【摘要】 以盆栽5年生云锦杜鹃苗木为材料,分对照、轻度胁迫、中度胁迫、重度胁迫4组,研究了土壤水分胁迫对云锦杜鹃叶片光合特性日变化的影响。结果表明:随着水分胁迫的加重,云锦杜鹃的光合日变化曲线由典型的双峰型逐渐转变为峰值很小的单峰型,峰值的降低在轻度水分胁迫下由气孔限制引起,而在中度和重度水分胁迫下则由非气孔限制引起。轻度、中度和重度水分胁迫对云锦杜鹃光合特性日变化的影响差异显著。经逐步多元回归得到了净光合速率日变化的回归方程。更多还原

【Abstract】 5-year-old potted Rhododendron fortunei seedlings were used as experiment materials to simulate different soil water statuses.Twelve pots of seedlings showing similar growth were divided into 4 groups and treated with different levels of water stress by controlled irrigation: no stress(control),mild stress,moderate stress,severe stress.The pots were protected from exposure to rain.The results showed as follows.Water stress reduced the net photosynthesis rate(Pn).With increases in water stress,the daily progress pattern of Pn shifted from a typical double-peaked curve gradually to a single-peaked one,exhibiting significant depression of photosynthesis.According to the criteria suggested by Farquhar and Sharkey,the peak value depression of photosynthesis under mild drought conditions may be attributed to stomatal limitation,while that may be attributed to non-stomatal limitation under moderate stress and severe stress.The photosynthetic parameters of daily progress exhibiting significant difference under water stress.The most excellent equations of Pn of daily progress to environment factors were attained by the method of stepwise multi-regression.更多还原