Study On The Allelopathy And The Mechanism Of Walnut Seedcases

The phenomenon-plants or microorganism has a direct or indirect,beneficial or bad affect on other plants or microorganism through releasing some special chemica(lallelochemical)into circumstance is called allelopathy.Allejopathy is a very common and important ecological mechanism existed innature. The deep research on plant allelopathy has an important meaning on knowing the plant community and succession, logical application of agricultural cultivation system, exploitation of weeds-control by biology and new style pesticide.Walnut (Juglans regia L.) is a widespread tree in walnut genus (Juglans) of walnut family (Juglamd aceas). It is planted originally for a long history in China. The output of walnut green seedcase is 350 thousands ton. For this resource was fully utilized, the economic benefit of walnut production was enhanced, this article studied the allelopathic effects of extract of walnut green seedcase with different solvents. The results indicated these:(1)Secondary material of walnut green seedcase contains bioactivity inhibiting Composition,By extracting walnut green seedcase with water and 95%ethonal, the extracts all have certain inhibiting effect, and as concentration of extract increase, inhibiting effect strengthen.(2)Ethanol extract of walnut green seedcase was extracted in turn by petroleum ether, ethyl acetate and n-butyl alcohol.(3)The inhibition effect on crop of water extract was close to ethanol extract from walnut green seedcase. But the extraction rate of ethanol extract was higher than water extract.(4)After extracted by ether,the ethanol extract 2Fr5 separated by silica gel column-chromatography has high inhibiting rate over 70% on root and bud of wheat and cole, so 2Fr5 is main active allelopathic compound for allelopathy.(5)The allelopathic substance of walnut green seedcase has selectivity to inhibiting young seedling, each extract has stronger inhibition on young root than on young shoot.(6)The allelopathic substance of walnut green seedcase has selectivity to inhibiting the site of young seedling, each extract has stronger inhibition on young root than on young shoot. (7)The compound A was obtained after recrystallization form 2Fr5. The compound A had some influences on physiological activities and enzyme activities of wheat seedlings on growth process. The activities of POD and the content of MDA were increased. The activities of SOD and CAT and the content of protein were decreased. The compound A had greater influences on roots than buds.