Doubled CO2 could improve the drought tolerance better in sensitive cultivars than in tolerant cultivars in spring wheat

摘要

Effects of doubled CO2 concentration on drought stress tolerance were investigated in two spring wheat cultivars (Triticum aestivum L. Longchun 292 and Longchun 8139). Doubled CO2 decreased protein and chlorophyll in the two cultivars, but decreased total SOD activity mainly by decreasing FeSOD and decreased GSH/GSSG and AS/DHA ratios by converting more GSH and AS to GSSG and DHA only in 8139. After stress, as to every parameter, the curve changes were similar both in 292 and in 8139 regardless of ambient or doubled CO2 and could be divided into two stages. Under ambient CO2, the first stages were observed from days 0 to 6 in 292 and from days 0 to 5 in 8139. This result showed that 292 were more tolerant to drought stress than 8139 under ambient CO2. The decreases in protein, chlorophyll, activities of antioxidant enzymes and GSH/GSSG and AS/DHA ratios and the increases in H2O2 contents, TBARS contents and relative leakage ration induced by drought stress were delayed by doubled CO2 and the initial of the second stages was delayed 3 days in 8139 and 2 days in 292, then the first stages were observed from days 0 to 8, both in 292 and 8139. The results indicated that doubled CO2 could enhance antioxidant systems to increase the tolerance to drought stress and this effect was stronger in the cultivars, which are more sensitive to drought under ambient CO2. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved. [References: 43]