Studies on wetting injury of crop plant by rainfall.

1.研究了降雨后植物叶片的萎蔫和伤害。叶片结构增加，蒸腾作用大大增加。蒸腾作用的增加破坏了根系吸收和叶片损失之间的水分平衡，叶片水分亏缺，导致叶片萎蔫。降雨对菜豆第1、2叶造成伤害。暴露于降雨1-2天仅造成轻微伤害，但暴露3天或更长时间则有显著影响。叶片组织坏死后出现折边叶、坏死斑叶、心形叶、皱叶等多种症状.叶片的萎蔫和伤害程度可能与叶片的拒水性、与水的接触角、叶片表面蜡质和叶片含糖量的变化有关.测定了冈山仓敷和香川三木的雨水pH值和EC值。1988-1989年冈山和香川的年平均pH值分别为4.3和4.6。

1. Wilting and injury of plant leaves were examined after rainfall. The structure in leaf is increased, so that transpiration is increased greatly. The increase of transpiration destroyed the water balance between uptake by root and loss from leaf, and a water deficit occurred in leaf, resulting in the wilting of the leaves. Exposure to rainfall caused injury of the 1st and 2nd foliage leaves of kidney bean. Exposure to rainfall for 1-2 days caused only slight injury, but the exposure for 3 days or more had a marked effect. Various symptoms, such as edge break leaf, necrotic spot leaf, cordate leaf and rugose leaf, appeared as a result of the necrosis of leaf tissue.2. Degree of the wilting and injury may be attributed to differences in water- repellency, contact angle of water, superficial wax on leaves and change of sugar content in leaves.3. pH and EC of rain water at Kurashiki, Okayama and Miki, Kagawa were measured. Annual average pH values in 1988-1989 were 4.3 at Okayama and 4.6 at Kagawa.