Allelopathic effects of persimmon (Diospyros kaki) leaves extracts on germination, seedling growth and enzymatic activities of receptor plants

摘要

We studied the mechanism of allelopathic effects of fresh persimmon (Diospyros kaki) leaves extract on: (i). seed germination, seedling growth and chlorophyll content of seedlings of receptor plant and (ii). analysed the activity of superoxidedismutase (SOD), peroxidase (POD), catalase (CAT) and root activity of receptor plants and content of malondialdehyde (MDA). The aqueous extracts of persimmon leaves had variable allelopathic effects on the receptor plants. All aqueous extracts significantly inhibited the lettuce and cabbage than control, but only high concentrations (50 mg and 100 mg) were inhibitory to mung bean, millet, rapeseed and corn. The extracts at 100 mg concentration were most inhibitory to lettuce and cabbage than other receptor plants. The growth and development of plants were significantly affected and the roots activity decreased with the increasing extracts concentration. The effects of extracts from persimmon leaves on activities of CAT, SOD, POD and the content of MDA of receptor plants were determined during the lettuce and cabbage seedling growth. The extracts had significant effects on the activities of CAT, SOD and POD in receptor plants, which in vivo first increased and then decreased. Of all the enzymes assayed (SOD, POD, CAT), the SOD and the POD activity cooperated to remove the reactive oxygen radicals. The allelopathy affected the activity of protective-enzymes of receptor plants and broke the structure and function of membrane. So the balance of activate oxygen metabolism was broken, the cell membrane was destroyed and the content of MDA increased.