_(v)/F_(m),ETR and Y(Ⅱ)were also consistent.Heat stress significantly decreased oil content,although there was abundant genetic variation on heat tolerance among the genotypes.Correlation analysis showed that the decrease rate of F_(v)/F_(m) of silique heat-stressed B.napus developing seed was positive correlative to the decrease rate of mature seed oil content of the whole plant heat-stressed rapeseed(R=0.9214,P-value<0.01).Overall,the results indicated that heat stress inhibited oil accumulation and photosynthesis in B.napus developing seed.The decrease rate of chlorophyll fluorescence parameter F_(v)/F_(m) of heat-stressed developing seed could be used as the index of heat tolerant rapeseed identification.Further,two heat insensitive rapeseed varieties with high oil content were identified.
基金financially supported by the National Natural Science Foundation of China(32161143033 and 32001574)the Agricultural Science and Technology Innovation Program of CAAS(2060203-2).
文摘Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment.This study investigated the variability in the concentrations of carotenoids and chlorophylls and revealed their associations with other nutritional quality traits in a genetically diverse set of Chinese soybean accessions comprised of cultivars and landraces.Genotype,planting year,accession type,seed cotyledon color,and ecoregion of origin significantly influenced the accumulation of carotenoids and chlorophylls.The mean total carotenoid content was in the range of 8.15–14.72μg g–1 across the ecoregions.The total carotenoid content was 1.2-fold higher in the landraces than in the cultivars.Soybeans with green cotyledons had higher contents of carotenoids and chlorophylls than those with yellow cotyledons.Remarkably,lutein was the most abundant carotenoid in all the germplasms,ranging from 1.35–37.44μg g–1.Carotenoids and chlorophylls showed significant correlations with other quality traits,which will help to set breeding strategies for enhancing soybean carotenoids without affecting the other components.Collectively,our results demonstrate that carotenoids are adequately accumulated in soybean seeds,however,they are strongly influenced by genetic factors,accession type,and germplasm origin.We identified novel germplasms with the highest total carotenoid contents across the various ecoregions of China that could serve as the genetic materials for soybean carotenoid breeding programs,and thereby as the raw materials for food sectors,pharmaceuticals,and the cosmetic industry.
文摘Ocimum gratissimum is an essential plant because of its wide food and medicinal usage.Despite its relevance,its morpho-physiological compositions are influenced by several abiotic stresses.Hence,this study examined the effects of water stress on the growth and chlorophyll contents of O.gratissimum.Seedlings of O.gratissimum were grown in twenty-four pots,two per pot and were arranged using a complete randomized design with four groups:Very Wet O.gratissimum(VWO),Moderately Water Stress O.gratissimum(MWSO),Strongly Water Stress O.gratissimum(SWSO)and Adequately Watered O.gratissimum(AWO)as control.Fifty centiliters of water was applied in AWO once daily,VWO twice daily,MSWO once in three days and SWSO once a week.Growth parameters:Stem height,number of leaves,leaf area,stem girth and petiole length were determined one week after treatment for six weeks.Chlorophyll contents were determined at two weeks intervals after treatment for eight weeks.Descriptive statistics such as mean±standard deviation and one-way Analysis of Variance(p<0.05)were done using SAS software.Results obtained showed the highest mean stem height(27.50±0.29 cm),number of leaves(37.00±9.0),leaf area(735.7±4.12 cm^(2)),stem girth(0.40±0.00 cm)and petiole length(7.20±0.40 cm)in VWO.Similar results were obtained for chlorophyll(56.70±0.65 mg^(-1)).It could be concluded that regular watering of O.gratissimum could promote growth and increase chlorophyll contents of the plant.
基金National Key Technology R&D Program of China(2022YFF1001403)National Science Foundation of China(32101764).
文摘Cotton has enormous economic potential,providing high-quality protein,oil,and fibre.But the comprehensive utilization of cottonseed is limited by the presence of pigment gland and its inclusion.Pigment gland is a common characteristic of Gossypium genus and its relatives,appearing as visible dark opaque dots in most tissues and organs of cotton plants.Secondary metabolites,such as gossypol,synthesized and stored in the cavities of pigment glands act as natural phytoalexins,but are toxic to humans and other monogastric animals.However,only a few cotton genes have been identified as being associated with pigment gland morphogenesis to date,and the developmental processes and regulatory mechanism involved in pigment gland formation remain largely unclear.Here,the research progress on the process of pigment gland morphogenesis and the genetic basis of cotton pigment glands is reviewed,for providing a theoretical basis for cultivating cotton with the ideal pigment gland trait.