Brassica chinensis L. were foliarly applied with glycinebetaine (GB), as this species is unable to synthesis GB and sensitive to osmotic stress such as salt. The exogenous GB was easily absorbed and transported by t...Brassica chinensis L. were foliarly applied with glycinebetaine (GB), as this species is unable to synthesis GB and sensitive to osmotic stress such as salt. The exogenous GB was easily absorbed and transported by the leaf of B. chinensis . Its application (0-20 mmol/L) enhanced the plant tolerance to salt stress. The treatment of 15 mmol/L GB significantly decreased the Na + accumulation in leaf and root under NaCl stress. This difference in accumulating Na + and K + is caused by higher selectivity of root absorption. Furthermore, GB increased H +_ATPase activity of root plasma membrane evidently. This result strongly suggested that in root the decreased Na + accumulation was caused by the GB accumulation that enhanced the extrusion of Na + from the cell in some way through plasma membrane transporter, e.g. Na +/H + antiport driven by H +_ATPase. The GB application was also found to stabilize the plasma membrane, to decrease the loss of chlorophyll, and to stimulate the osmosis induced proline response under salt stress.展开更多
Glycinebetaine （Glybet） accumulation, photosynthetic efficiency and growth performance in indica rice cultivated under salt stress and extreme pH stress were investigated. Betaine aldehyde dehydrogenase （BADH） act...Glycinebetaine （Glybet） accumulation, photosynthetic efficiency and growth performance in indica rice cultivated under salt stress and extreme pH stress were investigated. Betaine aldehyde dehydrogenase （BADH） activity and Glybet accumulation in the seedlings of salt-tolerant and salt-sensitive rice varieties grown under saline and acidic conditions peaked after treatment for 72 h and 96 h, respectively, and were higher than those grown under neutral pH and alkaline salt stress. A positive correlation was found between BADH activity and Glybet content in both salt-tolerant （P=0.71） and salt-sensitive （P=0.86） genotypes. The chlorophyll a, chlorophyll b, total chlorophyll and total carotenoids contents in the stressed seedlings significantly decreased under both acidic and alkaline stresses, especially in the salt-sensitive genotype. Similarly, the maximum quantum yield of PSII （Fv/Fm）, photon yield of PSII （ФPSII）, non-photochemical quenching （NPQ） and net photosynthetic rate （Pn） in the stressed seedlings were inhibited, leading to overall growth reduction. The positive correlations between chlorophyll a content and Fv/Fm, total chlorophyll content and ФPSII, and Pn as well as Pn and leaf area in both salt-tolerant and salt-sensitive genotypes were found. Saline acidic and saline alkaline soils may play a key role affecting vegetative growth prior to the reproductive stage in rice plants.展开更多
文摘Brassica chinensis L. were foliarly applied with glycinebetaine (GB), as this species is unable to synthesis GB and sensitive to osmotic stress such as salt. The exogenous GB was easily absorbed and transported by the leaf of B. chinensis . Its application (0-20 mmol/L) enhanced the plant tolerance to salt stress. The treatment of 15 mmol/L GB significantly decreased the Na + accumulation in leaf and root under NaCl stress. This difference in accumulating Na + and K + is caused by higher selectivity of root absorption. Furthermore, GB increased H +_ATPase activity of root plasma membrane evidently. This result strongly suggested that in root the decreased Na + accumulation was caused by the GB accumulation that enhanced the extrusion of Na + from the cell in some way through plasma membrane transporter, e.g. Na +/H + antiport driven by H +_ATPase. The GB application was also found to stabilize the plasma membrane, to decrease the loss of chlorophyll, and to stimulate the osmosis induced proline response under salt stress.
基金supported by the National Center for Genetic Engineering and Biotechnology (BIOTEC) (Grant No. BT-B-06-RG-14-4502)partly funded by the International Atomic Energy Agency (IAEA) (Contract No. 12998/R0)
文摘Glycinebetaine （Glybet） accumulation, photosynthetic efficiency and growth performance in indica rice cultivated under salt stress and extreme pH stress were investigated. Betaine aldehyde dehydrogenase （BADH） activity and Glybet accumulation in the seedlings of salt-tolerant and salt-sensitive rice varieties grown under saline and acidic conditions peaked after treatment for 72 h and 96 h, respectively, and were higher than those grown under neutral pH and alkaline salt stress. A positive correlation was found between BADH activity and Glybet content in both salt-tolerant （P=0.71） and salt-sensitive （P=0.86） genotypes. The chlorophyll a, chlorophyll b, total chlorophyll and total carotenoids contents in the stressed seedlings significantly decreased under both acidic and alkaline stresses, especially in the salt-sensitive genotype. Similarly, the maximum quantum yield of PSII （Fv/Fm）, photon yield of PSII （ФPSII）, non-photochemical quenching （NPQ） and net photosynthetic rate （Pn） in the stressed seedlings were inhibited, leading to overall growth reduction. The positive correlations between chlorophyll a content and Fv/Fm, total chlorophyll content and ФPSII, and Pn as well as Pn and leaf area in both salt-tolerant and salt-sensitive genotypes were found. Saline acidic and saline alkaline soils may play a key role affecting vegetative growth prior to the reproductive stage in rice plants.
