Simultaneous stresses of salinity and drought often coincide during rice-growing seasons in saline lands,primarily due to insufficient water resources and inadequate irrigation facilities.Consequently,combined salinit...Simultaneous stresses of salinity and drought often coincide during rice-growing seasons in saline lands,primarily due to insufficient water resources and inadequate irrigation facilities.Consequently,combined salinity-drought stress poses a major threat to rice production.In this study,two salinity levels(NS,non-salinity;HS,high salinity)along with three drought treatments(CC,control condition;DJ,drought stress imposed at jointing;DH,drought stress imposed at heading)were performed to investigate their combined influences on leaf photosynthetic characteristics,biomass accumulation,and rice yield formation.Salinity,drought,and their combination led to a shortened growth period from heading to maturity,resulting in a reduced overall growth duration.Grain yield was reduced under both salinity and drought stress,with a more substantial reduction under the combined salinity-drought stress.The combined stress imposed at heading caused greater yield losses in rice compared with the stress imposed at jointing.Additionally,the combined salinity-drought stress induced greater decreases in shoot biomass accumulation from heading to maturity,as well as in shoot biomass and nonstructural carbohydrate(NSC)content in the stem at heading and maturity.However,it increased the harvest index and NSC remobilization reserve.Salinity and drought reduced the leaf area index and SPAD value of flag leaves and weakened the leaf photosynthetic characteristics as indicated by lower photosynthetic rates,transpiration rates,and stomatal conductance.These reductions were more pronounced under the combined stress.Salinity,drought,and especially their combination,decreased the activities of ascorbate peroxidase,catalase,and superoxide dismutase,while increasing the contents of malondialdehyde,hydrogen peroxide,and superoxide radical.Our results indicated a more significant yield loss in rice when subjected to combined salinity-drought stress.The individual and combined stresses of salinity and drought diminished antioxidant enzyme activities,inhibited leaf photosynthetic functions,accelerated leaf senescence,and subsequently lowered assimilate accumulation and grain yield.展开更多
The key to high-yielding peanut cultivation is the optimization of agricultural production practices.Regulating single-seed precise sowing(SSPS)density and paclobutrazol(Pbz)application concentration are effective pra...The key to high-yielding peanut cultivation is the optimization of agricultural production practices.Regulating single-seed precise sowing(SSPS)density and paclobutrazol(Pbz)application concentration are effective practices that increase peanut yield by improving plant architecture,lodging resistance,and photosynthetic characteristics.Therefore,we conducted a two-factor field optimization experiment for the sowing density(D1:1.95×10^(5)plants ha^(-1),D52:2.40×10plants ha^(-1),D3:2.85×10^(5)plants ha^(-1),and D4:3.30×10^(5)plants ha^(-1))and Pbzapplication concentration(P0:0 mg L^(-1)and P1:100 mg L^(-1)).The objective was to optimize agricultural production practices and provide a theoretical basis for highyielding peanut cultivation by evaluating the effects of sowing density and Pbzapplication on plant architecture,lodging resistance,photosynthetic characteristics,and yield.The results showed that at the same Pbzapplication concentration,increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity.At the same sowing density,Pbzapplication reduced lodging percentage by decreasing plant height(PH),improving lignin biosynthesis-related enzyme activities,and enhancing stem puncture strength(SPS)and breaking strength(SBS).The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata,resulting in the increase in relative chlorophyll content and net photosynthetic rate(Pn)of leaves.Furthermore,D3P1treatment had the highest peanut yield among all treatments.In summary,the production strategy combining the sowing density of 2.85×10^(5)plants ha^(-1)with the application of100 mg L^(-1)Pbzwas found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.展开更多
Tree peony(Paeonia suffruticosa Andr.)is a traditional Chinese flower,which prefers cool weather.However,high temperature in summer in the middle and lower reaches of the Yangtze River restricts its growth and develop...Tree peony(Paeonia suffruticosa Andr.)is a traditional Chinese flower,which prefers cool weather.However,high temperature in summer in the middle and lower reaches of the Yangtze River restricts its growth and development.In this study,osmotic regulation,antioxidant enzyme activities,and photosynthetic characteristics of tree peony in response to high-temperature stress were investigated.The results showed that high-temperature stress had destroyed the cell membrane,manifested as the increased relative electrical conductivity and malondialdehyde content.Moreover,high-temperature stress led to excessive accumulation of reactive oxygen species,thereby,activating antioxidant enzyme activities.Also,photosynthetic parameters and chlorophyll fluorescence parameters directly reflected the damage to the photosystem II reflection center under high-temperature stress.In addition,high-temperature stress led to stomatal closure and chloroplast damage.This study revealed the physiological responses of tree peony to high-temperature stress,laying a foundation for the promotion of tree peony in high-temperature areas and the improvement of high-temperature resistance.展开更多
The mechanism of high yield of winter wheat in the field at late growth period was investigated by measuring the photosynthetic characteristics of photosystem Ⅱ (PSⅡ) and xanthophylls cycle, which could provide ph...The mechanism of high yield of winter wheat in the field at late growth period was investigated by measuring the photosynthetic characteristics of photosystem Ⅱ (PSⅡ) and xanthophylls cycle, which could provide physiological reference for breeding. Weimai 8 (W8), a super high yield cultivar, and Lumai 14 (L14), a control cultivar were object. The photosynthetic rate (Pn), parameters of chlorophyll fluorescence and chlorophyll content were measured. The Pn, maximum photochemical efficiency of PSII (Fv/Fm), quantum yield of PSII electron transport (ΦPSⅡ), efficiency of excitation energy capture by open PSII reaction centers (Fv'/Fm'), and photochemical quenching coefficient (qP) were higher in Weimai 8 compared to that in Lumai 14, a commercial high yield cultivar. Furthermore, Weirnai 8 showed a lower non- photochemical quenching coefficient and a lower de-epoxidized ratio of the xanthophyll cycle pigments than of Lumai 14 at late growth period. At mature stage, chlorophyll content of different leaves decreased both in Weimai 8 and Lumai 14. Chlorophyll content in flag, second and third leaf from the top of plant decreased more in Lumai 14 than in Weimai 8. These results suggested that Weimai 8 had more antenna pigments to absorb light energy, and had higher photosynthetic capability and photochemical efficiency of PSⅡ. The yield of Weimai 8 was also higher than that of Lumai 14.展开更多
To investigate the effects of formulated fertilizer synergist on the drought tolerance in rice, pot experiment was conducted to analyze the photosynthetic characteristics and the accumulation of abscisic acid (ABA) ...To investigate the effects of formulated fertilizer synergist on the drought tolerance in rice, pot experiment was conducted to analyze the photosynthetic characteristics and the accumulation of abscisic acid (ABA) and proline in middle-season rice variety Peiliangyou 93. The synergist could improve the net photosynthetic rate, and coordination between the water loss and the CO2 absorption as well as reduce the harmful effect on photosynthetic process under drought conditions. Under drought, the ABA accumulated massively both in roots and leaves, while the ABA content in roots was far higher than that in leaves. The results indicate that synergist could increase the ABA accumulation, but reduce the proline accumulation in rice plant under drought.展开更多
The photosynthetic characteristics and ultrastructure of chloroplast of cucumber in solar-greenhouse were studied. The result showed that the photosynthetic rate (Pn), photosyntheticability (A350), carboxylation effic...The photosynthetic characteristics and ultrastructure of chloroplast of cucumber in solar-greenhouse were studied. The result showed that the photosynthetic rate (Pn), photosyntheticability (A350), carboxylation efficiency, light saturation point and light compensation pointall declined remarkably under low light density, indicating that the photosynthetic characteristicsof cucumber were closely related to light environment. Under low light density, the minimalfluorescence (Fo), alterable fluorescence (Fv), photochemical efficiency of PSⅡ(Fv/Fm), steadyfluorescence in light (Fs), maximal fluorescence (Fm) and actual efficiency of PSⅡ(φPSⅡ)etcincreased, indicating that the photochemical activity and efficiency for solar energy transformationenhanced, thus the light proportion used to electron transport also increased. The chlorophylla, b, a/b and carotenoid of shading leaves decreased. However, the depressed extent of Chl a andChl a/b were obviously larger than that of Chl b. The number of chloroplast and starch grainin cucumber leaves descended, but that of grana and lamella increased as a shaded result. Thesize of chloroplast and starch grain of shading leaves minished.展开更多
Using 18 indica rice varieties with different panicle weight, the photosynthetic characteristics and assimilate's accumulation and transformation in heavy panicle type of rice(HPT)were studied. The results showed ...Using 18 indica rice varieties with different panicle weight, the photosynthetic characteristics and assimilate's accumulation and transformation in heavy panicle type of rice(HPT)were studied. The results showed that the net photosynthetic rate of the flag leaf in HPT after heading was obviously higher than that in medium panicle type(MPT)and light panicle type(LPT). The reason for the high net photosynthetic rate in HPT was the increase of Rubisco activities and chlorophyll content, and keeping high assimilate ability to CO2 under high and low light intensity, high temperature and low CO2 content, and light midday depression and wide adaptability to environmental conditions. The high net photosynthetic rate of HPT might be also the results of its excellent stomatal characteristics and higher total quantity of stomatal opening degrees(stomatal density X stomatal opening degrees). There was a large amount of dry matter production after heading and obvious high assimilate's transformation to panicle in HPT.展开更多
We compared the photosynthetic characteristics in relation to yield of two F1 cotton hybrids(Shiza 2-F1 and Xinluzao 43-F1), their parental lines(NT2, H2 and 4-14) and their F2 descendants at different growth and ...We compared the photosynthetic characteristics in relation to yield of two F1 cotton hybrids(Shiza 2-F1 and Xinluzao 43-F1), their parental lines(NT2, H2 and 4-14) and their F2 descendants at different growth and development stages. The two F1 exhibited heterobeltiosis in net photosynthetic rate(Pn) by 8.1-52.1%, canopy apparent photosynthetic rate(CAP) by 8.2-57.6% and canopy respiration rate(CR) by 3.0-78.7% during the growing season. They also exhibited mid-parent heterosis by 2.0-5.2% in leaf chlorophyll content(SPAD) during the late growth and development stages. Regression analysis showed that both parents contributed to increase in Pn, SPAD and CAP in the F1. A low CR in the F1 matched a low CR of the parental line. Photosynthetic characteristics in the F2 were mainly dependent upon the magnitude and degeneration rate of the F1. Mid-parent heterosis in CAP and in CR during the late growth and development stage reduced the degeneration of the F2. Average dry matter accumulation was 10.7-34.7% higher in the parental lines of Xinluzao 43-F1 than in the parental lines of Shiza 2-F1. Heterobeltiosis in dry matter accumulation was 7.0-23.1% greater for Xinluzao 43-F1 than for Shiza 2-F1. Dry matter accumulation in the F1 was affected by either the dry matter accumulation of parents or heterobeltiosis. Dry matter accumulation in the F2 was mainly influenced by dry matter accumulation in the F1. The yields of the two F1 were 39.1-46.3% higher than their respective parents and 26.4-45.9% higher than that of the conventional cultivar Xinluzao 33. The yields of the two F2 were 9.2-12.8% higher than the parents and 14.9-27.4% higher than that of Xinluzao 33. The photosynthetic production and yield of the F1 and F2 were higher than that of their parents. The increases in Pn and CAP of the F1 and F2 were dependent on the photosynthetic characteristics of their parents. It is thus concluded that the photosynthetic performance, light use efficiency and yield of the F1 can be improved by using at least one parent with low CR, but high CAP, Pn and SPAD. This strategy might also improve the value of the F2.展开更多
The active compounds in herb drugs are mainly secondary metabolites, which are greatly influenced by external conditions. Particularly, light intensity has a great influence on the photosynthesis and accumulation of s...The active compounds in herb drugs are mainly secondary metabolites, which are greatly influenced by external conditions. Particularly, light intensity has a great influence on the photosynthesis and accumulation of secondary metabolites. In this study, the light intensity was changed, and the influence of the light intensity on leaf photosynthetic characteristics, antioxidant enzyme activity and flavone contents of Lithocarpus litseifoliusp (Hance) Chun. was discussed. The results showed that (1) L. litseifolius is a typical heliophyte. As the light intensity decreased, the contents of chlorophyll a (Chl a), chlorophyll b (Chl b) and total chlorophyll (Chl a + b) all increased. However, the Chl a/b ratio gradually decreased. The daily variation of net photosynthetic rate changed from a double-peak curve under natural light to single-peak curve under 20% full light two shading nets. (2) As the light intensity decreased, the SOD and POD activities and the soluble proteins content decreased in the leaves. In contrast, the malondialdehyde content increased. (3) The flavone content was the highest in leaves at one shading nets 60% of full light, and the lowest occurred in leaves at two shading nets 20% of full light. A comprehensive analysis indicated that an appropriate shading could induce shade tolerance in the leaves of L. litseifolius, which promoted the accumulation of flavonoids. L. litseifolius should be planted in the lower position of sunny slope or the upper position of shady slope to increase the content of flavone in the leaves.展开更多
Alpine meadow plants,adapted to humid and cold environments,are highly sensitive to environmental factors such as drought and heat.However,the physiological responses of individual alpine meadow species to drought and...Alpine meadow plants,adapted to humid and cold environments,are highly sensitive to environmental factors such as drought and heat.However,the physiological responses of individual alpine meadow species to drought and heat stress remain unclear.In this study,four representative species of typical functional groups in an alpine meadow of the Qinghai-Tibet Plateau were selected as experimental materials.Heat(H1,H2),drought(D1,D2),and combined stress(D1H1,D2H2)treatments were implemented to reveal the biomass and physiological characteristics’response to a constant drought and heat environment.Our results showed that the leaf water content(LWC)of Kobresia humilis and Poa annua increased significantly under heat stress and the compound stress(P<0.05).The effect of a single factor on LWC was greater than that of multiple factors.The aboveground biomass(AGB)of Oxytropis ochrocephala and Saussurea pulchra decreased significantly under compound stress(P<0.05).The response patterns of the net photosynthetic rate(Pn)and transpiration rate(Tr)of K.humilis and P.annua under various stress treatments were similar;as were those of O.ochrocephala and S.pulchra.The stomatal conductance(Gs)variation in K.humilis,P.annua,O.ochrocephala,and S.pulchra were the same under three kinds of stress treatments.The photosynthetic characteristics were more sensitive to the effects of composite than those of single factors.The drought×heat×species treatment had a significant influence on various indexes except on height(Ht)and the belowground biomass(BGB)(P<0.01).Within a certain range,daytime temperature(DT)promoted the Ht and increased the LWC of the plants,while it inhibited their AGB and intercellular CO2 concentration(Ci).The Pn,Tr,and Gs were more sensitive to soil moisture than to DT.The results help improve understanding of the physiological response regularity of representative alpine meadow plant species to continuous drought and high temperature conditions at the species level,and provided experimental data and theoretical basis to identify the decisive factors of stress response.展开更多
Blue and red light are spectral wavelengths more effective for plants. The effects of different ratios of red and blue light (R/B=2, R/B=4, R/B=8, R/B=12) provided by LEDs on morphology and photosynthetic characteri...Blue and red light are spectral wavelengths more effective for plants. The effects of different ratios of red and blue light (R/B=2, R/B=4, R/B=8, R/B=12) provided by LEDs on morphology and photosynthetic characteristics of tomato seedlings were studied. The results showed that plant height, stem diameter, fresh weight, dry weight, seedling index and G value increased with the increase of R/B ratio until 8. On the contrary, SPDA value decreased with the increase of R/B ratio. Photosynthetic characteristics were measured by CO 2 assimilation ( Pn ), stomatal conductance ( gs ) and intracellular CO 2 concentration ( Ci) . Pn and gs decreased with the increase of R/B ratio. Furthermore, similar trend was investigated in photochemical quenching (qP) and electron transport rate (ETR). Results of this study suggest that compared with white LED, appropriate combination of red and blue light can enhance plant growth and photosynthetic characteristics, and the optimal blue/red ratio for tomato growth was R/B=8.展开更多
The leaf photosynthesis and nitrogen(N) translocation in three large-spike lines and control cultivar(Xi'nong 979) of winter wheat(Triticum aestivum L.) were studied in 2010–2011 and 2011–2012. The objectives...The leaf photosynthesis and nitrogen(N) translocation in three large-spike lines and control cultivar(Xi'nong 979) of winter wheat(Triticum aestivum L.) were studied in 2010–2011 and 2011–2012. The objectives of this study were to investigate the differences in the physiological characteristics of large-spike lines and control cultivar and identify the limiting factors that play a role in improving the yield of breeding materials. The average yield, grain number per spike, kernel weight per spike, and 1 000-kernel weight of the large-spike lines were 16.0, 26.8, 42.6, and 15.4%, respectively, significantly higher than those of control. The average photosynthetic rates(Pn) were not significant between the large-spike lines and control cultivar during the active growth period. The average PSII maximum energy conversion efficiency(Fv/Fm), PSII actual quantum efficiency(Ф(PSII)), photochemical quenching coefficient(qP), PSII reaction center activity(Fv′/Fm′) and water-use efficiency(WUE) of the large-spike lines were 1.0, 5.1, 3.6, 0.8, and 43.4%, respectively, higher than those of the control during the active growth stages. The N distribution proportions in different tissues were ranked in the order of grains〉culms+sheathes〉rachis+glumes〉flag leaves〉penultimate leaves〉remain leaves. This study suggested that utilization of the large-spike wheat might be a promising approach to obtain higher grain yield in Northwest China.展开更多
Three F3 hybrids derived from the sterile rice lines Gang 46A, 776A and 2480A and the improved restorer line Shuhui 881 containing maize phosphoenolpyruvate carboxylase (pepc) gene were used to analyze the effect of...Three F3 hybrids derived from the sterile rice lines Gang 46A, 776A and 2480A and the improved restorer line Shuhui 881 containing maize phosphoenolpyruvate carboxylase (pepc) gene were used to analyze the effect of pepc gene on the heterosis and photosynthetic characteristics, while the F3 obtained by crossing Shuhui 881 with the above three sterile lines served as controls. The dynamics of photosynthetic characteristics in leaves of three F1 with pepc gene and their controls were determined at the initial-tillering, maxium-tillering, elongation, initial-heading, heading, maturity stages, and other different times after flag leaf fully expanded. The PEPCase activities of the three F1 with pepc gene increased significantly as compared with control plants during the whole developmental stages. Moreover, the net photosynthesis rate (Pn) also increased to certain extent. The data showed that PEPCase activity was significantly correlated to Pn with a correlation coefficient of 0.6081. The photosynthetic indexes of the three F1 with pepc gene were obviously superior to respective controls in apparent quantum efficiency, light compensation point and carboxylation efficiency, while the CO2 compensation point was lower than that of corresponding control. The Pn of the three F1 with pepc gene at light saturation point and CO2 saturation point was also higher than that of control plants. in addition, the three F1 with pepc gene had an average increase of 37.10% in grain yields per plant in comparison with control plants. The results indicated that the photosynthetic characteristics of hybrid rice containing pepc gene had been improved to some extent due to the introduction of pepc gene.展开更多
common maize synthetic rate( Photosynthetic characteristics were probed by sweet maize, waxy maize, high starch maize and The results revealed that leaf area index (LAI), chlorophyll a content, chlorophyll b cont...common maize synthetic rate( Photosynthetic characteristics were probed by sweet maize, waxy maize, high starch maize and The results revealed that leaf area index (LAI), chlorophyll a content, chlorophyll b content,photo-PR) showed single peak curve at the whole growth stage. The stages of peak were different according to different varieties. NEAUS4 had the lowest peak and while SIDAN 19 had the highest among all stages. Ratio of chlorophyll a to b was low at seedling stage, reached the peak atjointing stage and then declined. SIDAN 19 had the lower level at the last stages.展开更多
In the present study, appropriate nitrogen(N) application mode in Jianghan Plain was explored by investigating the effects of different N applications on the photosynthetic characteristics of flag leaves and nitrogen ...In the present study, appropriate nitrogen(N) application mode in Jianghan Plain was explored by investigating the effects of different N applications on the photosynthetic characteristics of flag leaves and nitrogen use efficiency(NUE) in a wheat cultivar Zhengmai 9023. Nitrogen was top-dressed before sowing, before winter, and during the jointing stage, at different ratios:1:1:0(N1), 1:0:1(N2), 2:1:1(N3), 1:1:1(N4), and 0:0:1(N5), under the same amount of total N(180 kg/hm^2) during the growing season. No nitrogen fertilizer was used in the control(N0). Results showed that the SPAD values and photosynthetic rate(Pn) of different treatments in flag leaves increased initially and then decreased around the anthesis stage. The two indices in N1 and N5 treatments decreased rapidly after flowering, whereas those in N2, N3, and N4 treatments maintained at high levels for a long period after anthesis. Thus, reasonable nitrogen application could retard the decline of SPAD and Pn after anthesis.N4 and N1 treatments showed large dry matter accumulation. In decreasing order of crop yield, the treatments were: N4 >N1 >N3 >N5 >N2 >N0. The effective panicle number and grain number per spike of N2 were significantly lower than those of other treatments, and there was no significant difference among other treatments. No significant correlation was found between nitrogen application and 1 000-grain weight in this experiment. The nitrogen accumulation, agronomic efficiency of nitrogen fertilizer,nitrogen uptake and use efficiency of above-ground parts, nitrogen uptake and use efficiency of grain of N4 treatment were higher than those of other treatments, but the nitrogen harvest index of N4 was at a low level. In summary, N4 treatment is the most suitable nitrogen application mode in wheat after rice.展开更多
With andromonoecious<i><span> Momordica charantia </span></i><span>L.</span><span> </span><span>(bitter gourd) as material, three light qualities</span><s...With andromonoecious<i><span> Momordica charantia </span></i><span>L.</span><span> </span><span>(bitter gourd) as material, three light qualities</span><span> </span><span>(50 μmol·m</span><sup><span style="vertical-align:super;">-2</span></sup><span>·s</span><sup><span style="vertical-align:super;">-1</span></sup><span>) including white LED light</span><span> </span><span>(WL), blue monochromatic light (B,</span><span> </span><span>465 nm), and red monochromatic light (R, 650 nm) were carried out to investigate their effects on seed germination, physiological and biochemical parameters, sex differentiation and photosynthetic characteristics of bitter gourd. The results showed that compared to the WL treatment, the R treatment significantly promoted seed germination, seedling height elongation and soluble sugar content, the B treatment significantly increased seedling stem diameter, reducing sugar content and soluble protein content, the R and B treatments both significantly reduced sucrose content, but their POD activity showed no significant difference. Compared with the R treatment, the B treatment significantly increased the total female flower number and female flower nod ratio in 30 nods of main stems. The study of photosynthetic characteristics found that the R and B treatments could effectively increase the </span><span>stomata</span><span>l conductance (GS) of leaves, significantly improved the net photosynthetic rate</span><span> </span><span>(Pn) compared to the WL treatment, and the effect of the B treatment was better. Compared to the R and WL treatments, the B treatment increased the maximum photosynthetic rate (P</span><sub><span style="vertical-align:sub;">max</span></sub><span>),</span><span> </span><span>apparent quantum efficiency</span><span> </span><span>(AQE) and light saturation point</span><span> </span><span>(LSP), and reduced the dark respiration rate (Rd) and light compensation point</span><span> </span><span>(LCP) of the leaves. Fit light response curves showed that the adaptability and utilization of weak light in bitter gourd were middle or below, but it showed higher adaptability and utilization of strong light. Thus, it suggests that </span><i><span>Momordica charantia</span></i><span> is a typical sun plan with lower Rd. In summary, it is concluded that blue light has a positive effect on the seed germination, seedling growth, sex differentiation and improving the photosynthetic performance, and this will lay the foundation for artificially regulating optimum photosynthesis using specific LEDs wavelength, and help to elucidate the relationship how light quality influences the sex differentiation of plant.</span>展开更多
Based on the investigation of the species and frequency of submerged plants in Nanjishan Wetland of Poyang Lake in the winter of 2013,chlorophyll contents and photosynthetic fluorescence characteristics of the dominan...Based on the investigation of the species and frequency of submerged plants in Nanjishan Wetland of Poyang Lake in the winter of 2013,chlorophyll contents and photosynthetic fluorescence characteristics of the dominant submerged plants were studied using chlorophyll fluorescence imaging method. The results indicate that the major submerged plants of Nanjishan Wetland in Poyang Lake in winter included Hydrilla verticillata,Vallisneria natans,Najas minor,Potamogeton pectinatus,Nymphoides peltatum,Myriophyllum verticillatum and so on,and the dominant species were mainly H. verticillata and V. natans in different submerged plant communities. The chlorophyll content of H. verticillata is higher than that of V.natans,and the photosynthesis intensity of H. verticillata is stronger than that of V. natans. The value of Ca / Cb of H. verticillata is not large,which shows that the light-harvesting capacity of H. verticillata's chlorophyll is considerable in different sampling sites. The highest value of QY-max of V.natans is up to 0. 732,while the lowest value is only 0. 465; the highest value of QY-max of H. verticillata is 0. 677,while the lowest value is 0. 556.All values of QY-max of the submerged plants were lower than 0. 8,which shows that the submerged plants in Nanjishan Wetland of Poyang Lake may be subjected to certain external stress,which indicates that the external stress might cause some damage for the PSII reaction centers.展开更多
Four wheat cultivars were used to study the effects of delayed nitrogen topdressing on population structure, grain yield and photosynthetic characteristics of flag leaves under high-yielding conditions. The results sh...Four wheat cultivars were used to study the effects of delayed nitrogen topdressing on population structure, grain yield and photosynthetic characteristics of flag leaves under high-yielding conditions. The results showed that the nitrogen topdressing delayed from overwintering-turning green stage (N1) to turning green-jointing stage(N2) and jointing-booting stage(N3) decreased ineffective tiller in spring, retarded the decline of green leaf area and chlorophyll content in late life span, promoted photosynthetic ability of flag leaves and significantly increased the grain yield. N3 treatment was suitable for most wheat cultivars except the genotypes with higher single spike productivity and less ears in unit area.展开更多
This study aimed to investigate chlorophyll content and photosynthetic characteristics of 17 pepper inbred lines which were selected independently. The results showed that chlorophyll contents significantly varied amo...This study aimed to investigate chlorophyll content and photosynthetic characteristics of 17 pepper inbred lines which were selected independently. The results showed that chlorophyll contents significantly varied among different inbred lines. To be specific, chlorophyll content of No. 68 inbred line was significantly higher than that of other 14 inbred lines ; chlorophyll content of No. 55 inbred line was signifieandy lower than that of other 15 inbred lines. The chlorophyll content of various inbred lines showed a decreasing order of No. 68 〉 No. 47 〉 No. 66 〉 No. 62 〉 No. 63 〉 No. 60 〉 No. 61 〉 No. 64 〉 No. 56 〉 No. 67 〉 No. 65 〉 No. 48 〉 No. 59 〉 No. 58 〉 No. 57 〉 No. 69 〉 No. 55 ; the photosynthetic rate of various inbred lines showed a decreasing order of No. 68 〉 No. 57 〉 No. 60 〉 No. 48 〉 No. 58 〉 No. 47 〉 No. 62 〉 No. 63 〉 No. 64 〉 No. 65 ; the maximum photesynthetie rate of No. 65 inbred line was significantly lower than other seven inbred lines, while no signifi- cant difference was observed among other nine inbred lines.展开更多
[Objectives]This study was conducted to improve the water use efficiency and fruit quality of citrus,and realize the automatic irrigation and standardized production in citrus orchards.[Methods]With Orah as the resear...[Objectives]This study was conducted to improve the water use efficiency and fruit quality of citrus,and realize the automatic irrigation and standardized production in citrus orchards.[Methods]With Orah as the research object,the effects of intelligent irrigation management in citrus orchards on citrus leaf chlorophyll content,photosynthetic characteristics and fruit quality were investigated by comparing with conventional farmer management.[Results]The smart irrigation measure in citrus orchards significantly increased the SPAD value of leaves at the maturation stage of citrus,and simultaneously significantly improved the photosynthetic rate,transpiration rate and stomatal conductance at the flower bud differentiation stage,as well as the photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO_(2) concentration at the maturation stage.However,the effects on the photosynthetic characteristic indexes in the rainy season were not significant.Compared with conventional experience management,the smart irrigation management measure of citrus orchards increased the edible rate and juice rate of citrus by 4.53 and 3.69 percentage points,respectively,and increased soluble solids,total sugar,vitamin C and sugar-acid ratio by 16.75%,20.86%,24.10%and 13.17%,respectively.[Conclusions]The smart irrigation management fully met the water demand for citrus growth due to timely irrigation,significantly improved the photosynthesis indicators of citrus leaves during drought,and significantly improved the quality of citrus.展开更多
基金financed by the National Key Research and Development Program,China(Grant Nos.2022YFE0113400 and 2022YFD1500402)National Natural Science Foundation of China(Grant No.32001466)+3 种基金Scientific and Technological Innovation Fund of Carbon Emissions Peak and Neutrality of Jiangsu Provincial Department of Science and Technology,China(Grant Nos.BE2022304 and BE2022305)Joints Funds of the National Natural Science Foundation of China(Grant No.U20A2022)Postdoctoral Research Foundation of China(Grant No.2020M671628)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China.
文摘Simultaneous stresses of salinity and drought often coincide during rice-growing seasons in saline lands,primarily due to insufficient water resources and inadequate irrigation facilities.Consequently,combined salinity-drought stress poses a major threat to rice production.In this study,two salinity levels(NS,non-salinity;HS,high salinity)along with three drought treatments(CC,control condition;DJ,drought stress imposed at jointing;DH,drought stress imposed at heading)were performed to investigate their combined influences on leaf photosynthetic characteristics,biomass accumulation,and rice yield formation.Salinity,drought,and their combination led to a shortened growth period from heading to maturity,resulting in a reduced overall growth duration.Grain yield was reduced under both salinity and drought stress,with a more substantial reduction under the combined salinity-drought stress.The combined stress imposed at heading caused greater yield losses in rice compared with the stress imposed at jointing.Additionally,the combined salinity-drought stress induced greater decreases in shoot biomass accumulation from heading to maturity,as well as in shoot biomass and nonstructural carbohydrate(NSC)content in the stem at heading and maturity.However,it increased the harvest index and NSC remobilization reserve.Salinity and drought reduced the leaf area index and SPAD value of flag leaves and weakened the leaf photosynthetic characteristics as indicated by lower photosynthetic rates,transpiration rates,and stomatal conductance.These reductions were more pronounced under the combined stress.Salinity,drought,and especially their combination,decreased the activities of ascorbate peroxidase,catalase,and superoxide dismutase,while increasing the contents of malondialdehyde,hydrogen peroxide,and superoxide radical.Our results indicated a more significant yield loss in rice when subjected to combined salinity-drought stress.The individual and combined stresses of salinity and drought diminished antioxidant enzyme activities,inhibited leaf photosynthetic functions,accelerated leaf senescence,and subsequently lowered assimilate accumulation and grain yield.
基金supported by the National Key Research and Development Program of China(2020YFD1000902)the Shandong Key Research and Development Program(2018YFJH0601-3)+1 种基金the Major Agricultural Applied Technological Innovation Projects in Shandong Province(SD2019ZZ11)the Shandong Modern Agricultural Technology and Industry System(SDAIT-04-01)。
文摘The key to high-yielding peanut cultivation is the optimization of agricultural production practices.Regulating single-seed precise sowing(SSPS)density and paclobutrazol(Pbz)application concentration are effective practices that increase peanut yield by improving plant architecture,lodging resistance,and photosynthetic characteristics.Therefore,we conducted a two-factor field optimization experiment for the sowing density(D1:1.95×10^(5)plants ha^(-1),D52:2.40×10plants ha^(-1),D3:2.85×10^(5)plants ha^(-1),and D4:3.30×10^(5)plants ha^(-1))and Pbzapplication concentration(P0:0 mg L^(-1)and P1:100 mg L^(-1)).The objective was to optimize agricultural production practices and provide a theoretical basis for highyielding peanut cultivation by evaluating the effects of sowing density and Pbzapplication on plant architecture,lodging resistance,photosynthetic characteristics,and yield.The results showed that at the same Pbzapplication concentration,increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity.At the same sowing density,Pbzapplication reduced lodging percentage by decreasing plant height(PH),improving lignin biosynthesis-related enzyme activities,and enhancing stem puncture strength(SPS)and breaking strength(SBS).The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata,resulting in the increase in relative chlorophyll content and net photosynthetic rate(Pn)of leaves.Furthermore,D3P1treatment had the highest peanut yield among all treatments.In summary,the production strategy combining the sowing density of 2.85×10^(5)plants ha^(-1)with the application of100 mg L^(-1)Pbzwas found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.
基金supported by Jiangsu Modern Agricultural Industrial Technology System(JATS[2022]489)Agricultural Science and Technology Independent Innovation Fund of Jiangsu Province(CX(22)3186)+1 种基金Policy Guidance Program of Jiangsu Province-Science and Technology Special Project of Northern Jiangsu Province(SZ-SQ2021041)the Qing Lan Project of Jiangsu Province and High-Level Talent Support Program of Yangzhou University.
文摘Tree peony(Paeonia suffruticosa Andr.)is a traditional Chinese flower,which prefers cool weather.However,high temperature in summer in the middle and lower reaches of the Yangtze River restricts its growth and development.In this study,osmotic regulation,antioxidant enzyme activities,and photosynthetic characteristics of tree peony in response to high-temperature stress were investigated.The results showed that high-temperature stress had destroyed the cell membrane,manifested as the increased relative electrical conductivity and malondialdehyde content.Moreover,high-temperature stress led to excessive accumulation of reactive oxygen species,thereby,activating antioxidant enzyme activities.Also,photosynthetic parameters and chlorophyll fluorescence parameters directly reflected the damage to the photosystem II reflection center under high-temperature stress.In addition,high-temperature stress led to stomatal closure and chloroplast damage.This study revealed the physiological responses of tree peony to high-temperature stress,laying a foundation for the promotion of tree peony in high-temperature areas and the improvement of high-temperature resistance.
基金supported by the Key Project of Shandong Agriculture: Breeding Technology Research of Super Wheat for High Yield and High Qulity, China([2006]6), the Opening Foundation of the State Key Laboratory of Crop Biology, China (2008KF03)the Postdoctor Innovative Foundation of Shandong Province, China (200802009)+2 种基金the National Basic Re-search of China (973 Program, 2009CB118500)the National Natural Science Foundation of China(30871458)the Program for Changjiang Scholarsand Innovative Research Team in University, China(IRT0635)
文摘The mechanism of high yield of winter wheat in the field at late growth period was investigated by measuring the photosynthetic characteristics of photosystem Ⅱ (PSⅡ) and xanthophylls cycle, which could provide physiological reference for breeding. Weimai 8 (W8), a super high yield cultivar, and Lumai 14 (L14), a control cultivar were object. The photosynthetic rate (Pn), parameters of chlorophyll fluorescence and chlorophyll content were measured. The Pn, maximum photochemical efficiency of PSII (Fv/Fm), quantum yield of PSII electron transport (ΦPSⅡ), efficiency of excitation energy capture by open PSII reaction centers (Fv'/Fm'), and photochemical quenching coefficient (qP) were higher in Weimai 8 compared to that in Lumai 14, a commercial high yield cultivar. Furthermore, Weirnai 8 showed a lower non- photochemical quenching coefficient and a lower de-epoxidized ratio of the xanthophyll cycle pigments than of Lumai 14 at late growth period. At mature stage, chlorophyll content of different leaves decreased both in Weimai 8 and Lumai 14. Chlorophyll content in flag, second and third leaf from the top of plant decreased more in Lumai 14 than in Weimai 8. These results suggested that Weimai 8 had more antenna pigments to absorb light energy, and had higher photosynthetic capability and photochemical efficiency of PSⅡ. The yield of Weimai 8 was also higher than that of Lumai 14.
文摘To investigate the effects of formulated fertilizer synergist on the drought tolerance in rice, pot experiment was conducted to analyze the photosynthetic characteristics and the accumulation of abscisic acid (ABA) and proline in middle-season rice variety Peiliangyou 93. The synergist could improve the net photosynthetic rate, and coordination between the water loss and the CO2 absorption as well as reduce the harmful effect on photosynthetic process under drought conditions. Under drought, the ABA accumulated massively both in roots and leaves, while the ABA content in roots was far higher than that in leaves. The results indicate that synergist could increase the ABA accumulation, but reduce the proline accumulation in rice plant under drought.
文摘The photosynthetic characteristics and ultrastructure of chloroplast of cucumber in solar-greenhouse were studied. The result showed that the photosynthetic rate (Pn), photosyntheticability (A350), carboxylation efficiency, light saturation point and light compensation pointall declined remarkably under low light density, indicating that the photosynthetic characteristicsof cucumber were closely related to light environment. Under low light density, the minimalfluorescence (Fo), alterable fluorescence (Fv), photochemical efficiency of PSⅡ(Fv/Fm), steadyfluorescence in light (Fs), maximal fluorescence (Fm) and actual efficiency of PSⅡ(φPSⅡ)etcincreased, indicating that the photochemical activity and efficiency for solar energy transformationenhanced, thus the light proportion used to electron transport also increased. The chlorophylla, b, a/b and carotenoid of shading leaves decreased. However, the depressed extent of Chl a andChl a/b were obviously larger than that of Chl b. The number of chloroplast and starch grainin cucumber leaves descended, but that of grana and lamella increased as a shaded result. Thesize of chloroplast and starch grain of shading leaves minished.
文摘Using 18 indica rice varieties with different panicle weight, the photosynthetic characteristics and assimilate's accumulation and transformation in heavy panicle type of rice(HPT)were studied. The results showed that the net photosynthetic rate of the flag leaf in HPT after heading was obviously higher than that in medium panicle type(MPT)and light panicle type(LPT). The reason for the high net photosynthetic rate in HPT was the increase of Rubisco activities and chlorophyll content, and keeping high assimilate ability to CO2 under high and low light intensity, high temperature and low CO2 content, and light midday depression and wide adaptability to environmental conditions. The high net photosynthetic rate of HPT might be also the results of its excellent stomatal characteristics and higher total quantity of stomatal opening degrees(stomatal density X stomatal opening degrees). There was a large amount of dry matter production after heading and obvious high assimilate's transformation to panicle in HPT.
基金the National Natural Science Foundation of China(U1203283,31060176)the Key Technologies R&D Program of China during the 11th Five-Year Plan period(2007BAD44B07)
文摘We compared the photosynthetic characteristics in relation to yield of two F1 cotton hybrids(Shiza 2-F1 and Xinluzao 43-F1), their parental lines(NT2, H2 and 4-14) and their F2 descendants at different growth and development stages. The two F1 exhibited heterobeltiosis in net photosynthetic rate(Pn) by 8.1-52.1%, canopy apparent photosynthetic rate(CAP) by 8.2-57.6% and canopy respiration rate(CR) by 3.0-78.7% during the growing season. They also exhibited mid-parent heterosis by 2.0-5.2% in leaf chlorophyll content(SPAD) during the late growth and development stages. Regression analysis showed that both parents contributed to increase in Pn, SPAD and CAP in the F1. A low CR in the F1 matched a low CR of the parental line. Photosynthetic characteristics in the F2 were mainly dependent upon the magnitude and degeneration rate of the F1. Mid-parent heterosis in CAP and in CR during the late growth and development stage reduced the degeneration of the F2. Average dry matter accumulation was 10.7-34.7% higher in the parental lines of Xinluzao 43-F1 than in the parental lines of Shiza 2-F1. Heterobeltiosis in dry matter accumulation was 7.0-23.1% greater for Xinluzao 43-F1 than for Shiza 2-F1. Dry matter accumulation in the F1 was affected by either the dry matter accumulation of parents or heterobeltiosis. Dry matter accumulation in the F2 was mainly influenced by dry matter accumulation in the F1. The yields of the two F1 were 39.1-46.3% higher than their respective parents and 26.4-45.9% higher than that of the conventional cultivar Xinluzao 33. The yields of the two F2 were 9.2-12.8% higher than the parents and 14.9-27.4% higher than that of Xinluzao 33. The photosynthetic production and yield of the F1 and F2 were higher than that of their parents. The increases in Pn and CAP of the F1 and F2 were dependent on the photosynthetic characteristics of their parents. It is thus concluded that the photosynthetic performance, light use efficiency and yield of the F1 can be improved by using at least one parent with low CR, but high CAP, Pn and SPAD. This strategy might also improve the value of the F2.
文摘The active compounds in herb drugs are mainly secondary metabolites, which are greatly influenced by external conditions. Particularly, light intensity has a great influence on the photosynthesis and accumulation of secondary metabolites. In this study, the light intensity was changed, and the influence of the light intensity on leaf photosynthetic characteristics, antioxidant enzyme activity and flavone contents of Lithocarpus litseifoliusp (Hance) Chun. was discussed. The results showed that (1) L. litseifolius is a typical heliophyte. As the light intensity decreased, the contents of chlorophyll a (Chl a), chlorophyll b (Chl b) and total chlorophyll (Chl a + b) all increased. However, the Chl a/b ratio gradually decreased. The daily variation of net photosynthetic rate changed from a double-peak curve under natural light to single-peak curve under 20% full light two shading nets. (2) As the light intensity decreased, the SOD and POD activities and the soluble proteins content decreased in the leaves. In contrast, the malondialdehyde content increased. (3) The flavone content was the highest in leaves at one shading nets 60% of full light, and the lowest occurred in leaves at two shading nets 20% of full light. A comprehensive analysis indicated that an appropriate shading could induce shade tolerance in the leaves of L. litseifolius, which promoted the accumulation of flavonoids. L. litseifolius should be planted in the lower position of sunny slope or the upper position of shady slope to increase the content of flavone in the leaves.
基金supported by the National Natural Science Foundation of China (31672475)Natural Science Foundation of Qinghai Province (2019-ZJ908)+1 种基金National Key Research and Development Program of China (2016YFC0501901)the Second Comprehensive Scientific Investigation of the Tibetan Plateau (2019QZKK0302)
文摘Alpine meadow plants,adapted to humid and cold environments,are highly sensitive to environmental factors such as drought and heat.However,the physiological responses of individual alpine meadow species to drought and heat stress remain unclear.In this study,four representative species of typical functional groups in an alpine meadow of the Qinghai-Tibet Plateau were selected as experimental materials.Heat(H1,H2),drought(D1,D2),and combined stress(D1H1,D2H2)treatments were implemented to reveal the biomass and physiological characteristics’response to a constant drought and heat environment.Our results showed that the leaf water content(LWC)of Kobresia humilis and Poa annua increased significantly under heat stress and the compound stress(P<0.05).The effect of a single factor on LWC was greater than that of multiple factors.The aboveground biomass(AGB)of Oxytropis ochrocephala and Saussurea pulchra decreased significantly under compound stress(P<0.05).The response patterns of the net photosynthetic rate(Pn)and transpiration rate(Tr)of K.humilis and P.annua under various stress treatments were similar;as were those of O.ochrocephala and S.pulchra.The stomatal conductance(Gs)variation in K.humilis,P.annua,O.ochrocephala,and S.pulchra were the same under three kinds of stress treatments.The photosynthetic characteristics were more sensitive to the effects of composite than those of single factors.The drought×heat×species treatment had a significant influence on various indexes except on height(Ht)and the belowground biomass(BGB)(P<0.01).Within a certain range,daytime temperature(DT)promoted the Ht and increased the LWC of the plants,while it inhibited their AGB and intercellular CO2 concentration(Ci).The Pn,Tr,and Gs were more sensitive to soil moisture than to DT.The results help improve understanding of the physiological response regularity of representative alpine meadow plant species to continuous drought and high temperature conditions at the species level,and provided experimental data and theoretical basis to identify the decisive factors of stress response.
基金Supported by Shanghai Science and Technology Commission Project,China(14DZ1206303)National Key Technology R&D Program(2014BAD05B05-05)Shanghai Agriculture Applied Technology Development Program,China(Grant No.20170201)
文摘Blue and red light are spectral wavelengths more effective for plants. The effects of different ratios of red and blue light (R/B=2, R/B=4, R/B=8, R/B=12) provided by LEDs on morphology and photosynthetic characteristics of tomato seedlings were studied. The results showed that plant height, stem diameter, fresh weight, dry weight, seedling index and G value increased with the increase of R/B ratio until 8. On the contrary, SPDA value decreased with the increase of R/B ratio. Photosynthetic characteristics were measured by CO 2 assimilation ( Pn ), stomatal conductance ( gs ) and intracellular CO 2 concentration ( Ci) . Pn and gs decreased with the increase of R/B ratio. Furthermore, similar trend was investigated in photochemical quenching (qP) and electron transport rate (ETR). Results of this study suggest that compared with white LED, appropriate combination of red and blue light can enhance plant growth and photosynthetic characteristics, and the optimal blue/red ratio for tomato growth was R/B=8.
基金financially supported by the National Natural Science Foundation of China (31370425, 31501276)the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2015BAD22B01)
文摘The leaf photosynthesis and nitrogen(N) translocation in three large-spike lines and control cultivar(Xi'nong 979) of winter wheat(Triticum aestivum L.) were studied in 2010–2011 and 2011–2012. The objectives of this study were to investigate the differences in the physiological characteristics of large-spike lines and control cultivar and identify the limiting factors that play a role in improving the yield of breeding materials. The average yield, grain number per spike, kernel weight per spike, and 1 000-kernel weight of the large-spike lines were 16.0, 26.8, 42.6, and 15.4%, respectively, significantly higher than those of control. The average photosynthetic rates(Pn) were not significant between the large-spike lines and control cultivar during the active growth period. The average PSII maximum energy conversion efficiency(Fv/Fm), PSII actual quantum efficiency(Ф(PSII)), photochemical quenching coefficient(qP), PSII reaction center activity(Fv′/Fm′) and water-use efficiency(WUE) of the large-spike lines were 1.0, 5.1, 3.6, 0.8, and 43.4%, respectively, higher than those of the control during the active growth stages. The N distribution proportions in different tissues were ranked in the order of grains〉culms+sheathes〉rachis+glumes〉flag leaves〉penultimate leaves〉remain leaves. This study suggested that utilization of the large-spike wheat might be a promising approach to obtain higher grain yield in Northwest China.
文摘Three F3 hybrids derived from the sterile rice lines Gang 46A, 776A and 2480A and the improved restorer line Shuhui 881 containing maize phosphoenolpyruvate carboxylase (pepc) gene were used to analyze the effect of pepc gene on the heterosis and photosynthetic characteristics, while the F3 obtained by crossing Shuhui 881 with the above three sterile lines served as controls. The dynamics of photosynthetic characteristics in leaves of three F1 with pepc gene and their controls were determined at the initial-tillering, maxium-tillering, elongation, initial-heading, heading, maturity stages, and other different times after flag leaf fully expanded. The PEPCase activities of the three F1 with pepc gene increased significantly as compared with control plants during the whole developmental stages. Moreover, the net photosynthesis rate (Pn) also increased to certain extent. The data showed that PEPCase activity was significantly correlated to Pn with a correlation coefficient of 0.6081. The photosynthetic indexes of the three F1 with pepc gene were obviously superior to respective controls in apparent quantum efficiency, light compensation point and carboxylation efficiency, while the CO2 compensation point was lower than that of corresponding control. The Pn of the three F1 with pepc gene at light saturation point and CO2 saturation point was also higher than that of control plants. in addition, the three F1 with pepc gene had an average increase of 37.10% in grain yields per plant in comparison with control plants. The results indicated that the photosynthetic characteristics of hybrid rice containing pepc gene had been improved to some extent due to the introduction of pepc gene.
文摘common maize synthetic rate( Photosynthetic characteristics were probed by sweet maize, waxy maize, high starch maize and The results revealed that leaf area index (LAI), chlorophyll a content, chlorophyll b content,photo-PR) showed single peak curve at the whole growth stage. The stages of peak were different according to different varieties. NEAUS4 had the lowest peak and while SIDAN 19 had the highest among all stages. Ratio of chlorophyll a to b was low at seedling stage, reached the peak atjointing stage and then declined. SIDAN 19 had the lower level at the last stages.
基金Supported by the National Natural Science Foundation of China (31371580)the Key Research and Development Projects of Ministry of Science and Technology of the People’s Republic of China during the 13th-five Year Plan Period (2016YFD0300107)
文摘In the present study, appropriate nitrogen(N) application mode in Jianghan Plain was explored by investigating the effects of different N applications on the photosynthetic characteristics of flag leaves and nitrogen use efficiency(NUE) in a wheat cultivar Zhengmai 9023. Nitrogen was top-dressed before sowing, before winter, and during the jointing stage, at different ratios:1:1:0(N1), 1:0:1(N2), 2:1:1(N3), 1:1:1(N4), and 0:0:1(N5), under the same amount of total N(180 kg/hm^2) during the growing season. No nitrogen fertilizer was used in the control(N0). Results showed that the SPAD values and photosynthetic rate(Pn) of different treatments in flag leaves increased initially and then decreased around the anthesis stage. The two indices in N1 and N5 treatments decreased rapidly after flowering, whereas those in N2, N3, and N4 treatments maintained at high levels for a long period after anthesis. Thus, reasonable nitrogen application could retard the decline of SPAD and Pn after anthesis.N4 and N1 treatments showed large dry matter accumulation. In decreasing order of crop yield, the treatments were: N4 >N1 >N3 >N5 >N2 >N0. The effective panicle number and grain number per spike of N2 were significantly lower than those of other treatments, and there was no significant difference among other treatments. No significant correlation was found between nitrogen application and 1 000-grain weight in this experiment. The nitrogen accumulation, agronomic efficiency of nitrogen fertilizer,nitrogen uptake and use efficiency of above-ground parts, nitrogen uptake and use efficiency of grain of N4 treatment were higher than those of other treatments, but the nitrogen harvest index of N4 was at a low level. In summary, N4 treatment is the most suitable nitrogen application mode in wheat after rice.
文摘With andromonoecious<i><span> Momordica charantia </span></i><span>L.</span><span> </span><span>(bitter gourd) as material, three light qualities</span><span> </span><span>(50 μmol·m</span><sup><span style="vertical-align:super;">-2</span></sup><span>·s</span><sup><span style="vertical-align:super;">-1</span></sup><span>) including white LED light</span><span> </span><span>(WL), blue monochromatic light (B,</span><span> </span><span>465 nm), and red monochromatic light (R, 650 nm) were carried out to investigate their effects on seed germination, physiological and biochemical parameters, sex differentiation and photosynthetic characteristics of bitter gourd. The results showed that compared to the WL treatment, the R treatment significantly promoted seed germination, seedling height elongation and soluble sugar content, the B treatment significantly increased seedling stem diameter, reducing sugar content and soluble protein content, the R and B treatments both significantly reduced sucrose content, but their POD activity showed no significant difference. Compared with the R treatment, the B treatment significantly increased the total female flower number and female flower nod ratio in 30 nods of main stems. The study of photosynthetic characteristics found that the R and B treatments could effectively increase the </span><span>stomata</span><span>l conductance (GS) of leaves, significantly improved the net photosynthetic rate</span><span> </span><span>(Pn) compared to the WL treatment, and the effect of the B treatment was better. Compared to the R and WL treatments, the B treatment increased the maximum photosynthetic rate (P</span><sub><span style="vertical-align:sub;">max</span></sub><span>),</span><span> </span><span>apparent quantum efficiency</span><span> </span><span>(AQE) and light saturation point</span><span> </span><span>(LSP), and reduced the dark respiration rate (Rd) and light compensation point</span><span> </span><span>(LCP) of the leaves. Fit light response curves showed that the adaptability and utilization of weak light in bitter gourd were middle or below, but it showed higher adaptability and utilization of strong light. Thus, it suggests that </span><i><span>Momordica charantia</span></i><span> is a typical sun plan with lower Rd. In summary, it is concluded that blue light has a positive effect on the seed germination, seedling growth, sex differentiation and improving the photosynthetic performance, and this will lay the foundation for artificially regulating optimum photosynthesis using specific LEDs wavelength, and help to elucidate the relationship how light quality influences the sex differentiation of plant.</span>
基金Supported by the National Natural Science Foundation of China(41161035,41461042)National Key Technology R&D Program in the 12th Five-Year Plan of China(2011BAC13B02)Key Technology R&D Program of Jiangxi Province,China(20133BBG70005)
文摘Based on the investigation of the species and frequency of submerged plants in Nanjishan Wetland of Poyang Lake in the winter of 2013,chlorophyll contents and photosynthetic fluorescence characteristics of the dominant submerged plants were studied using chlorophyll fluorescence imaging method. The results indicate that the major submerged plants of Nanjishan Wetland in Poyang Lake in winter included Hydrilla verticillata,Vallisneria natans,Najas minor,Potamogeton pectinatus,Nymphoides peltatum,Myriophyllum verticillatum and so on,and the dominant species were mainly H. verticillata and V. natans in different submerged plant communities. The chlorophyll content of H. verticillata is higher than that of V.natans,and the photosynthesis intensity of H. verticillata is stronger than that of V. natans. The value of Ca / Cb of H. verticillata is not large,which shows that the light-harvesting capacity of H. verticillata's chlorophyll is considerable in different sampling sites. The highest value of QY-max of V.natans is up to 0. 732,while the lowest value is only 0. 465; the highest value of QY-max of H. verticillata is 0. 677,while the lowest value is 0. 556.All values of QY-max of the submerged plants were lower than 0. 8,which shows that the submerged plants in Nanjishan Wetland of Poyang Lake may be subjected to certain external stress,which indicates that the external stress might cause some damage for the PSII reaction centers.
基金funded by the National Natural Science Foundation of China(39770445).
文摘Four wheat cultivars were used to study the effects of delayed nitrogen topdressing on population structure, grain yield and photosynthetic characteristics of flag leaves under high-yielding conditions. The results showed that the nitrogen topdressing delayed from overwintering-turning green stage (N1) to turning green-jointing stage(N2) and jointing-booting stage(N3) decreased ineffective tiller in spring, retarded the decline of green leaf area and chlorophyll content in late life span, promoted photosynthetic ability of flag leaves and significantly increased the grain yield. N3 treatment was suitable for most wheat cultivars except the genotypes with higher single spike productivity and less ears in unit area.
基金Supported by vegetable Station of Ningxia Hui Autonomous Region
文摘This study aimed to investigate chlorophyll content and photosynthetic characteristics of 17 pepper inbred lines which were selected independently. The results showed that chlorophyll contents significantly varied among different inbred lines. To be specific, chlorophyll content of No. 68 inbred line was significantly higher than that of other 14 inbred lines ; chlorophyll content of No. 55 inbred line was signifieandy lower than that of other 15 inbred lines. The chlorophyll content of various inbred lines showed a decreasing order of No. 68 〉 No. 47 〉 No. 66 〉 No. 62 〉 No. 63 〉 No. 60 〉 No. 61 〉 No. 64 〉 No. 56 〉 No. 67 〉 No. 65 〉 No. 48 〉 No. 59 〉 No. 58 〉 No. 57 〉 No. 69 〉 No. 55 ; the photosynthetic rate of various inbred lines showed a decreasing order of No. 68 〉 No. 57 〉 No. 60 〉 No. 48 〉 No. 58 〉 No. 47 〉 No. 62 〉 No. 63 〉 No. 64 〉 No. 65 ; the maximum photesynthetie rate of No. 65 inbred line was significantly lower than other seven inbred lines, while no signifi- cant difference was observed among other nine inbred lines.
基金Supported by Guangxi Key Research and Development Project(GK AB1850024)。
文摘[Objectives]This study was conducted to improve the water use efficiency and fruit quality of citrus,and realize the automatic irrigation and standardized production in citrus orchards.[Methods]With Orah as the research object,the effects of intelligent irrigation management in citrus orchards on citrus leaf chlorophyll content,photosynthetic characteristics and fruit quality were investigated by comparing with conventional farmer management.[Results]The smart irrigation measure in citrus orchards significantly increased the SPAD value of leaves at the maturation stage of citrus,and simultaneously significantly improved the photosynthetic rate,transpiration rate and stomatal conductance at the flower bud differentiation stage,as well as the photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO_(2) concentration at the maturation stage.However,the effects on the photosynthetic characteristic indexes in the rainy season were not significant.Compared with conventional experience management,the smart irrigation management measure of citrus orchards increased the edible rate and juice rate of citrus by 4.53 and 3.69 percentage points,respectively,and increased soluble solids,total sugar,vitamin C and sugar-acid ratio by 16.75%,20.86%,24.10%and 13.17%,respectively.[Conclusions]The smart irrigation management fully met the water demand for citrus growth due to timely irrigation,significantly improved the photosynthesis indicators of citrus leaves during drought,and significantly improved the quality of citrus.