Studies On Effect And Varietal Difference Of Allelopathic Potential Of White Clover And Tall Fescue

Allelopathy has been noticed by scientists all over the world in recent years, and it is an important factor in the development of ecology agriculture. With the adjustment of agriculture structure, forage crops play a vital role in agriculture production. It is needed to understand the allelopathic effect of forage crops for scientific arrangement in forage plant system and improving crop production efficiency.White clover (Trifolium repens) and tall fescue (Festuca anmdinacea) are widely planted because of their high yield and excellent quality. In recent years, the planting area of white clover and tall fescue has rapidly enlarged in farming zone with the development of animal husbandry. In order to discuss the allelopathic potential and its mechanism, the effects of water extracts of white clover and tall fescue on seed germination and seedling growth of radish (Raphanus sativus), greencovery(Brassica chinensis ) and Italian ryegrass (Lolium multiflorum) were studied. The mechanism of allelopathy of white clover and tall fescue was discussed by means of tissue slicing, enzyme mensurating and ailelochemicals analysis, and the difference of allelopathic potential among species and varieties was analyzed.The result indicated that extracts from all varieties significantly inhibited seed germination and seedling growth of the receptors. Allelopathic effects of white clover and tall fescue on the receptors were obviously different among species and varieties. Each receptor and each seedling organ of receptors showed specific response to ailelochemicals, and they were inhibited incoordinately.A preliminary analysis of ailelochemicals showed there were plenty of o-hydroxybenzene and m-hydroxybenzene in white clover and tall fescue. Cell growth of receptors was significantly inhibited by ailelochemicals. Mircostructurc of all organs of the receptors showed the cell array of seedlings became compact and the cell size became small after seedlings were treated with white clover and tall fescue extracts.The avtivity of SOD decreased and MDA content increased after treatment.This suggested that funtion of cell membrane was damaged by allelochemicals.The allelopathic effect of white clover and tall fescue was identical, but the allelopathic potential of white clover was stronger than that of tall fescue. The allelopathic potential of a cultivation Haifa was strongest among four varieties of white clover, and the allelopathic potential of Babian was also strongest among three varieties of tall fescue. Allelopathic potential of white clover and tall fescue changed significantly during different growing stages, and it displayed the strongest allelopathic potential in peak anthesis.White clover and tall fescue inhibited seed germination and seedling growth of radish, greencovery and Italian ryegrass because of their allelopathy. Therefore, the following crops should be arranged scientificly according their traits in production.