ALLELOPATHIC EFFECTS OF DIFFERENT WEED EXTRACTS ON SEED GERMINATION AND SEEDLING GROWTH OF WHEAT

The present study identified wheat varieties with strong grass resistance, clarified the physiological mechanism of their anti-grassing effect, and provided a scientific basis for the application of grass-resistant wheat varieties for producing high and stable yield of wheat. Ten wheat varieties commonly used in production were selected to study the effects of Descurainia sophia, Galium tricorne, Wild oat, and sativa extracts on seed germination and seedling growth. Results showed that the Descurainia sophia, Galium tricorne, Wild oat, and Vicia sativa extracts exhibited allelopathic inhibition on wheat seed germination and seedling growth. The allelopathic indices of wheat seed germination rate, seedling height, and root length were -0.12 to -0.19, -0.70 to -0.87, and -0.70 to -0.91, respectively. The weed extract had certain differences in allelopathic inhibition on wheat. The Wild oat extract had the strongest inhibitory effect on seed germination, whereas the Descurainia sophia extract showed the weakest inhibitory effect. The Vicia sativa extract had the strongest inhibitory effect on seedling growth, whereas the Galium tricorne extract showed the weakest inhibitory effect. According to the absolute value of allelopathic index, the effects of the four kinds of weed extracts on seedling growth index were systematically clustered. Results showed that the allelopathic inhibition rate of weed extracts on Wanmai 19 was weak, and the weed resistance was strong. The weed extracts had an allelopathic effect on the root activity and activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in the leaves and could promote the content of malondialdehyde (MDA) in the leaves. However, they had minimal allelopathic effect on Wanmai 19. The seedling height and root length of wheat seedlings were significantly correlated with root activity, activities of SOD, POD, and CAT in the leaves and MDA content. Thus, the effect of allelochemicals on the cell membrane in weed extracts could be the cause of inhibited wheat growth.