On Allelochemicals And Allelopathic Mechanism Of Sainfoin Root Exudates

Allelopathy, Allelochemicals,rhizosphere microorganisms and Allelopathic Mechanism of Sainfoin root exudates have be studied on this experiment. For to use the Allelopathy of plant to control the weeds in agriculture, to exploit the new natural herbicide, to utilize natural resources more effectively and sensibly, and for to develop sustained agriculture theory. The results as follows:1. The test of the sainfoin root excudation's allelopathy effect to seven receptor plantsUsing tissue culture, exudation was extracted from sainfoin's root, and studied exudates'allelopathy effect to the seven plants by biological assay. Sainfoin root exudates had inhibition on root germination, seedling root growth and plant height. The results showed that the same receptor plant had different sensitive effect for the different treatment concentration.The inhibition of sainfoin root exudates gradually significantly for the root germination of seven receptor plants, and the inhibition effect was maximum when concentration was 100mg·ml-1; and the same treatment concentration had definitely Interspecific difference. The average inhibition rate of four treatment concentration showed that sainfoin root exudates had stronger inhibition to ash pigweed, annual bluegass, amaranthus, rye grass, the aveage inhibition were respectively 62.72%, 53.79%, 51.43%,51.43%; but the inhibition was weaker to Nightshade, tall fescue, bristlegrasses. And sainfoin root exudates had stronger inhibition effect to plant radicle than stems and leaves.2. Sainfoin root exudates affected rhizosphere microorganismsbacteria was predominant group of sainfoin rhizosphere microorganisms, its mainly distruibuted 10~20cm cultivated horizon. Fungi, bacteria, actinomycetes reached maximum in august when the average temperature of soil was highest. And the total soil microorganism of the triennial sainfoin land were more than biennial and annual land; and the total bacteria >the total actinomycetes>the total fungi.3. The mechanism of allelopathic inhibiting effect to seven receptor plants from sainfoin root exudates. Determined Sainfoin root exudates affected some enzymes in seven receptor plants with different concentration. The result indicated that the activity of the hyperoxide mutase (SOD), the peroxide enzyme(POD), the catalase (CAT),ascorbate peroxidase (APX) and soluble protein content (Pr)were decreased by allelochemicals of sainfoin root exudates. These enzymes cut down the resistance and inhibited the growth of receptor plants. As a result it showed strong allelopathic ability.