Photochemical Oxidants Injury in Rice Plants : I. Occurrence of Photochemical Oxidants Injury in Rice Plants at Kanto Area and its Symptoms

[摘要] The investigation reported here was conducted to elucidate the cause of the occurrence of Akagare like disease in rice plants. Recently this injury has been frequently observed in many rice cultivation areas in Kanto, Japan. The results obtained were as follows: 1. Rice plants were placed both in the filtered air chamber which removed the toxic agents from the polluted air and the unfiltered air chamber, plants on the unfiltered air chamber occurred small flecks of bronzing and chlorosis on leaf blade following period of air pollution. In contrast, plants receiving filtered air not only were free of any injury but were much more vigorous in growth. 2. By fumigation with ozone for one hour at 15 pphm, test plants developed injury very similar to Akagare like disease due to photochemical oxidants. 3. Photochemical oxidants injury in rice plants occurred most severely on the second leaf counted from the tip of the completely expanded leaf. Symptoms appeared mainly on the upper surface of the leaf blade and were observed microscopically at the mesophyll cells surrounded stomata. On the other hand in Akagare disease I, II and III it was found that the stomata were free from injury. It was also found by a scanning electron microscope as shown in photographs that in the badly oxidants damaged areas the guard cells degenerated and the stomata were pulled open by injury. From above observation, it was concluded that the injury was caused by the exposure of photochemical oxidants and it can be distinguished the photochemical oxidants injury from the Akagare disease in rice plants.

[学科分类] 农业科学（综合）