To determine the potential impacts of exogenous nitrogen(N)enrichment on distribution and transfer of N in Suaeda salsa marsh in the Yellow River Estuary,the variations of N in plant-soil system during the growing sea...To determine the potential impacts of exogenous nitrogen(N)enrichment on distribution and transfer of N in Suaeda salsa marsh in the Yellow River Estuary,the variations of N in plant-soil system during the growing season were investigated by field N addition experiment.The experiment included four treatments:NN(no N input treatment,0gNm^(−2) yr^(−1)),LN(low N input treatment,3.0 gNm^(−2) yr^(−1)),MN(medium N input treatment,6 gNm^(−2) yr^(−1))and HN(high N input treatment,12 gNm^(−2) yr^(−1)).Results showed that N additions generally increased the contents of total nitrogen(TN),ammonia nitrogen(NH_(4)^(+)-N)and nitrate nitrogen(NO_(3)^(−)-N)in different soil layers and the increasing trend was particularly evident in topsoil.Compared with the NN treatment,the average contents of TN in topsoil in the LN,MN and HN treatments during the growing season increased by 10.85%,30.14%and 43.98%,the mean contents of NH_(4)^(+)-N increased by 8.56%,6.96%and 14.34%,and the average contents of NO_(3)^(−)-N increased by 35.73%,45.99%and 46.66%,respectively.Although exogenous N import did not alter the temporal variation patterns of TN contents in organs,the N transfer and accumulation differed among tissues in different treatments.With increasing N import,both the N stocks in soil and plant showed increasing trend and the values in N addition treatments increased by 9.43%–38.22%and 13.40%–62.20%,respectively.It was worth noting that,compared with other treatments,the S.salsa in the MN treatments was very likely to have special response to N enrichment since not only the period of peak growth was prolonged by about 20 days but also the maximum of TN content in leaves was advanced by approximately one month.This paper found that,as N loading reached MN level in future,the growth rhythm of S.salsa and the accumulation and transference of N in its tissues would be altered significantly,which might generate great impact on the stability and health of S.salsa marsh ecosystem.展开更多
Land use practice significantly affects soil properties. Soil is a major sink for atmospheric carbon, and soil organic carbon (SOC) is considered as an essential indicator of soil quality. The objective of this stud...Land use practice significantly affects soil properties. Soil is a major sink for atmospheric carbon, and soil organic carbon (SOC) is considered as an essential indicator of soil quality. The objective of this study was to assess the effects of N and P applied to Suaeda salsa on biomass production, SOC concentration, labile organic carbon (LOC) concentration, SOC pool and carbon management index (CMI) as well as the effect of the land use practice on soil quality of coastal tidal lands in east coastal region of China. The study provided relevant references for coastal exploitation, tidal land management and related study in other countries and regions. The field experiment was laid out in a randomized complete block design, consisting of four N-fertilization rates (0 (NO), 60 (N1), 120 (N2) and 180 kg ha-1 (N3)), three P-fertilization rates (0 (P0), 70 (P1) and 105 kg ha-~ (P2)) and bare land without vegetation. N and P applied to S. salsa on coastal tidal lands significantly affected biomass production (above-ground biomass and roots), bulk density (Pb), available N and P, SOC, LOC, SOC pool and CMI. Using statistical analysis, significantly interactions in N and P were observed for biomass production and the dominant factor for S. salsa production was N in continuous 2-yr experiments. There were no significant interactions between N and P for SOC concentration, LOC concentration and SOC pool. However, significant interaction was obtained for CMI at the 0-20 cm depth and N played a dominant role in the variation of CMI. There were significant improvements for soil measured attributes and parameters, which suggested that increasing the rates of N and P significantly decreased Pb at the 0-20 cm depth and increased available N and P, SOC, LOC, SOC pool as well as CMI at both the 0-20 and 20-40 cm depth, respectively. By correlation analysis, there were significantly positive correlations between biomass (above- ground biomass and roots) and SOC as well as LOC in 2010 and 2011 across all soil depth, respectively. The treatment with N at 180 kg ha-~ and P at 105 kg ha-1 was superior to the other treatments. The results from the 2-yr continuous experiments indicated that, in short-term, there were a few accumulation of SOC and LOC concentrations by means of N and P application to S. salsa, whereas in the long run, S. salsa with N and P application was recommended for coastal tidal lands because of its great potential of carbon sequestration, improvements of soil nutrition status and promotion of soil quality.展开更多
Extremely saline soils are very harsh environments for the growth and survival of most plant species, however, halophytes can grow well. The underlying mechanism of halophyte to resist high saline is not well understo...Extremely saline soils are very harsh environments for the growth and survival of most plant species, however, halophytes can grow well. The underlying mechanism of halophyte to resist high saline is not well understood by us. This study was conducted at the potash mine near the Lop Nur, China, where the effects of the halophyte Suaeda salsa L. on the saline-alkaline soils and its growth and sustainability were investigated. Four plots(in which the salt encrustation layers were removed), with different soil treatments were evaluated:(1) undisturbed soil, with no additional treatment(T1);(2) the slag soil zone, in which a 40-cm layer of slag was placed on the undisturbed soil surface(T2);(3) slag+sandy soil, in which a 20-cm layer of slag was placed in the lower layer and 20 cm of sandy soil, taken from an area about 70 km away from Lop Nur potash mine, where Tamarix species were growing, was placed in the upper layer(T3); and(4) a 40-cm sandy soil layer taken from the area where Tamarix species were growing was placed on undisturbed soil(T4). Soil nutrient contents increased in the four treatments, but salt content only decreased in the T1 treatment. Salt content in the T4 treatment increased over the two-year period, which may be partly attributed to salt deposition from wind-blown dust within the mine and salt accumulation within the surface soil(0–20 cm) in response to high evaporative demands. The S. salsa plants exhibited greater improvements in growth under the T4 treatment than under the T1, T2, and T3 treatments, which demonstrated that low levels of salinity are beneficial for the growth of this species. The T1 treatment was sustainable because of its low cost and superior soil improvement characteristics. Therefore, S. salsa plants not only reduced soil salinity and increased soil nutrient levels, but also ameliorated the plant growth environment, which would be beneficial for both the ecological restoration of the Lop Nur area and similar areas throughout the world.展开更多
Suaeda salsa is an important local species in the intertidal beach of the Western Pacific coast. However,under the artificial cofferdam and Spartina alterniflora expansion,Suaeda marsh has degraded seriously. Therefor...Suaeda salsa is an important local species in the intertidal beach of the Western Pacific coast. However,under the artificial cofferdam and Spartina alterniflora expansion,Suaeda marsh has degraded seriously. Therefore,using Yancheng Nature Reserve as a case study area,taking ETM+images in 2000,2006 and 2011 as the basic data sources,we revealed the evolution characteristics of Salsa marsh which was impacted. The research results are as follows. From 2000 to 2011,Salsa marsh area in the artificial area tempestuously degraded,decreasing by 87. 158%,more than 22% than those in the natural area. The landscape was fragmentized. Landscape polymerization degree index dropped from 95. 780 to 65. 455,more than 16% than those in the natural area. The mean patch area fell down to 21. 429 ha from 389. 333 ha,more than 11% that in the natural area. Compared to the steady change in natural conditions,the area was reduced by 118. 167 ha/a from 2000 to 2006,while during 2006-2011,it was only 51. 500 ha/a in artificial area. As for spatial change of landscape,in artificial area,the Salsa marsh centroid moved forward to the southeast with 666. 350 m,but that in natural area moved forward to the north with 1 042. 710 m from 2000 to 2006. From 2006 to 2011,the centroid moved forward to east and north respectively. Artificial cofferdam transformed the area into freshwater ecosystem,and meanwhile the freshwater was beneficial to Reed marsh. During 2000 to 2006,in the artificial area,539 ha Salsa marsh controlled by cofferdam transferred into reed marsh and aquaculture ponds,of which the transformation rate was nearly 4% higher than that in natural area. From 2006 to 2011,178 ha Salsa marsh was transferred into reed marsh,the transformation rate was 20% higher than that in natural area. With rapid spreading and strong competition of Spartina species,the coastal wetland has formed the pattern of " Salsa – Spartina marshes". From 2000 to 2006,in artificial area,15. 24% of Salsa marsh was transferred into Spartina marsh,of which the transformation rate was13% higher than that in natural area. And from 2006 to 2011,30. 07% Salsa marsh was replaced by the Spartina marsh in artificial area,the rate was almost 10% higher than that in the natural area.展开更多
The halophyte Suaeda salsa can grow in heavy metal-polluted areas along intertidal zones having high salinity.Since phytochelatins can effectively chelate heavy metals,it was hypothesized that S.salsa possessed a phyt...The halophyte Suaeda salsa can grow in heavy metal-polluted areas along intertidal zones having high salinity.Since phytochelatins can effectively chelate heavy metals,it was hypothesized that S.salsa possessed a phytochelatin synthase(PCS) gene.In the present study,the cDNA of PCS was obtained from S.salsa(designated as SsPCS) using homologous cloning and the rapid amplification of cDNA ends(RACE).A sequence analysis revealed that SsPCS consisted of 1 916 bp nucleotides,encoding a polypeptide of 492 amino acids with one phytochelatin domain and one phytochelatin C domain.A similarity analysis suggested that SsPCS shared up to a 58.6%identity with other PCS proteins and clustered with PCS proteins from eudicots.There was a new kind of metal ion sensor motif in its C-terminal domain.The SsPCS transcript was more highly expressed in elongated and fibered roots and stems(P<0.05) than in leaves.Lead and mercury exposure significantly enhanced the mRNA expression of SsPCS(P<0.05).To the best of our knowledge,SsPCS is the second PCS gene cloned from a halophyte,and it might contain a different metal sensing capability than the first PCS from Thellungiella halophila.This study provided a new view of halophyte PCS genes in heavy metal tolerance.展开更多
Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nit...Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow(Huanghe) River Delta, plant samples were collected from two typical salt marshes(Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China's average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis(P < 0.05), and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences(P > 0.05). Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta.展开更多
The nitrogen(N) biological cycle of the Suaeda salsa marsh ecosystem in the Yellow River estuary was studied during 2008 to 2009.Results showed that soil N had significant seasonal fluctuations and vertical distribu...The nitrogen(N) biological cycle of the Suaeda salsa marsh ecosystem in the Yellow River estuary was studied during 2008 to 2009.Results showed that soil N had significant seasonal fluctuations and vertical distribution.The N/P ratio(15.73±1.77) of S.salsa was less than 16,indicating that plant growth was limited by both N and P.The N absorption coefficient of S.salsa was very low(0.007),while the N utilization and cycle coefficients were high(0.824 and 0.331,respectively).The N turnover among compartments of S.salsa marsh showed that N uptake from aboveground parts and roots were 2.539 and 0.622 g/m2,respectively.The N translocation from aboveground parts to roots and from roots to soil were 2.042 and 0.076 g/m2,respectively.The N translocation from aboveground living bodies to litter was 0.497 g/m2,the annual N return from litter to soil was far less than 0.368 g/m2,and the net N mineralization in topsoil during the growing season was 0.033 g/m2.N was an important limiting factor in S.salsa marsh,and the ecosystem was classified as unstable and vulnerable.S.salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat,and the nutrient enrichment due to N import from the Yellow River estuary would be a potential threat to the S.salsa marsh.Excessive nutrient loading might favor invasive species and induce severe long-term degradation of the ecosystem if human intervention measures were not taken.The N quantitative relationships determined in our study might provide a scientific basis for the establishment of effective measures.展开更多
The C3 halophyte Suaeda salsa was used to investigate the roles of Ca^2+, Ca^2+ channels, and calmodulin (CAM) in betacyanin metabolism. Seeds of S. salsa were cultured in both the dark and light for 3 days. The f...The C3 halophyte Suaeda salsa was used to investigate the roles of Ca^2+, Ca^2+ channels, and calmodulin (CAM) in betacyanin metabolism. Seeds of S. salsa were cultured in both the dark and light for 3 days. The fresh weight and betacyanin content were much higher in S. salsa seedlings formed in the dark than in seedlings formed in the light. The addition of Ca^2+ to the half-strength MS nutrient solution promoted betacyanin accumulation in the dark, whereas Ca^2+ depletion by EGTA suppressed the dark-induced betacyanin accumulation in shoots of S. salsa. The Ca^2+ channel blocker LaCl3 also inhibited dark-induced betacyanin accumulation. The highest activity of CaM and the maximum betacyanin content decreased by 51% and 45%, respectively, in shoots of S. salsa seedlings treated with the potent CaM antagonist chlorpromazine in the dark. Furthermore, the other CaM antagonist N-(6-aminohexyl)-5-chloro-l-naphthalenesulfonamide (W-7) also inhibited the activity of CaM and dark-dependent betacyanin accumulation, whereas its less active structural analog N-(6-aminohexyl)- 1-naphthalenesulfonamide (W-5) had little effect on the responses to dark of S. salsa seedlings. These results suggest that Ca^2+, Ca^2+-regulated ion channels, and CaM play an important role in dark-induced betacyanin accumulation in the shoots of the C3 halophyte S. salsa.展开更多
Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are ...Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are therefore of great importance. We used medium-and high-resolution satellite data, meteorological station data, and site measurement data to analyze changes in the area and spatial distribution of Phragmites australis and Suaeda salsa in the Liaohe Delta Wetland from 1998 to 2017, as well as their growth response to the climate change. The results showed that during 1998–2017, the areas of both P. australis and S. salsa wetlands alternated through periods of decreasing,increasing, and then decreasing trends. The annual change in the area and spatial distribution range of S. salsa fluctuated more than that of P. australis. The annual variation of normalized difference vegetation index(NDVI) in P. australis wetland showed an upward trend from 1998 to 2017. The area of P. australis cover that was improved, unchanged, and decreased accounted for 81.8%, 12.3%, and 5.9%, respectively, of the total area;evaporation and wind speed were the main meteorological factors affecting the NDVI;and contribution rates of the climate change and human activities to the NDVI were 73.2% and 26.8%, respectively. The area with vegetation cover being mainly S.salsa that was improved, unchanged, and decreased accounted for 63.3%, 18.3%, and 18.4%, respectively, of the total area;and no meteorological factors significantly affected the NDVI of S. salsa in the region. The interaction between vegetation growth and meteorological factors may help to explain the increasing trend in vegetation cover.The improvement in wetland vegetation also led to carbon sequestration and an increase in sequestration capacity.展开更多
Aims Pigment composition is an important functional trait that can be affected by environmental factors.the objective of this study was to investigate the effect of soil salinity on pigment composition in Suaeda salsa...Aims Pigment composition is an important functional trait that can be affected by environmental factors.the objective of this study was to investigate the effect of soil salinity on pigment composition in Suaeda salsa by comparing chlorophyll and betacyanin content in the Liaohe estuary wetland,a typical coastal wetland in northeast China.Methods We investigated the plant biomass,percentage of red leaves and pigment content(chlorophyll a,chlorophyll b and betacyanins)in S.salsa in intertidal and supratidal zones of the upper,middle and lower reaches of the Liaohe estuary wetlands.the Na^(+)content of both the soil and plant was also measured.Full analysis of variance and multivariate analysis were used to compare differences in pig-ment content and Na^(+)content between the supratidal and intertidal zones.Important Findings Pigment composition was significantly affected by soil salinity.With increasing soil salinity,the percentage of red leaves was higher in the intertidal zone than in the supratidal zone.In all three reaches,plants had lower chlorophyll a content and higher betacyanin con-tent in the intertidal zone than in the supratidal zone.Compared to chlorophyll a,chlorophyll b was less sensitive to soil salinity.there were no differences in chlorophyll b content between the intertidal and supratidal zones in the upper and lower reaches.Furthermore,pigment composition was associated with both the plant tissue and soil Na^(+)content.Compared to the supratidal zone,the intertidal zone had a higher Na^(+)content in plants.there was a negative rela-tionship between plant chlorophyll content and soil Na^(+)content,but a positive relationship between betacyanin content and soil Na^(+)content.Overall,the results indicated that there might be a trade-off between leaf chlorophyll and betacyanin content in S.salsa to main-tain its growth and survival in high salinity environments.展开更多
Xinjiang is the province with the largest saline-alkali land in China.The growth of halophytes will be stressed when their salt content reaches the threshold.In this study,the pot experiments were conducted and Suaeda...Xinjiang is the province with the largest saline-alkali land in China.The growth of halophytes will be stressed when their salt content reaches the threshold.In this study,the pot experiments were conducted and Suaeda salsa,a typical halophyte,was selected as the object to explore the relationship between growth characteristics and salt content under different soil salinity gradients.Salinity gradients were set according to the maximum soil salinity in the current years of Ebinur Lake Wetland National Nature Reserve(ELWNNR).They were classified using the following threshold values:≤2 g/kg(Control Group),10 g/kg,20 g/kg,30 g/kg,and 40 g/kg.The original spectrum,trilateral position and growth characteristics were used as indexes for analysis.With the increase of soil salt content,the red edge shift occurs first,followed by the blue edge shift.The position of yellow edge,green peak and blue edge were not sensitive to the change of soil salinity.This indicates that the red edge is the best indicator for evaluating plant growth.Compared with the Control Group,when the salt content is less than 10 g/kg,the growth status of plant seems not significantly affected.However,plant growth begins to be stressed when the salt content increases to 20 g/kg,which is a turning point for plant health.The increase of soil salt content can inhibit chlorophyll synthesis and plant growth.Plants begin to die when the salt content reaches 40 g/kg.Therefore,40 g/kg could be regarded as the critical point of salt content which inhibits plant growth.The study also shows that the relationship between plant-height change rate and soil salt content is the most significant,indicating that the plant-height change rate is significantly impacted by soil salt content.展开更多
Suaeda salsa is an annual euhalophyte in estuarine wetlands.Soil properties of wetlands have an important influence on S.salsa growth.Therefore,the soil ecological thresholds is valuable for the restoration of degrade...Suaeda salsa is an annual euhalophyte in estuarine wetlands.Soil properties of wetlands have an important influence on S.salsa growth.Therefore,the soil ecological thresholds is valuable for the restoration of degraded S.salsa wetlands.The objectives of this present study were to analyze the soil physicochemical properties and evaluate the soil ecological thresholds in the typical degraded areas for S.salsa growth.Soil text components became coarser with increased sand contents and less clay contents,as the higher degree of wetland degradation.Meanwhile,the salt contents in different soil depths gradually increased with the increased degree of degradation of wetlands.Evident changes in soil water content,organic matter content,and cations concentrations were not observed,while the concentrations of these factors were higher in the soil layer of 0-10 cm than those in the 20-30 cm.The soil pH in the 0-10 cm soil layer was lower than that in the 20-30 cm.The content of the three available nutrients did not change evidently with the increasing degree of degradation.The optimum thresholds of soil salinity and water content were 7.073-16.613 g/kg and 31.8-63.2%,respectively.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.41371104,41971128)the Award Program for Min River Scholar in Fujian Province(No.Min[2015]31).
文摘To determine the potential impacts of exogenous nitrogen(N)enrichment on distribution and transfer of N in Suaeda salsa marsh in the Yellow River Estuary,the variations of N in plant-soil system during the growing season were investigated by field N addition experiment.The experiment included four treatments:NN(no N input treatment,0gNm^(−2) yr^(−1)),LN(low N input treatment,3.0 gNm^(−2) yr^(−1)),MN(medium N input treatment,6 gNm^(−2) yr^(−1))and HN(high N input treatment,12 gNm^(−2) yr^(−1)).Results showed that N additions generally increased the contents of total nitrogen(TN),ammonia nitrogen(NH_(4)^(+)-N)and nitrate nitrogen(NO_(3)^(−)-N)in different soil layers and the increasing trend was particularly evident in topsoil.Compared with the NN treatment,the average contents of TN in topsoil in the LN,MN and HN treatments during the growing season increased by 10.85%,30.14%and 43.98%,the mean contents of NH_(4)^(+)-N increased by 8.56%,6.96%and 14.34%,and the average contents of NO_(3)^(−)-N increased by 35.73%,45.99%and 46.66%,respectively.Although exogenous N import did not alter the temporal variation patterns of TN contents in organs,the N transfer and accumulation differed among tissues in different treatments.With increasing N import,both the N stocks in soil and plant showed increasing trend and the values in N addition treatments increased by 9.43%–38.22%and 13.40%–62.20%,respectively.It was worth noting that,compared with other treatments,the S.salsa in the MN treatments was very likely to have special response to N enrichment since not only the period of peak growth was prolonged by about 20 days but also the maximum of TN content in leaves was advanced by approximately one month.This paper found that,as N loading reached MN level in future,the growth rhythm of S.salsa and the accumulation and transference of N in its tissues would be altered significantly,which might generate great impact on the stability and health of S.salsa marsh ecosystem.
基金support of the Special Fund for Public-Welfare Industrial (Agriculture) Research of China (200903001)the National Natural Science Foundation of China (41171181,41101199)+1 种基金the Key Technology R&D Program of Jiangsu Province, China (BE2010313)the Prospective Project of Production Education Research Cooperation of Jiangsu Province, China (BY2010013)
文摘Land use practice significantly affects soil properties. Soil is a major sink for atmospheric carbon, and soil organic carbon (SOC) is considered as an essential indicator of soil quality. The objective of this study was to assess the effects of N and P applied to Suaeda salsa on biomass production, SOC concentration, labile organic carbon (LOC) concentration, SOC pool and carbon management index (CMI) as well as the effect of the land use practice on soil quality of coastal tidal lands in east coastal region of China. The study provided relevant references for coastal exploitation, tidal land management and related study in other countries and regions. The field experiment was laid out in a randomized complete block design, consisting of four N-fertilization rates (0 (NO), 60 (N1), 120 (N2) and 180 kg ha-1 (N3)), three P-fertilization rates (0 (P0), 70 (P1) and 105 kg ha-~ (P2)) and bare land without vegetation. N and P applied to S. salsa on coastal tidal lands significantly affected biomass production (above-ground biomass and roots), bulk density (Pb), available N and P, SOC, LOC, SOC pool and CMI. Using statistical analysis, significantly interactions in N and P were observed for biomass production and the dominant factor for S. salsa production was N in continuous 2-yr experiments. There were no significant interactions between N and P for SOC concentration, LOC concentration and SOC pool. However, significant interaction was obtained for CMI at the 0-20 cm depth and N played a dominant role in the variation of CMI. There were significant improvements for soil measured attributes and parameters, which suggested that increasing the rates of N and P significantly decreased Pb at the 0-20 cm depth and increased available N and P, SOC, LOC, SOC pool as well as CMI at both the 0-20 and 20-40 cm depth, respectively. By correlation analysis, there were significantly positive correlations between biomass (above- ground biomass and roots) and SOC as well as LOC in 2010 and 2011 across all soil depth, respectively. The treatment with N at 180 kg ha-~ and P at 105 kg ha-1 was superior to the other treatments. The results from the 2-yr continuous experiments indicated that, in short-term, there were a few accumulation of SOC and LOC concentrations by means of N and P application to S. salsa, whereas in the long run, S. salsa with N and P application was recommended for coastal tidal lands because of its great potential of carbon sequestration, improvements of soil nutrition status and promotion of soil quality.
基金supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences (2017476)the National High-level Personnel Special Support Program+3 种基金Xinjiang Youth Science and Technology Innovation Leader Project (QN2016BS0162)the National Key Research and Development Program (2017YFSF03024105)the National Natural Science Foundation of China (31700423,31300449)the Xinjiang Uygur Autonomous Region Science and Technology Support Project (201433101)
文摘Extremely saline soils are very harsh environments for the growth and survival of most plant species, however, halophytes can grow well. The underlying mechanism of halophyte to resist high saline is not well understood by us. This study was conducted at the potash mine near the Lop Nur, China, where the effects of the halophyte Suaeda salsa L. on the saline-alkaline soils and its growth and sustainability were investigated. Four plots(in which the salt encrustation layers were removed), with different soil treatments were evaluated:(1) undisturbed soil, with no additional treatment(T1);(2) the slag soil zone, in which a 40-cm layer of slag was placed on the undisturbed soil surface(T2);(3) slag+sandy soil, in which a 20-cm layer of slag was placed in the lower layer and 20 cm of sandy soil, taken from an area about 70 km away from Lop Nur potash mine, where Tamarix species were growing, was placed in the upper layer(T3); and(4) a 40-cm sandy soil layer taken from the area where Tamarix species were growing was placed on undisturbed soil(T4). Soil nutrient contents increased in the four treatments, but salt content only decreased in the T1 treatment. Salt content in the T4 treatment increased over the two-year period, which may be partly attributed to salt deposition from wind-blown dust within the mine and salt accumulation within the surface soil(0–20 cm) in response to high evaporative demands. The S. salsa plants exhibited greater improvements in growth under the T4 treatment than under the T1, T2, and T3 treatments, which demonstrated that low levels of salinity are beneficial for the growth of this species. The T1 treatment was sustainable because of its low cost and superior soil improvement characteristics. Therefore, S. salsa plants not only reduced soil salinity and increased soil nutrient levels, but also ameliorated the plant growth environment, which would be beneficial for both the ecological restoration of the Lop Nur area and similar areas throughout the world.
基金Supported by National Natural Science Foundation of China(41771199)Basic Research Project of Jiangsu Province,China(BK20171277)
文摘Suaeda salsa is an important local species in the intertidal beach of the Western Pacific coast. However,under the artificial cofferdam and Spartina alterniflora expansion,Suaeda marsh has degraded seriously. Therefore,using Yancheng Nature Reserve as a case study area,taking ETM+images in 2000,2006 and 2011 as the basic data sources,we revealed the evolution characteristics of Salsa marsh which was impacted. The research results are as follows. From 2000 to 2011,Salsa marsh area in the artificial area tempestuously degraded,decreasing by 87. 158%,more than 22% than those in the natural area. The landscape was fragmentized. Landscape polymerization degree index dropped from 95. 780 to 65. 455,more than 16% than those in the natural area. The mean patch area fell down to 21. 429 ha from 389. 333 ha,more than 11% that in the natural area. Compared to the steady change in natural conditions,the area was reduced by 118. 167 ha/a from 2000 to 2006,while during 2006-2011,it was only 51. 500 ha/a in artificial area. As for spatial change of landscape,in artificial area,the Salsa marsh centroid moved forward to the southeast with 666. 350 m,but that in natural area moved forward to the north with 1 042. 710 m from 2000 to 2006. From 2006 to 2011,the centroid moved forward to east and north respectively. Artificial cofferdam transformed the area into freshwater ecosystem,and meanwhile the freshwater was beneficial to Reed marsh. During 2000 to 2006,in the artificial area,539 ha Salsa marsh controlled by cofferdam transferred into reed marsh and aquaculture ponds,of which the transformation rate was nearly 4% higher than that in natural area. From 2006 to 2011,178 ha Salsa marsh was transferred into reed marsh,the transformation rate was 20% higher than that in natural area. With rapid spreading and strong competition of Spartina species,the coastal wetland has formed the pattern of " Salsa – Spartina marshes". From 2000 to 2006,in artificial area,15. 24% of Salsa marsh was transferred into Spartina marsh,of which the transformation rate was13% higher than that in natural area. And from 2006 to 2011,30. 07% Salsa marsh was replaced by the Spartina marsh in artificial area,the rate was almost 10% higher than that in the natural area.
基金Supported by the 100 Talents Program of the Chinese Academy of Sciencesthe Key Technology R&D Program of Shandong Province(No.2012GGA06032)
文摘The halophyte Suaeda salsa can grow in heavy metal-polluted areas along intertidal zones having high salinity.Since phytochelatins can effectively chelate heavy metals,it was hypothesized that S.salsa possessed a phytochelatin synthase(PCS) gene.In the present study,the cDNA of PCS was obtained from S.salsa(designated as SsPCS) using homologous cloning and the rapid amplification of cDNA ends(RACE).A sequence analysis revealed that SsPCS consisted of 1 916 bp nucleotides,encoding a polypeptide of 492 amino acids with one phytochelatin domain and one phytochelatin C domain.A similarity analysis suggested that SsPCS shared up to a 58.6%identity with other PCS proteins and clustered with PCS proteins from eudicots.There was a new kind of metal ion sensor motif in its C-terminal domain.The SsPCS transcript was more highly expressed in elongated and fibered roots and stems(P<0.05) than in leaves.Lead and mercury exposure significantly enhanced the mRNA expression of SsPCS(P<0.05).To the best of our knowledge,SsPCS is the second PCS gene cloned from a halophyte,and it might contain a different metal sensing capability than the first PCS from Thellungiella halophila.This study provided a new view of halophyte PCS genes in heavy metal tolerance.
基金Under the auspices of National Key R&D Program of China(No.2017YFC0505906)National Natural Science Foundation of China(No.51639001,51379012)Interdiscipline Research Funds of Beijing Normal University
文摘Little information is available on biogenic elements(carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow(Huanghe) River Delta, plant samples were collected from two typical salt marshes(Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China's average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis(P < 0.05), and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences(P > 0.05). Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta.
基金supported by the Innovation Program of the Chinese Academy of Sciences(No.KZCX2YW-223)the National Natural Science Foundation of China(No.40803023,40806048)+2 种基金the Key Program of Natural Science Foundation of Shandong Province(No. ZR2010DZ001)the Talents Foundation of the Chinese Academy of Sciences(No.AJ0809BX-036)the Open Research Foundation of Key Laboratory of China Oceanic Administration for Coast Ecology and Environment(No. 200906)
文摘The nitrogen(N) biological cycle of the Suaeda salsa marsh ecosystem in the Yellow River estuary was studied during 2008 to 2009.Results showed that soil N had significant seasonal fluctuations and vertical distribution.The N/P ratio(15.73±1.77) of S.salsa was less than 16,indicating that plant growth was limited by both N and P.The N absorption coefficient of S.salsa was very low(0.007),while the N utilization and cycle coefficients were high(0.824 and 0.331,respectively).The N turnover among compartments of S.salsa marsh showed that N uptake from aboveground parts and roots were 2.539 and 0.622 g/m2,respectively.The N translocation from aboveground parts to roots and from roots to soil were 2.042 and 0.076 g/m2,respectively.The N translocation from aboveground living bodies to litter was 0.497 g/m2,the annual N return from litter to soil was far less than 0.368 g/m2,and the net N mineralization in topsoil during the growing season was 0.033 g/m2.N was an important limiting factor in S.salsa marsh,and the ecosystem was classified as unstable and vulnerable.S.salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat,and the nutrient enrichment due to N import from the Yellow River estuary would be a potential threat to the S.salsa marsh.Excessive nutrient loading might favor invasive species and induce severe long-term degradation of the ecosystem if human intervention measures were not taken.The N quantitative relationships determined in our study might provide a scientific basis for the establishment of effective measures.
基金Specialized Research Fund for the Doctoral Program of Higher Education(SRFDP,20050445003)Shandong Natural Science Foundation(Z2004D03)Science Foundation of Shandong University of Technology.
文摘The C3 halophyte Suaeda salsa was used to investigate the roles of Ca^2+, Ca^2+ channels, and calmodulin (CAM) in betacyanin metabolism. Seeds of S. salsa were cultured in both the dark and light for 3 days. The fresh weight and betacyanin content were much higher in S. salsa seedlings formed in the dark than in seedlings formed in the light. The addition of Ca^2+ to the half-strength MS nutrient solution promoted betacyanin accumulation in the dark, whereas Ca^2+ depletion by EGTA suppressed the dark-induced betacyanin accumulation in shoots of S. salsa. The Ca^2+ channel blocker LaCl3 also inhibited dark-induced betacyanin accumulation. The highest activity of CaM and the maximum betacyanin content decreased by 51% and 45%, respectively, in shoots of S. salsa seedlings treated with the potent CaM antagonist chlorpromazine in the dark. Furthermore, the other CaM antagonist N-(6-aminohexyl)-5-chloro-l-naphthalenesulfonamide (W-7) also inhibited the activity of CaM and dark-dependent betacyanin accumulation, whereas its less active structural analog N-(6-aminohexyl)- 1-naphthalenesulfonamide (W-5) had little effect on the responses to dark of S. salsa seedlings. These results suggest that Ca^2+, Ca^2+-regulated ion channels, and CaM play an important role in dark-induced betacyanin accumulation in the shoots of the C3 halophyte S. salsa.
基金Supported by the Provincial Industrialization Application Project of China High-Resolution Earth Observation System (CHEOS) of State Administration of Science,Technology and Industry for National Defense,PRC (70-Y40G09-9001-18/20)Provincial Key Research and Development Project of Department of Science and Technology of Liaoning Province (2018108004)+1 种基金Climate Change Project of China Meteorological Administration (CCSF201910)China Meteorological Administration Construction Project in 2019 (Construction and Demonstration of Wetland Ecological Remote Sensing Application Capacity in Liaoning Province)。
文摘Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are therefore of great importance. We used medium-and high-resolution satellite data, meteorological station data, and site measurement data to analyze changes in the area and spatial distribution of Phragmites australis and Suaeda salsa in the Liaohe Delta Wetland from 1998 to 2017, as well as their growth response to the climate change. The results showed that during 1998–2017, the areas of both P. australis and S. salsa wetlands alternated through periods of decreasing,increasing, and then decreasing trends. The annual change in the area and spatial distribution range of S. salsa fluctuated more than that of P. australis. The annual variation of normalized difference vegetation index(NDVI) in P. australis wetland showed an upward trend from 1998 to 2017. The area of P. australis cover that was improved, unchanged, and decreased accounted for 81.8%, 12.3%, and 5.9%, respectively, of the total area;evaporation and wind speed were the main meteorological factors affecting the NDVI;and contribution rates of the climate change and human activities to the NDVI were 73.2% and 26.8%, respectively. The area with vegetation cover being mainly S.salsa that was improved, unchanged, and decreased accounted for 63.3%, 18.3%, and 18.4%, respectively, of the total area;and no meteorological factors significantly affected the NDVI of S. salsa in the region. The interaction between vegetation growth and meteorological factors may help to explain the increasing trend in vegetation cover.The improvement in wetland vegetation also led to carbon sequestration and an increase in sequestration capacity.
基金This study was supported by the Forestry Industry Research Special Funds for Public Welfare Project(201404305).
文摘Aims Pigment composition is an important functional trait that can be affected by environmental factors.the objective of this study was to investigate the effect of soil salinity on pigment composition in Suaeda salsa by comparing chlorophyll and betacyanin content in the Liaohe estuary wetland,a typical coastal wetland in northeast China.Methods We investigated the plant biomass,percentage of red leaves and pigment content(chlorophyll a,chlorophyll b and betacyanins)in S.salsa in intertidal and supratidal zones of the upper,middle and lower reaches of the Liaohe estuary wetlands.the Na^(+)content of both the soil and plant was also measured.Full analysis of variance and multivariate analysis were used to compare differences in pig-ment content and Na^(+)content between the supratidal and intertidal zones.Important Findings Pigment composition was significantly affected by soil salinity.With increasing soil salinity,the percentage of red leaves was higher in the intertidal zone than in the supratidal zone.In all three reaches,plants had lower chlorophyll a content and higher betacyanin con-tent in the intertidal zone than in the supratidal zone.Compared to chlorophyll a,chlorophyll b was less sensitive to soil salinity.there were no differences in chlorophyll b content between the intertidal and supratidal zones in the upper and lower reaches.Furthermore,pigment composition was associated with both the plant tissue and soil Na^(+)content.Compared to the supratidal zone,the intertidal zone had a higher Na^(+)content in plants.there was a negative rela-tionship between plant chlorophyll content and soil Na^(+)content,but a positive relationship between betacyanin content and soil Na^(+)content.Overall,the results indicated that there might be a trade-off between leaf chlorophyll and betacyanin content in S.salsa to main-tain its growth and survival in high salinity environments.
基金support provided by the National Natural Science Foundation of China(Grant No.U1503302,U1603241)the Tianshan Talent Project(Phase III)of the Xinjiang Uygur Autonomous Region and the Local People’s Government of the Xinjiang Uygur Autonomous Region in China sent abroad to study abroad as a complete set of projects(Grant No.L06).
文摘Xinjiang is the province with the largest saline-alkali land in China.The growth of halophytes will be stressed when their salt content reaches the threshold.In this study,the pot experiments were conducted and Suaeda salsa,a typical halophyte,was selected as the object to explore the relationship between growth characteristics and salt content under different soil salinity gradients.Salinity gradients were set according to the maximum soil salinity in the current years of Ebinur Lake Wetland National Nature Reserve(ELWNNR).They were classified using the following threshold values:≤2 g/kg(Control Group),10 g/kg,20 g/kg,30 g/kg,and 40 g/kg.The original spectrum,trilateral position and growth characteristics were used as indexes for analysis.With the increase of soil salt content,the red edge shift occurs first,followed by the blue edge shift.The position of yellow edge,green peak and blue edge were not sensitive to the change of soil salinity.This indicates that the red edge is the best indicator for evaluating plant growth.Compared with the Control Group,when the salt content is less than 10 g/kg,the growth status of plant seems not significantly affected.However,plant growth begins to be stressed when the salt content increases to 20 g/kg,which is a turning point for plant health.The increase of soil salt content can inhibit chlorophyll synthesis and plant growth.Plants begin to die when the salt content reaches 40 g/kg.Therefore,40 g/kg could be regarded as the critical point of salt content which inhibits plant growth.The study also shows that the relationship between plant-height change rate and soil salt content is the most significant,indicating that the plant-height change rate is significantly impacted by soil salt content.
基金This work was funded by the National Key R&D Program of China(2019YFC1407700).
文摘Suaeda salsa is an annual euhalophyte in estuarine wetlands.Soil properties of wetlands have an important influence on S.salsa growth.Therefore,the soil ecological thresholds is valuable for the restoration of degraded S.salsa wetlands.The objectives of this present study were to analyze the soil physicochemical properties and evaluate the soil ecological thresholds in the typical degraded areas for S.salsa growth.Soil text components became coarser with increased sand contents and less clay contents,as the higher degree of wetland degradation.Meanwhile,the salt contents in different soil depths gradually increased with the increased degree of degradation of wetlands.Evident changes in soil water content,organic matter content,and cations concentrations were not observed,while the concentrations of these factors were higher in the soil layer of 0-10 cm than those in the 20-30 cm.The soil pH in the 0-10 cm soil layer was lower than that in the 20-30 cm.The content of the three available nutrients did not change evidently with the increasing degree of degradation.The optimum thresholds of soil salinity and water content were 7.073-16.613 g/kg and 31.8-63.2%,respectively.