The effects of changing salinity and nitrogen limitation on dimethylsulfoniopropionate(DMSP) and dimethylsulfide(DMS) concentrations were investigated in batch cultures of coastal diatom Skeletonema costatum,an ecolog...The effects of changing salinity and nitrogen limitation on dimethylsulfoniopropionate(DMSP) and dimethylsulfide(DMS) concentrations were investigated in batch cultures of coastal diatom Skeletonema costatum,an ecologically important species.Changes in salinity from 20-32 caused no measurable variation in cell growth or culture yield,but increased intracellular DMSP per cell by 30%.Nitrogen limitation caused up to a two-fold increase in total DMSP per cell and up to a three-fold increase in DMS per cell.These changes in DMSP and DMS per cell in the Skeletonema costatum cultures with nitrogen limitation and changing salinity were primarily attributed to the physiological functions of DMSP as an osmolyte and an antioxidant.The data obtained in this study indicated that nitrogen limitation and salinity may play an important role in climate feedback mechanisms involving biologically derived DMS.展开更多
The effects of CO2 enrichment on the growth and glueosinolate （GS） concentrations in the bolting stem of Chinese kale （Brassica alboglabra L.） treated with three nitrogen （N） concentrations （5, 10, and 20 mmol/...The effects of CO2 enrichment on the growth and glueosinolate （GS） concentrations in the bolting stem of Chinese kale （Brassica alboglabra L.） treated with three nitrogen （N） concentrations （5, 10, and 20 mmol/L） were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO2 concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO2 concentration, N concentration, and CO2×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those ofindolyl GSs were not affected, by elevated atmospheric CO2. However, at 20 mmol N/L, elevated CO2 had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon （C） content increased, whereas the N and sulfur （S） contents decreased under elevated CO2 concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO2 concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO2 condition.展开更多
基金Supported by the National Natural Science Foundation of China(Nos. 41030858 and 40525017)the Changjiang Scholars Program,Ministry of Education of China,the Science and Technology Key Project of Shandong Province (No. 2006GG2205024)the Taishan Scholars Program of Shandong Province
文摘The effects of changing salinity and nitrogen limitation on dimethylsulfoniopropionate(DMSP) and dimethylsulfide(DMS) concentrations were investigated in batch cultures of coastal diatom Skeletonema costatum,an ecologically important species.Changes in salinity from 20-32 caused no measurable variation in cell growth or culture yield,but increased intracellular DMSP per cell by 30%.Nitrogen limitation caused up to a two-fold increase in total DMSP per cell and up to a three-fold increase in DMS per cell.These changes in DMSP and DMS per cell in the Skeletonema costatum cultures with nitrogen limitation and changing salinity were primarily attributed to the physiological functions of DMSP as an osmolyte and an antioxidant.The data obtained in this study indicated that nitrogen limitation and salinity may play an important role in climate feedback mechanisms involving biologically derived DMS.
基金Project (No. 2007CB109305) supported by the National Basic Research Program (973) of China
文摘The effects of CO2 enrichment on the growth and glueosinolate （GS） concentrations in the bolting stem of Chinese kale （Brassica alboglabra L.） treated with three nitrogen （N） concentrations （5, 10, and 20 mmol/L） were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO2 concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO2 concentration, N concentration, and CO2×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those ofindolyl GSs were not affected, by elevated atmospheric CO2. However, at 20 mmol N/L, elevated CO2 had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon （C） content increased, whereas the N and sulfur （S） contents decreased under elevated CO2 concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO2 concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO2 condition.
