Inhibition Of Barnyard Grass Microbial Strains A And Mechanism

Allelopathic rice is a kind of special germplasm resources inhibiting grass, indirectly regulated by the microflora in the rhizosphere, so is one of the important soil resources to study the function of microbial screening suppression grass. This article aimed to screen a strain A with a grass suppression ability from allelopathy rice rhizosphere soil by morphological and molecular biological methods. Then the strain of grass suppression ability, enzyme production rules, grass suppression mechanism and safety, etc, were studied and analyzed. In addition, for the further development of the strain used to provide the theoretical basis of herbicide and industrial base. The main results are as follows:1. Classification and Identification of strain AThe colony morphology, microscopic observation of mycelia and the combination of molecular biology of the screening strain A were classified. The results showed that the strain A belongs to Aspergillus.2. Determination of grass suppression capabilityA strain of liquid and solid fermentation culture filtrate was prepared, and was determined by agar culture and pot culture method on the barnyard grass, rice growth inhibition rate and barnyard grass, rice mortality. Experimental results show that the agar culture broth at high concentration is on the growth of barnyardgrass promoting effect but at low concentrations inhibiting the growth of barnyard grass and barnyard grass on mortality is obvious, in addition the growth of rice and Mortality is not obvious; Pot culture with different concentrations of fermentation broth inhibition of barnyard grass in different, diluted 300 times in the highest inhibition rate Over 70% and mortality of barnyard grass at this time the greatest impact. Although the concentration on the growth of rice has some inhibitory effect,it does not affect the normal growth and development of rice and mortality.3. Analysis of enzyme series and the elementary discuss of its restraining E.crusgalli of the restraining-grass strain A In this article the strain A was cultured in the liquid medium and sampling in the designated time,Analyzed of the producing-enzyme type and rule of the strain A.The mechanism and evaluatation of the strain A broth that can restrain the growth of E.crusgalli was discussed too.The results showed that:Strain A can produce CMCase, P-glucanase, chitinase, amylase,pectinase,xylanase, proteinase,and other extracellular enzyme during the cultivation.the activity of this enzyme changed during the cultivation:the strain A started to produce enzyme 48h later and reach the high point in the 72h. the effection of fermentation fluid to the root and leaf cell of rice and E.crusgalli indicated that:the Strain A broth has no apparent impact of inhibition or activation on the key enzymes and protective enzymes in the growth process of rice.But it can influence the protection enzymes and key enzymes of E.crusgalli, especially to ATP, SOD, POD, GSH-Px and GTS.The inhibition rate of ATP,SOD, POD, GSH-Px and GTS reach 41.36%,69.31%,42.11%,60.14% and 69.48% respectively. By inhibiting the key enzyme of E.crusgalli in the growth process, the Strain A broth improves the content of the MDA to influence the growth of E.crusgalli, even more makes it grows slow or die.4. Safety assessment of strain AA fermentation filtrate of strain inhibited the growth of barnyard grass. In order to further clarify their position on the growth of rice and other crops, we should assess impact of its security. The results showed that the fermentation filtrate can promote the germination of rice seeds, but the seed germination of barnyard grass can also be promoted, so before the vaccine strain A is not appropriate for the prevention and control weeds. Treated in different ways and different from the culture filtrate through the filtrate concentration on the growth of barnyard grass after germination inhibition different spraying diluted 100 times in the liquid fermentation extract the maximum inhibition of barnyard grass, the best result, the death of barnyardgrass rate of up to 80%.Various fermentation filtrate of rice were not significantly inhibited. Filtrate of rice seedlings were significantly promoted the growth and the growth of corn and sudangrass showed a certain role in promoting high concentration (diluted 100-300 times) on the growth of wheat showed some inhibition, the concentration of more low (greater than 300-fold) but showed some catalytic role. A whole fermentation broth of strains of rice and most of the crops are safe, that further application for the strain A provides a scientific basis.