Preliminary Study On The Endogenesis Inhibitory Substance Of Walnut

Walnut (Juglans regia L.) is a widespread tree in walnut genus (Juglans) of walnut family (Juglamdaceas). It is a plant cultured originally for a long history in china. Walnut is one of the four dry fruits in the world for its rich nutrition, distinct flavor and multiplex using. The walnut seeds could germinate with the pretreatment before planting. The relative reports shows that lots of plants'seeds such as Korean pine, Yew, Balloon-flower root contain inhibitory substances, which have a certain inhibiting effect on seed germination. However, there is nothing about whether walnut seed contains inhibition. In this paper, we prove exist of inhibitory substances and their activities through extracting, removing the inhibition substance of walnut seed. The results establish the elements for confirming the kinds of inhibitory substances, and provide theory base for confirming the fitting way of seed pretreatment before insemination. The main findings as follows:1. Using petri dish-filter paper method, determining the activity of endogenesis inhibitory substance of water extractions from different parts of dry walnut seed. The results show that there are definite inhibitory substances both in walnut shell and kernel, the inhibition activity of extract from kernel is stronger than extract from shell. Both extracts inhibit the rape and wheat seed germination and seedling growth, and the more concentration of extracts the stronger of inhibition effect.2. Determining the chlorophyll content of wheat seedlings,vitality of seedling roots,coleoptile elongation of wheat andα-amylase activity of wheat through spectrophotometer,chloridized 3-phenyl tetrazolium method,ABA wheat bud sheath identifying method,3,5-dinitrosalicylic acid, the results show that:①the chlorophyll a and chlorophyll b content of seedlings which treated with extract of walnut shell and kernel reduce as accretion of the extract concentration, when kernel concentration is 0.40 g·ml-1,the content of chlorophyll a and chlorophyll b are all zero.②Extract from walnut shells and kernels inhibit the energy of wheat roots andα-amylase, the more concentration of extract the stronger of inhibition effect.③The more concentration of extracts from walnut shells and kernels, the stronger of inhibition on coleoptile length of wheat. When extract concentration of kernel is 0.40 g·ml-1, coleoptile elongation of wheat treated is zero.3. Using biological way and paper chromatography, determine inhibitory effects of polarity and non-polarity substances from walnut seeds which used before and after stacking sand-hidden. The results show that:①After the stacking sand-hidden, the inhibition effects of the extracts from walnut shells and kernels are obviously weaken on wheat seeds germination and younger seedling growth, and the longer the time of stacking sand-hidden, the inhibition effects are weaker.②the polarity substance in water extracts has stronger inhibition than the non-polarity substances, the result explains that the polarity substance from walnut seeds has stronger inhibition. After the walnut seeds are sand-hidden, the content of inhibitory substances is markedly reduced, and the inhibition effect gets weaker.4. Through presoaking,flushing in flowing water and dipping in solvent etc, the inner inhibitory substances were removed. The results show:①When walnuts was treated in different temperature water, the extracts from different treatment all have the inhibition on wheat seed germination and seedling growth, the extract from walnut seed soaked by 40℃water has the strongest inhibition, so the treatment of 40℃water soaking is best way in removing inhibitory substances of walnut seed.②Treating the walnut seed by flowing water, when treatment time is 15 days, extracts from walnut shell and kernel have less inhibitory effect on wheat seed germination and seeding growth. The longer the flowing water flushes the weaker the inhibition of extract.③Using the different solvent soak walnut shell and kernel, the extracts all inhibit wheat seed germination and seedling growth. The inhibition on seed germination is weaker than on seedling growth. The inhibition of the acetone extract is the strongest in five solvents, next the inhibitions are the methanol extract, the 95% ethanol extract, the distilled water extract, the petroleum aether extract in turn. The factors of treatment method, cost, feasibility etc was considered synthetically in the practical production, we think that the 40℃water presoaking and flushing in flowing water are feasible ways of walnut seed pretreatment before insemination.