遮荫处理对温室四种蔬菜生长及光合作用日变化的影响

Effect of shading on growth and diurnal photosynthetic changes of four vegetables in glasshouse

研究了温室中不同遮荫处理(温室自然光、一层遮阳网遮荫、二层遮阳网遮荫)对黄瓜、辣椒、番茄、茄子生长及光合作用日变化的影响。结果表明,两种遮荫均显著降低了四种蔬菜干物质的积累量,并且以二层遮荫处理条件下减少的最多。在温室自然光条件下,黄瓜、辣椒、番茄在9:00均出现了较为明显的光合作用下降的现象,其全天的净光合速率以一层遮荫处理的最大,温室自然光处理居中,二层遮荫处理最小,而茄子的净光合速率表现为温室自然光>一层遮荫处理>二层遮荫处理;四种蔬菜的胞间CO2浓度均为二层遮荫处理>一层遮阴处理>温室自然光。因此气孔限制可能是导致蔬菜在温室自然光条件下出现光合作用降低的主要原因,而整个植株叶肉细胞利用CO2能力降低的非气孔因素,可能是二层遮荫处理后蔬菜光合作用较低的主要原因,由此看出茄子对强光、高温的抗性较强。

Effect of different treatments of shading （glasshouse natural light,shading with one-layer shade net and two-layer shade net） on growth and the diurnal changes of photosynthesis in cucumber,pepper,tomato and eggplant was studied in glasshouse. The results indicated that dry matter accumulations of the four vegetables were greatly decreased by shading,and reduced most when shaded with two-layer shade net. Photosynthesis of cucumber,pepper and tomato was depressed at 9：00 under glasshouse natural light treatment. Moreover,the average whole-day photosynthetic rate was highest under one-layer shading treatment,the treatment with glasshouse natural light took the second place,and the photosynthetic rate was least when treated with two-layer shading. However,the photosynthetic rate of eggplant was glasshouse light treatment〉one-layer shading treatment〉two-layer shading treatment. The intercellular CO2 concentration of four vegetables with different treatments was two-layer shading treatment〉one-layer shading treatment〉glasshouse natural light treatment. Thus,stomatal limitation might be one of the factors leading to the photosynthesis depression in glasshouse natural light,meanwhile,non stomatal factor causing the lower ability of the whole plant leaf cell in utilizing CO2 was the main cause of the lower photosynthesis of two-layer shading treatment. Therefore,eggplant showed higher resistance to high light and high temperature stress.