Autointoxication In Adzuki Bean Replant

Adzuki bean (Vigna angularis) with a short growth days, shade plant, resistance-acidityand good adaptability is a important bean crop in China, meanwhile it is also importantagricultural product in export, and yield and export amount is maximum all over the world.Replant problem was a key factor for restraining yield and quality in adzuki bean. Replant canincrease rate of disease infecting, which can reach by30%-80%. Therefore, there was animportant meaning for overcoming replant problem based on studying relationship betweenautotoxin and replant problem in Adzuki bean.Jihong9218was used as a material and analyzed the kinds and composition of autotoxinin different organs of adzuki bean by yield test and lab. Under manual simulation, we focusedon researching effect of reactive oxygen metabolism, soil microorganism, nutrition andenzyme variation, mineral nutrition and photosynthesis. The main results were as follows:(1)The leach liquor of different organs and root area in adzuki bean has negative effecton seed sprouting and seedling growth, and this effect was increasing with increasing leachliquor density. Autotoxin was site difference during seed sprouting in adzuki bean, and therewas significant autotoxin in leaf leach liquor. The order of negative effect in different organswas as follows: Flag> fresh leaf> soil> root> stem.(2) Different organs and soil leach liquor in root were measured by using GC-MSmethod. The results showed that: the kinds and content of allelochemicals had large differencein leaf, stem, root, root area. There were55,43,40,33kinds of chemical materials in leachliquor of leaf, root, stem, root area, respectively. Different organs and soil leach liquor hadsame allelochemicals, and they were phthalic acid, cinnamic acid, p-hydroxybenzoic acid,respectively. However, these allelochemicals had different content in different organs.According to bioassay, these materials had inhibitional effect for root growth in adzuki bean,and this inhibitional effect was increasing with increasing density. The order of negative effectwas as follows: phthalic acid> cinnamic acid> p-hydroxybenzoic acid.(3) Phthalic acid and cinnamic acid can restrain root growth, and this effect was increasewith increasing density, meanwhile phthalic acid had better negative effect than cinnamic acid.Phthalic acid had significant negative effect in dry weight of root, root length, root volume, root area, root vitality, the number of root nodule and root fresh weight under10m mol.l-1. Inadditional, abortive grain,100-seed weight and the pod number per plant had negative effectwith increasing density of phthalic acid and cinnamic acid. Compared with CK, grain weightper plant of adzuki bean was decrease by1.1g,2.1g,3.0g and2.6g,3.2g,4.3g by cinnamicacid processing and Phthalic acid processing, respectively. This result showed that phthalicacid had better effect on yield than cinnamic acid.(4) Phthalic acid and cinnamic acid can reduce activity of SOD and CAT. Activity ofSOD and CAT was increase in early stage and decreasing in later stage with increasing inprocessing time. In28days after seedling, activity of SOD and CAT were decrease by9.01%，18.45%，35.41%and14.59%，23.33%,31.57%by phthalic acid processing,respectively. Activity of POD and content of MDA were increase with increasing inprocessing density and stress time.(5) Phthalic acid and cinnamic acid had negative effect on content of chlorophyll, netphotosynthetic rate, stomatal conductance and transpiration rate, meanwhile they had doublenegative effect on intercellular CO2density, but there was no significant difference indifferent treatments. Under0.1m mol.L-1density, content of chlorophyll, net photosyntheticrate, stomatal conductance and transpiration rate were increase firstly and decrease latterlywith increasing stress time. Under10m mol.L-1density, content of chlorophyll, netphotosynthetic rate, stomatal conductance and transpiration rate were decrease gradually withincreasing stress time.(6) Compared with CK, the treatment of two autotoxins can decrease number ofbacterias, actinomyces and microorganisms in rhizosphere soil and increase number offunguses, meanwhile every treatment can decrease activity of CAT, protease, phosphatase andsucrase in rhizosphere soil. Invertin was taken as example, under the same density, activity ofinvertin was maximum in14-21d then decrease apparently with stress time prolong bycinnamic acid. In42days, activity of invertin was decrease by18.22%、29.35%,38.49%compared with CK in different density processing. There was the same trend by phthalic acidprocessing, and that decreased by23.48%，34.85%,49.71%, respectively. Under autotoxinprocessing, the number of bacterium, fungus, and actinomyces was vary in soil. The numberof bacterium and actinomyces were decrease, and the number of fungus was increase.(7) Phthalic acid and cinnamic acid can restrain nutrition to be absorbed in root ofadzuki bean. Under10m mol.L-1density, absorbing of P and K were restrained by twoautotoxins, which decreased use efficiency of P, K and had no significant effect on N.(8)Activity of root in adzuki bean was decrease in leaf leach liquor with drought stressincreasing, and drought and leach liquor had significant negative effect on activity of root in adzuki bean. Under high drought stress, there was significant difference (P<0.01) than CK intreatments of0.04g ml-1,0.16g ml-1in leaf leach liquor. Under nutrition stress, the content ofchlorophyll and activity of root in adzuki bean was significant difference (P<0.05) than CKunder treatments of0.04g ml-1,0.16g ml-1in leaf leach liquor. The content of MDA wasincrease with leach liquor density increasing, and MDA accumulated gradually. Comparedleach liquor with drought stress, there was more negative effect in K deficiency.