土壤水分对日光温室黄瓜生长发育及光合特性的影响

黄瓜是需水量大且对水分敏感的蔬菜作物之一，水分管理的好坏是实现日光温室黄瓜高产高效的关键。为此，本文研究了不同土壤水分条件对日光温室黄瓜形态指标及光合特性的影响，结果如下：① 保持80%~90%的土壤相对含水量(T3)，植株生长发育良好，根冠比适宜，生物量、单瓜重及产量高，畸形率低，均显著高于低水处理(T1: 60%~70%, T2: 70%~80%)，而与高水处理(T4: 90%~100%)差异不显著；低于此含水量(如T1、T2)，生长缓慢，植株矮小，瓜条畸形率高，单瓜重小，产量低；高于此含水量(如T4)，则植株徒长，水分利用效率低，同时也为病虫害发生提供了适宜的环境条件。② 从光合特性及其日变化来看，净光合速率、蒸腾速率、气孔导度及光能利用率均随土壤含水量的增加而增加，而叶片水分利用效率随土壤含水量的增加而呈降低趋势；T2、T3与T4的净光合速率、蒸腾速率、气孔导度及光能利用率日变化呈双峰曲线，第一峰出现在11：00时，第二峰出现在15：00时；而T1则呈单峰曲线，峰值出现在10：00时，比T2、T3、T4提前1小时，水分利用效率日变化呈先升后降的趋势。

The effect of soil moisture on growth & development and photosynthetic characteristics of Cucumis statirus L. in solar greenhouse

Cucumis statirus L. is one of the vegetables which are not only in great need of water, but also sensitive to it. So it is very important to manage irrigation for realizing high yield and great efficiency. Therefore, the morphological characters, physiological and photosynthetic characteristics under different soil moisture were studied in this paper. The results are shown below: ① Under 80%~90% relative soil moisture(T3), it was much better in growth& development and root/canopy ratio, higher in per cucumber weight and yield, lower in malformation rate than those under lower relative soil moisture(T1: 60%~70%, T2: 70%~80%) and the difference of which between T3 and T1 ,T2 were greatly significant, but there was no significant difference between T3 and T4(90%~100%). If relative soil moisture was kept lower(T1,T2), some bad results came accordingly, such as slower growth, lower height, higher malformation rate of cucumber, lighter per cucumber weight and lower yield than those of T3. Contrarily, higher relative soil moisture(T4) also brought many disadvantageous results, such as expansive growth, lower water use efficiency, tremendous waste of water and comfortable environment for disease and insect pests. ② From the view of photosynthetic characteristics and diurnal variation, Net photosynthetic rate, transpiration rate, stomatal conductance and light use efficiency grew increasing with the increase of soil moisture. However, water use efficiency took on opposite trend when soil moisture got higher. The net photosynthetic rate, transpiration rate, stomatal conductance and light use efficiency of T2,T3 and T4 presented a double-peak curve and the first peak appeared at 11:00 o’clock, the second one came forth at 15:00 o’clock. Nevertheless, diurnal variation of photosynthetic characteristics mentioned above of T1 took on a single-peak curve, and the peak emerged at 10:00 o’clock, one hour earlier than that of T2,T3 and T4. The diurnal variation of water use efficiency presented descending trend on the whole.