The ion levels in the epidermal bulliform cells of epidermis, mesophyll cells and cells of the vascular bundle sheath of four ecotypes of reed (Phragmites australis (Cav.) Trin. ex Steud.) were determined by means of ...The ion levels in the epidermal bulliform cells of epidermis, mesophyll cells and cells of the vascular bundle sheath of four ecotypes of reed (Phragmites australis (Cav.) Trin. ex Steud.) were determined by means of X_ray microanalysis. The results indicated that higher K +, Na +, Ca 2+ , Mg 2+ and Cl - were distributed in the vascular bundle sheath cells than in mesophyll cells and epidermal bulliform cells of the swamp ecotype. Higher Ca 2+ was found in the bulliform cells than in mesophyll cells and vascular bundle sheath cells, higher Mg 2+ in the mesophyll cells and higher K +, Na + and Cl - in the vascular bundle sheath cells of the dune ecotype. Higher Na + and Mg 2+ was determined in the mesophyll cells than in the bulliform cells and vascular bundle sheath cells, and higher K +, Ca 2+ and Cl - in the vascular bundle sheath cells of the light salt meadow ecotype. In the heavy salt meadow ecotype, higher Na + and Mg 2+ were accumulated in the bulliform cells than in mesophyll cells and vascular bundle sheath cells, but higher K +, Ca 2+ and Cl - in the mesophyll cells. Furthermore, the distributional conditions of the above five ions in leaf cells of the four ecotypes and their significance in the physiological adaptation of reed to habitat were discussed in detail.展开更多
The competitor,stress tolerator,and ruderal strategy(CSR)framework has been widely applied to explain ecological processes across species.However,its utility in revealing intra-specific trade-offs and genetic adaptati...The competitor,stress tolerator,and ruderal strategy(CSR)framework has been widely applied to explain ecological processes across species.However,its utility in revealing intra-specific trade-offs and genetic adaptation to climate remains unclear.In this study,we examined whether the CSR strategy estimated by leaf traits can identify adaptations to climate in the common reed Phragmites australis.For this purpose,we integrated functional trait data from field surveys and a three-year common garden experiment to compare CSR scores between two typical populations of P.australis from western and eastern China.We further assessed the associations of CSR scores with latitude,bioclimatic factors,and phylogeographical sources using a global dataset including two invaded lineages in the North America.We found that competitor scores were positively correlated with latitude,whereas stress tolerator scores were negatively correlated.Competitor scores were positively correlated with bioclimatic factors,even when controlling for phylogeny.All CSR scores displayed significant phylogenetic signals,with the invasive lineage in the higher latitudes(haplotype M)exhibiting higher stress tolerator scores than the native lineage.Differences in competitor and stress tolerator scores between western and eastern Chinese populations of P.australis were consistent across field and common garden experiments.Although intra-species variation in CSR strategy may be influenced by phylogenetic history,our finding that CSR strategy in P.australis populations is correlated with latitude suggests these plants have adapted to local climates along a latitudinal gradient.展开更多
Shallow lake eutrophication is a global environmental issue. This study investigated the effects of water level variation and nutrient loadings on the growth and nutrient accumulation of Phragmites australis （reed） ...Shallow lake eutrophication is a global environmental issue. This study investigated the effects of water level variation and nutrient loadings on the growth and nutrient accumulation of Phragmites australis （reed） by field samplings in Baiyangdian Lake, the largest shallow lake of northern China. The field samplings were conducted in two sites of different nutrient loadings during the whole growth period of reeds, and three types of zones with different water depths were chosen for each site, including the terrestrial zone with water level below the ground, the ecotone zone with the water level varying from belowground to aboveground, and the submerged zone with water level above the ground. The result showed that reed growth was more limited by water level variation than nutrient loadings. The average stem lengths and diameters in terrestrial zones were about 26.3%-27.5% and 7.2%-12.0% higher than those in submerged zones, respectively. Similarly, the terrestrial status increased the aboveground biomass of reeds by 36.6%-51.8% compared with the submerged status. Both the nutrient concentrations and storages in the aboveground reeds were mainly influenced by the nutrient loadings in surface water and sediment rather than the water level variation of the reed growth environment, and the nutrient storages reached their maxima in late August or early September. It was observed that the maximum nitrogen storage occurred in the terrestrial zone with higher nutrient loadings, with the value of 74.5 g/m2. This study suggested that water level variation and nutrient loadings should be considered when using reeds to control and remediate eutrophication of shallow lakes.展开更多
Two plant populations of Phragmites australis and Typha orientalis grown in gravel and sediment substrate were studied to assess their capabilities for purifying polluted water in Taihu Lake, China. The substrate disp...Two plant populations of Phragmites australis and Typha orientalis grown in gravel and sediment substrate were studied to assess their capabilities for purifying polluted water in Taihu Lake, China. The substrate displayed most significant effects on the suspended matter （P 〈 0.01）, with the reduction of 76%-87% and 52%--63% for P. australis, and 83%-86% and 45%-62% for T. orientalis in gravel substrate and sediment substrate, respectively. Both species and substrates significantly decreased the N and P concentrations of water body （P 〈 0.01）. P. australis showed higher total N and P concentrations in tissues than T. orientalis and had a greater potential to remove nutrients from the lake. Phosphate was easily to concentrate in the belowground tissues, while nitrate concentration was higher in leaf and stalk. Therefore, harvesting the aboveground tissues could take most of nitrate out of the sediment. The saturate photosynthetic rate （Asat） of P. australis was higher than that of T. orientalis when grown in sediment substrate. But instance water-use- efficiency （WUEi） （A/E） and intrinsic water use efficiency （A/gs） showed the maximum values of two species grown in river water. With significant difference in gs, however, intercellular CO2 concentration （Ci） had no obvious difference in two species which indicated that high Asat value of P. australis might result from the increased carboxylation capacity of the mesophyll, because of the central role of N in photosynthetic enzymes. Our findings suggest that the plants could absorb most of nitrogen in polluted water, while gravel displayed a high capacity for absorbing the suspended matters and phosphate salts. Therefore, biological and physiological pathways for pollutant removal should be integrated.展开更多
The field trial was established to investigate the effects of planting condition(soil water content,soil buried depth,rhizome length)and time on the survival rate and growth of Phragmites australis rhizomes.The result...The field trial was established to investigate the effects of planting condition(soil water content,soil buried depth,rhizome length)and time on the survival rate and growth of Phragmites australis rhizomes.The results indicated that survival rate and growth of Phragmites australis were affected by soil water content and rhizome length significantly,but not by soil buried depth.The survival rate of Phragmites australis in moist condition was higher than those in natural and flooding conditions.Rhizomes length did not affect survival rate,height and shoot number,but influenced biomass and buds number,which were higher with 15 cm length than those with 30 cm length.Based on the suitable soil water content(moisture)and rhizome length(15 cm),the survival rate of Phragmites australis was the highest when they were planted in May(91%)comparing to June and July.The number of shoots and buds were the highest in June,which had more suitable temperature and light for Phragmites australis to grow.Therefore,the optimizing transplanting condition of Phragmites australis was that rhizomes of 15 cm with some buds were planted in May with moisture(soil water content).展开更多
In order to investigate distributions of heavy metal pollution in Quanzhou Bay wetland, the total concentration and chemical partitioning of a number of heavy metals （Cu, Zn, Cd, Pb, Cr, Hg） in sediments of three sa...In order to investigate distributions of heavy metal pollution in Quanzhou Bay wetland, the total concentration and chemical partitioning of a number of heavy metals （Cu, Zn, Cd, Pb, Cr, Hg） in sediments of three sampling sites of Quanzhou Bay wetland and their availability to Suaeda australis were analyzed. The Geoaccumulation Index （Igeo） values reveal that the sediments of three sampling sites may all be considered as moderately contaminated for Pb and Zn, and all sediments might be strongly contaminated with cadmium. The partitioning analyses revealed the measured heavy metals in three sites are bound to the exchangeable fraction at lower concentrations. The measured metals in a considerable amount are bound to the reducible and oxidizable fractions, and a high proportion of the measured heavy metals were distributed in the residual fraction in the sediment samples. The concentrations of Cd in each chemical phase extracted from the sediments are above natural global background levels and should be further investigated because of its toxicity. Suaeda australis has different accumulation abilities for the measured heavy metals. For the root and stem, the bioaccumulation ability assessed by bioaccumulation factor （BAF） for the measured heavy metals follows the decreasing order as： Cu〉Cr〉 Zn〉Cd, Pb, Hg. In the leaf, stronger bioaccumulation ability for Hg is exhibited. The heavy metal concentrations in Suaeda australis roots have positive correlations with their available fractions, while the exchangeable fraction of Cu and Cd might have be more important to both mature plant roots and seedling roots uptake than other fractions; as for Cr, the oxidizable fraction might make a greater contribution to the plant root uptake; as for Zn, the reducible fraction might make so contribution ; and for Pb, the oxidizable fraction might make a significant contribution to the mature plant root uptake, however, the exchangeable fraction might have a significant contribution to the seedling root uptake.展开更多
Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using ...Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using static chamber-gas chromatography technique with monthly sampling. The results showed that the fluxes of H_2S and COS both had distinct seasonal and diurnal variations. The H_2S fluxes ranged from 0.09 μg/(m^2·h) to 7.65 μg/(m^2·h), and the COS fluxes ranged from –1.10 μg/(m^2·h) to 3.32 μg/(m^2·h). The mean fluxes of H_2S and COS from the P. australis coastal marsh were 2.28 μg/(m^2·h), and 1.05 μg/(m^2·h), respectively. The P. australis coastal marsh was the emission source of both H_2S and COS over the whole year. Fluxes of H_2S and COS were both higher in plant growing season than in the non-growing season. Temperature had a dramatic effect on the H_2S emission flux, while the correlations between COS flux and the environmental factors were not found during sampling periods. More in-depth and comprehensive research on other related factors, such as vegetation, sediment substrates, and tidal action is needed to discover and further understand the key factors and the release mechanism of sulfur gases.展开更多
文摘The ion levels in the epidermal bulliform cells of epidermis, mesophyll cells and cells of the vascular bundle sheath of four ecotypes of reed (Phragmites australis (Cav.) Trin. ex Steud.) were determined by means of X_ray microanalysis. The results indicated that higher K +, Na +, Ca 2+ , Mg 2+ and Cl - were distributed in the vascular bundle sheath cells than in mesophyll cells and epidermal bulliform cells of the swamp ecotype. Higher Ca 2+ was found in the bulliform cells than in mesophyll cells and vascular bundle sheath cells, higher Mg 2+ in the mesophyll cells and higher K +, Na + and Cl - in the vascular bundle sheath cells of the dune ecotype. Higher Na + and Mg 2+ was determined in the mesophyll cells than in the bulliform cells and vascular bundle sheath cells, and higher K +, Ca 2+ and Cl - in the vascular bundle sheath cells of the light salt meadow ecotype. In the heavy salt meadow ecotype, higher Na + and Mg 2+ were accumulated in the bulliform cells than in mesophyll cells and vascular bundle sheath cells, but higher K +, Ca 2+ and Cl - in the mesophyll cells. Furthermore, the distributional conditions of the above five ions in leaf cells of the four ecotypes and their significance in the physiological adaptation of reed to habitat were discussed in detail.
基金supported by the National Natural Science Foundation of China(No.32100304,32470388,U22A20558,32271588).
文摘The competitor,stress tolerator,and ruderal strategy(CSR)framework has been widely applied to explain ecological processes across species.However,its utility in revealing intra-specific trade-offs and genetic adaptation to climate remains unclear.In this study,we examined whether the CSR strategy estimated by leaf traits can identify adaptations to climate in the common reed Phragmites australis.For this purpose,we integrated functional trait data from field surveys and a three-year common garden experiment to compare CSR scores between two typical populations of P.australis from western and eastern China.We further assessed the associations of CSR scores with latitude,bioclimatic factors,and phylogeographical sources using a global dataset including two invaded lineages in the North America.We found that competitor scores were positively correlated with latitude,whereas stress tolerator scores were negatively correlated.Competitor scores were positively correlated with bioclimatic factors,even when controlling for phylogeny.All CSR scores displayed significant phylogenetic signals,with the invasive lineage in the higher latitudes(haplotype M)exhibiting higher stress tolerator scores than the native lineage.Differences in competitor and stress tolerator scores between western and eastern Chinese populations of P.australis were consistent across field and common garden experiments.Although intra-species variation in CSR strategy may be influenced by phylogenetic history,our finding that CSR strategy in P.australis populations is correlated with latitude suggests these plants have adapted to local climates along a latitudinal gradient.
基金supported by the Major State Basic Research Development Program (No.2010CB951104)the Program for New Century Excellent Talents in University (No. NCET-09-0233)the National Water Pollution Control and Treatment Project in China (No.2008ZX07209-009)
文摘Shallow lake eutrophication is a global environmental issue. This study investigated the effects of water level variation and nutrient loadings on the growth and nutrient accumulation of Phragmites australis （reed） by field samplings in Baiyangdian Lake, the largest shallow lake of northern China. The field samplings were conducted in two sites of different nutrient loadings during the whole growth period of reeds, and three types of zones with different water depths were chosen for each site, including the terrestrial zone with water level below the ground, the ecotone zone with the water level varying from belowground to aboveground, and the submerged zone with water level above the ground. The result showed that reed growth was more limited by water level variation than nutrient loadings. The average stem lengths and diameters in terrestrial zones were about 26.3%-27.5% and 7.2%-12.0% higher than those in submerged zones, respectively. Similarly, the terrestrial status increased the aboveground biomass of reeds by 36.6%-51.8% compared with the submerged status. Both the nutrient concentrations and storages in the aboveground reeds were mainly influenced by the nutrient loadings in surface water and sediment rather than the water level variation of the reed growth environment, and the nutrient storages reached their maxima in late August or early September. It was observed that the maximum nitrogen storage occurred in the terrestrial zone with higher nutrient loadings, with the value of 74.5 g/m2. This study suggested that water level variation and nutrient loadings should be considered when using reeds to control and remediate eutrophication of shallow lakes.
基金supported by the Control and Treatment of Water Pollution Implementation Scheme of the National Important Science and Technology Project(No. 2008ZX07526-002)the Hi-Tech Research and Development Program (863) of China (No. 2002AA601012-06)the National Basic Research Program (973) of China (No. 2002CB412409)
文摘Two plant populations of Phragmites australis and Typha orientalis grown in gravel and sediment substrate were studied to assess their capabilities for purifying polluted water in Taihu Lake, China. The substrate displayed most significant effects on the suspended matter （P 〈 0.01）, with the reduction of 76%-87% and 52%--63% for P. australis, and 83%-86% and 45%-62% for T. orientalis in gravel substrate and sediment substrate, respectively. Both species and substrates significantly decreased the N and P concentrations of water body （P 〈 0.01）. P. australis showed higher total N and P concentrations in tissues than T. orientalis and had a greater potential to remove nutrients from the lake. Phosphate was easily to concentrate in the belowground tissues, while nitrate concentration was higher in leaf and stalk. Therefore, harvesting the aboveground tissues could take most of nitrate out of the sediment. The saturate photosynthetic rate （Asat） of P. australis was higher than that of T. orientalis when grown in sediment substrate. But instance water-use- efficiency （WUEi） （A/E） and intrinsic water use efficiency （A/gs） showed the maximum values of two species grown in river water. With significant difference in gs, however, intercellular CO2 concentration （Ci） had no obvious difference in two species which indicated that high Asat value of P. australis might result from the increased carboxylation capacity of the mesophyll, because of the central role of N in photosynthetic enzymes. Our findings suggest that the plants could absorb most of nitrogen in polluted water, while gravel displayed a high capacity for absorbing the suspended matters and phosphate salts. Therefore, biological and physiological pathways for pollutant removal should be integrated.
基金Under the auspices of the National Natural Science Foundation of China(31100403)National Basic Research Program of China(No:2012CB956100)
文摘The field trial was established to investigate the effects of planting condition(soil water content,soil buried depth,rhizome length)and time on the survival rate and growth of Phragmites australis rhizomes.The results indicated that survival rate and growth of Phragmites australis were affected by soil water content and rhizome length significantly,but not by soil buried depth.The survival rate of Phragmites australis in moist condition was higher than those in natural and flooding conditions.Rhizomes length did not affect survival rate,height and shoot number,but influenced biomass and buds number,which were higher with 15 cm length than those with 30 cm length.Based on the suitable soil water content(moisture)and rhizome length(15 cm),the survival rate of Phragmites australis was the highest when they were planted in May(91%)comparing to June and July.The number of shoots and buds were the highest in June,which had more suitable temperature and light for Phragmites australis to grow.Therefore,the optimizing transplanting condition of Phragmites australis was that rhizomes of 15 cm with some buds were planted in May with moisture(soil water content).
文摘In order to investigate distributions of heavy metal pollution in Quanzhou Bay wetland, the total concentration and chemical partitioning of a number of heavy metals （Cu, Zn, Cd, Pb, Cr, Hg） in sediments of three sampling sites of Quanzhou Bay wetland and their availability to Suaeda australis were analyzed. The Geoaccumulation Index （Igeo） values reveal that the sediments of three sampling sites may all be considered as moderately contaminated for Pb and Zn, and all sediments might be strongly contaminated with cadmium. The partitioning analyses revealed the measured heavy metals in three sites are bound to the exchangeable fraction at lower concentrations. The measured metals in a considerable amount are bound to the reducible and oxidizable fractions, and a high proportion of the measured heavy metals were distributed in the residual fraction in the sediment samples. The concentrations of Cd in each chemical phase extracted from the sediments are above natural global background levels and should be further investigated because of its toxicity. Suaeda australis has different accumulation abilities for the measured heavy metals. For the root and stem, the bioaccumulation ability assessed by bioaccumulation factor （BAF） for the measured heavy metals follows the decreasing order as： Cu〉Cr〉 Zn〉Cd, Pb, Hg. In the leaf, stronger bioaccumulation ability for Hg is exhibited. The heavy metal concentrations in Suaeda australis roots have positive correlations with their available fractions, while the exchangeable fraction of Cu and Cd might have be more important to both mature plant roots and seedling roots uptake than other fractions; as for Cr, the oxidizable fraction might make a greater contribution to the plant root uptake; as for Zn, the reducible fraction might make so contribution ; and for Pb, the oxidizable fraction might make a significant contribution to the mature plant root uptake, however, the exchangeable fraction might have a significant contribution to the seedling root uptake.
基金National Nature Science Foundation of China(No.41103036)Natural Science Foundation of Shandong Province,China(No.BS2009HZ013)
文摘Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using static chamber-gas chromatography technique with monthly sampling. The results showed that the fluxes of H_2S and COS both had distinct seasonal and diurnal variations. The H_2S fluxes ranged from 0.09 μg/(m^2·h) to 7.65 μg/(m^2·h), and the COS fluxes ranged from –1.10 μg/(m^2·h) to 3.32 μg/(m^2·h). The mean fluxes of H_2S and COS from the P. australis coastal marsh were 2.28 μg/(m^2·h), and 1.05 μg/(m^2·h), respectively. The P. australis coastal marsh was the emission source of both H_2S and COS over the whole year. Fluxes of H_2S and COS were both higher in plant growing season than in the non-growing season. Temperature had a dramatic effect on the H_2S emission flux, while the correlations between COS flux and the environmental factors were not found during sampling periods. More in-depth and comprehensive research on other related factors, such as vegetation, sediment substrates, and tidal action is needed to discover and further understand the key factors and the release mechanism of sulfur gases.
