Study Of Mechanisms On Induced Resistance Of FOC-RA-5 To The Cucumber Wilt

It was conducted that germinated seed of cucumber at the time of radicle length of about 0.5 cm (soaking the radicle) and the first leaf width about 5cm (root irrigation) were induced two times with the nonpathogenicity FOC-RA-5, that treated with sterile water as the control. Then, the leaves were randomly selected every 24 hours as the test materials. These materials were used to measure cucumber phenylalanine ammonia lyase (PAL)、 polyphenol oxidase (PPO)、peroxidase (POD)、catalase(CAT)、superoxide dismutase(SOD)、(3-1,3-glucanase、 chitinase、carboxymethyl cellulase、β-grape glycosidases、Lipid peroxidation (LOX)、ascorbate peroxidase (APX)、indole acetic acid oxidase (IAAO) and nitrate reductase (NR) activity in order to study the mechanism of induced resistance, which refered to the attenuated strain of fusarium wilt of Cucumber against fusarium wilt of cucumber. The results showed that:1. The results of field pathogenicity of Fusarium Wilt of Cucumber showed that the disease index of cucumber seedlings which were induced with FOC-RA-5 and then inoculated with FOC was 9.73, the disease index of the control was 31.79, treatment and control of disease rate were 24% and 67%, and the prevented effect was 69% compared with the control.2. The treatment and control of enzyme activity were analyzed by t test. There were differences reached significant level (P< 0.05) which were induced enzyme activity LOX, APX, NR, PAL, PPO, POD and carboxymethyl cellulase, there were differences reached extremely significant level (P< 0.01) which were induced enzyme activity PPO, SOD, (3-1,3-glucanase and chitinase activity,there were not differences reach the significant level which were induced enzyme activity CAT, indoleacetic acid oxidase and β-glucosidase activity.In addition to carboxymethyl cellulase、SOD and β-glucosidase, NR、APX、POD、 PPO and PAL treatment of the enzyme activity were significantly higher than that of the enzyme activity.3. There were first increased and then decreased which were induced enzyme activity LOX, PAL, PPO, POD, CAT, SOD and chitinase, indole acetic acid oxidase, β-1,3-glucanase in the leaves of cucumber. There were first decreased and then increased which were induced enzyme activity APX, NR, carboxymethyl cellulase, β-glucosidase.4. The leaves of cucumber CAT, SOD, APX, LOX, PPO, POD, PAL, chitinase, β-grape glycosidases and β-1,3-glucanase activity between induced disease index of cucumber plants was negatively correlated.Indole acetic acid oxidase, carboxymethyl cellulose,nitrate reductase activity between induced disease index of cucumber plants into positive correlation.