条锈菌侵染对小麦光合作用和蒸腾作用的影响

以小麦秀锈菌条中29号小种（CY－29）衣发接种感病品种辉县红和铭贤169，采用LI－6200型光合系统仪对小麦发病旗叶的光合作用和蒸腾作用进行监测。结果表明，不同严重度小麦病叶光合作用和蒸腾作用的日变化明显不同。轻度病叶（严重度为5％）光合作用和蒸腾作用的日变化与健叶相似，水分利用效率轻微下降。轻度病叶仍可有效控制水分的蒸腾散失，光合作用主要受气孔因素控制。中度病叶（严重度为40％0和重度病叶（严重度为80％）光合作用和蒸腾作用的日变化与健叶明显不同，病叶蒸腾作用在午前已大幅升高，并在此后一直保持很高的蒸腾水平，组织相对含水量大幅下降，光合作用和水分利用效率显著降低。中度和重度病叶完全丧失了控制水分散失的能力，光合作用主要受非气孔因素限制。中度和重度病叶光合作用的大幅降低不仅与叶绿素含量的明确下降有关，而且与叶绿素光合活性的下降有着密切的关系。

Effect of Stripe Rust Infection on Photosynthesis and Transpiration of Wheat

Huixianhong and Mingxian 169, susceptible to stripe rust ( Puccinia striformis West), were inoculated with CY 29 (virulent) in field. Photosynthesis and transpiration of diseased flag leaves were measured with LI 6200 Photosynthetic System. Diurnal changes in photosynthesis and transpiration of diseased wheat leaves with various severity were significantly different. Leaves with low severity(5%) were similar to healthy leaves in diurnal changes of photosynthesis and transpiration. Slight decreases in WUE (water utilization efficiency) were observed. Water losses through transpiration of the leaves with low severity were, still, under control and their photosynthesis was controlled by stomatal factors. Diurnal changes in photosynthesis and transpiration of leaves with medium severity (40%) or high severity (80%) were different greatly from the healthy leaves. Great increases in transpiration were found before noon and were kept in the whole afternoon, companied with much lower RWC (relative water content). Significant decreases in photosynthesis and WUE occurred. Flag leaves with medium and high severity had lost the ability to control water losses and their photosynthesis was controlled by non-stomatal factors. The significant decreases in photosynthesis of leaves with medium and high severity were related with the decreases in, not only chlorophyll content, but also photosynthetic activities of chlorophyll in the leaves.