Study On Morphology And Physiological Characteristics Of Trichoderma Harzianum H-13

Trichoderma which exists in the soil,plant root zone and leaf surface widespread is a typical rot fungi and it is an antagonistic bacterium of Agaricus spawn distress pathogens.So Trichoderma is used as biocontrol factors and attracts much attention of many microbiologists and learners on plant diseases.Contrasting method was made use of in this experiment.After culturing the mutant strain,main differences were concluded by colony,mycelia and cell morphology in contrast to the wild strain.From the assimilation,transportation and utilization of nutrients made by the mutant strain,the result was concluded that the assimilation for nutrient was controllable.From the kinds and quantity of target products,a conclusion was concluded that expression of some enzyme genes was enhanced.In this test,inoculated the mutant strain and the wild strain on the PDA medium plate respectively,culturing under 30℃for three days.There was round plaque appearing on medium plate,most mycelia on the plaque was white,and some parts of the plaque were light yellow because of synthesis of pigment. When touching the plaque,it felt so smooth and slimy.When Trichoderma was cultured in liquid medium,the mycelia looked ball-like and light yellow.When watched by common microscope,the mycelia ramified like fishing-net.When watched by scanning electron microscope,the spore of the wild strain was round and its surface was very rough.But the spore of the mutant strain was smooth,like a loaf of bread.According to the level of left glucose concentration in the fermentatioh liquid. The glucose level in the fermentation liquid of mutant strain was lower than the level in the fermentation liquid of wild strain.This conclusion confirmed that the mutant strain metabolized for carbon sources faster than the wild strain.When experiments of producing chitinase and cellulose were done,glue-like chitin and CMC were selected respectively as unique carbon source.By enzyme activity of chitinase and the size of the hydrogen circle of CMC,the fact that expression of enzyme gene of chitinase and cellulose was enhanced after being mutated by N~+ ion beam was found.And enzyme activity of mutant strain came up to 0.292U/ml,but the wild strain,merely 0.228 U/ml.So the optimum medium for production of chitinase was the previous medium plus 1.0%yeast extraction.Cellulase was another enzyme produced by Trichoderma.In this experiment,Trichoderma was cultured in medium in which CMC was a unique carbon source.According to the size of hydrogen circle of CMC,enzyme activity of mutant strain was higher than wild strain.The experiments as above confirmed that ion beam played positive effect on biological characters of Trichoderma.Inoculated the mutant strain for 20 generations, and the stability of heredity of Trichoderma was not on the wane.And the mutant strain assimilated and utilized nutrients more effectively.And enzyme activity and quantity of chitinase and cellulose of mutant strain were both on the increase.In a word,ion beam played an important role on promoting Trichoderma.The mutant strain is going to suit the surroundings better than the wild strain.And the characters of heredity of the mutant strain was more stable.And at the same time,the mutant strain could tolerate pH,temperature,and osmotic pressure much better than the wild strain.Above this all confirmed that the mutant strain was more suitable to be biocontrol factor.