关键词: 遮光, 茶树, 黄金芽, 黄化

Abstract: To select biocontrol bacteria for preventing tomato wilt, the gradient dilution coating method and the plate confrontation growth method were used for screening biocontrol bacteria from the worm cast and identifying the best strain. A pot experiment was carried out to examine the effects of the selected strain on tomato wilt and the activities of defense enzymes. The results showed that the bacteriostatic rate of DX-25 against Fusarium oxysporum was 66.09%, which was initially identified as Bacillus velezensis, with preventing rate being 59.25%±0.43% in pot. There were four treatments in the pot experiment: control (CK), F. oxysporum (KW), biocontrol bacterium DX-25 (DX), and pathogen+biocontrol bacterium DX-25 (D+K). The superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), lipoxygenase (LOX), chitinase (CHT) and β-1,3-glucanase (GLU) were used as the indicators for disease resistance in tomato, to investigate the effects of inoculation of biocontrol bacteria on defense enzyme activities in tomato plants. All treatments significantly increased the activities of these enzymes in stem. The D+K treatment enhanced the activities of PPO and GLU. The time for peak in activity of PPO and GLU in the combination of pathogen and biocontrol bacterium DX-25 strain was 48 h and 24 h earlier than that of single inoculation withF. oxysporum or DX-25, respectively. Our results showed that the combination of DX-25 and pathogens could induce a faster resistance response of tomato plants.

Key words: yellowing., tea plant, Huangjinya, shading