水分胁迫对小麦叶片光合作用的影响及其与抗旱性的关系

在水分胁迫初期,两个小麦品种叶片光合速率,气孔导度和细胞间隙CO_2浓度降低,气孔限制值增加,光合速率的降低主要是气孔因素的限制。中度到严重水分胁迫使叶片光合速率、气孔导度和气孔限制值降低,细胞间隙CO_2浓度明显增加,且叶圆片放氧能力,叶绿体Hill反应、叶绿素荧光强度和表观量子产额降低,此时光合速率的降低主要是叶肉细胞光合活性的下降引起的。抗旱性弱的郑引一号叶肉细胞光合活性比抗旱性强的丰抗13更容易受到水分胁迫的影响。

EFFECTS OF WATER STRESS ON PHOTOSYNTHESIS OF WHEAT LEAVES AND THEIR RELATION TO DROUGHT RESISTANCE

Two cultivars of wheat(Drought resistant Feng kang No. 13 and Drought sensitive Zheng yin No. 1) seedings were used to determine the effect of water stress on photosynthesis. The results are as folloas: under mild water stress, net photosynthetic rate (Pn), stomatal couductance (Gs) and intercellutar CO_2 concentration (Ci) deoreased, but stomatal limiation (Ls) inc eased, which shows the decrease in Pn is mainly due to stomatal factors, However, under medium and serious warer stress,Pn,Gs,Ls, O_2-evolution rate of leaf discs, Hill reaction, chlorophyll fluorescence, and apparent quautum yield, but Ci increased. These results suggest that the decline of Pn is due mainly to non-stomatal factors. When subjected to water stress, the shift from stomatal factor to non-stomatal factor oceurred eariler in Zheng yin No. 1 than Feng kang No.13.