| Triclioderma viride Persoon strain Tv-1 was isolated from soil by Dr. Wang Ge who worked in Hongta Group.This strain grew fast and controlled fungous diseases of tobacco effectively.The solid fermention preparation of T.viride strain Tv-1 has been in production.Understanding the ecology characterristics of T.viride strain Tv-1 clearly especially relative to colonization.is important to know the colonization mechanisms and promote its colonization efficiency.The experiment by the method of immersed piece results showed that T.viride strain Tv-1 could grow and reproduct fast along the root of tobacco.The colonization number of T.viride strain Tv-1 near to soil surface was more than that on other section of tobacco.The adhesion experiment results indicated that T.viride strain Tv-1 showed obvious topotaxis to tobacco seedling.The ones near to tobacco grew much better than those far from tobacco.The crude conidia suspension of T.viride strain Tv-1 was able to agglutinate with crude lectin of tobacco,vvhich suggested the colonization capability of T.viride strain Tv-I. T.viride strain Tv-I could product cellulase and the highest peak of carboxymethyl cellulase(CMCasc) and filter paper cellulase was 149.35 n g/ml.min and 255.60 u g/ml.min.A lot of reserches reveaed that the cellulase activity was positively correlated to colonization capability of biocontrol agents.The antagonistic experiment of by T.viride strain Tv-1 and Phytophthora strain Phi showed that the action mode of antagonisms included niches and nutrition competion and hyperparasitism.Whether or not the biocontrol agents are able to colonize on plant is an important evaluation index.The experiment samples were taken at regular intervals and were observed by Scanning Electronic Microscope.The results illustrated that T.viride strain Tv-1 was able to adhere to tobacco sifnificantly,which was the first and important step for colonization.The colonization of external rhizosphere act as the an inocula for second colonization.The major suitable colonization niches of Tv-1 were the base of root hairs.natural openings,wound.the base of glandular hairs of stem and phylloplane,around stoma and recessed of phylloplane,where there were much more metabolins.And T.viride strain Tv-1 was able to penetrate into root and stem in some suitable niches and conducted in a short distance.The consduction capability showed the potential of competing space and nutrition with pathogy within tobacco of T.viride strain Tv-1.The colonization number of T.viride strain Tv-1 on the root and phylloplane of tobacco was measured by Trichoderma Semiselective Medium(TSM).The results showed that the colonization number of T.viride strain Tv-1 was stable,but the number were always bellow the original one.The phenomena perhaps showed the soil mycostasis and population competetion and bad adverse circumstances.The colonization of T.viride strain Tv-1 was influenced by many facors.The factorsaffecting colonization of T.viride strain Tv-1 on the tobacco root were studied by testing on the agar plate. The isolation and counting of strain Tv-1 were performed on 7hc/ifera-Semiselective Medium(TSM).The results demonstrated that the following factors,including moisture,nutrition,pH and varieties of tobacco influenced the colonization ability of strain Tv-1 on root. 97.0% moisture on the agar plate ,the pH ranging from 4.0 to 6.0 and glucose as the carbon sources were optimum conditions for the colonization of strain Tv-1,and Yunyan85, G28 and NC89 were most favourable tobacco varieties for the colonization of strain Tv-1 on the root of tobacco.The colonization of T.viride strain Tv-1 did not hamper the growth of tobacco.Inversely, T.viride strain Tv-1 was able to promote the growth of tobacco to some extent.The results showed that the photosynthetic rate chlorophyll content of tobacco with T.viride strain Tv-1 were higher than that of the control.And the respiration rate kept constant.The photosynthetic rate and respiration rate and chlorophyll content were 21.250mgCO2/dnr.hr,6.781... |
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