| The endophytic fungus Chaetomium globosum ND35strain is a kind of endophytic fungus isolated from healthy plants Populus tomentosa. C. globosum ND35shows its antagonism against many plant pathogens, and the secondary metabolites produced by C globosum ND35promote growth of plants and induce resistance to plant diseases. In this study the experiments of promoting growth of Arabidopsis thaliana, walnut and chestnut seedlings were treated by C. globosum ND35. Detection of plant growth regulating substance produced from C. globosum ND35in fermentation broth was conducted for promoting growth of plant. The experiments of promoting growth of cucumber seedlings were made using the ergosterol and gibberellic acid. The changes of defense enzymes activities of diseased poplar plantlets were investigated after inoculation with C. globosum ND35and R. solani Rs-1. After inoculation with C. globosum ND35, preliminary investigation were conducted for growth of cucumber seedlings and part physiological characteristic under drought stress. The results are as follows.The test of promoting growth of plant show that root length has increased27.21%, the number of lateral root has increased42.28%after Arabidopsis thaliana was infected by C. globosum ND35. The height of walnut seedling at the age of one year which inoculated with C. globosum ND35was28.96%higher than that of control treatment. The stem diameter at the site of ground was20.04%higher than that of control treatment. The stem diameter of Zaoshi chestnut seedlings at the age of three years grown25.58%higher than that of control. The stem diameter of Guanghua chestnut at the age of two years grown25.88%higher than that of control.Gibberellic acid (GA), ergosterol, zeatin, indolebutyric acid (IAA) ect. plant growth regulating substances were detected in fermentation broth by high performance liquid chromatography (HPLC). Test of gibberellic acid and ergosterol for promoting plant growth showed that the crude extracts of GA and ergosterol from fermentation broth of C. globosum ND35can significantly promote cucumber growth. The promote plant growth of the GA extracts was obviously higher than standard sample of GA on root length. The promote plant growth of the ergosterol extracts was significantly higher than standard sample on plant height.After inoculation with C. globosum ND35for two days, the poplar plantlets from tissue culture were inoculated with hypervirulence R. solani strain Rs-1. The defense enzymes activities were significantly influenced in host plants. The peroxidase (POD) activity of the group inoculated with C. globosum ND35alone at the third to forth day was higher than that of the group inoculated with R. solani Rs-1alone and control group. The enzyme activity of the group inoculated with R. solani Rs-1alone and inoculated with both R. solani Rs-1and C. globosum ND35began to rise at fifth day and reach highest at sixth day. At the fifth and sixth day, the POD activity of the group inoculated with both R. solani Rs-1and C. globosum ND35was10.01%and9.48%higher than the group inoculated with R. solani Rs-1alone. The polyphenoloxidase (PPO) activity of the group inoculated with C. globosum ND35alone was only higher than that of control group. At the fifth day, the PPO activity rise obviously. At the seventh day, the PPO activity of the group inoculated with both R. solani Rs-1and C. globosum ND35was18.59%higher than that of the group inoculated with R. solani Rs-1alone. After2days later, The phenylalnine ammonialyase (PAL) activity of the group inoculated with both R. solani Rs-1and C. globosum ND35was higher than the group inoculated with R. solani Rs-1alone. The PAL activity of the group inoculated with both R. solani Rs-1and C. globosum ND35and the group inoculated with R. solani Rs-1alone rise to highest at the fifth day. The antagonistic effect on R. solani Rs-1was48%by C. globosum ND35. This indicates that C. globosum ND35could improve resistance to damping-off caused by Rhizoctonia solani on poplar seedlings.The influence of C. globosum ND35for cucumber, the experiment was designed for5water gradient:30%,40%,50%,60%and70%of maximum water holding capacity. Investigation were conducted for cucumber growth index such as root length, shoot length, fresh weight and drought physiological charateristics such as malondialdehyde (MDA), proline, superoxide dismutase (SOD). The results showed that70%maximum water holding capacity existed significant difference on plant height and fresh weight between inoculation and non-inoculation with C. globosum ND3. Root length showed significant difference between30%and60%maximum water holding capacity. MDA, proline, SOD also indicated significant difference between30%and maximum water holding capacity. MDA was lower than control, proline and SOD were higher than control. C. globosum ND35showed significant difference on cucumber at the strong drought stress. |
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