Induction And Biochemial Mechanism Of Wheat Resistance To Pucccinia Recondita Tritici With BION

Benzothiadiazole is a kind of active molecules. It can induce monocotyledon and dicotyledon to be aquired systemic resistance to many fungi, bacteria and virus diseases. Systemic aquired resistance (SAR) provides a new technology to control plant diseases effectively. BION, which ingredient is benzothiadiazole, was the first commercial inducer by Ciba-Geigy Corporation and it had been used on many host-pathogen models. But it has not been known on wheat leaf rust disease.In this research, the relative induction effect (RIE) was tested on wheat-Puccinia recondita f. sp. tricici (PRT) model after spraying with BION at the seedling stage. The quantification of O2- and acticity of superoxide dismutase(SOD),peroxide(POD), polyph-enoloxidase(PPO),phenyalanine ammonia lyase(PAL),β-1,3-glucanase,chitinase was determined at different interval after inoculation and induction. And the physiological and biochemical mechanisms of inducing resistance on resistant and susceptible cultivar were also discussed.The results showed that the optimum concentration of BION for resistance induction was found to be at 200mg/L. An interval of at least two days between BION induction and challenge inoculation was required for establishment of the induced resistance, among which a four-day interval gave the highest protection. The BION-induced resistance could last at least 14 days once induced.BION had not shown any direct inhibition activity to PRT in vitro. The induced resistance could be presumed from wheat. It could be deduced that BION was an elicitor and different from common fungicieds.The quantification of O2- and the acticity of SOD, POD, PPO, PAL, β-1,3-glucanase, chitinase in seedling leaves were analyzed after spraying with BION at 200mg/L and inoculation with PRT 4 days later. The results showed that the quantification of O2- and acticities of SOD,POD,PPO,β-1.3-glucanase.chitinase could be increased when it was induced by BION. The RIE was even better on susceptible cultivar (Thatcher) than resistant cultivar (TcLr28).The peak value of O2- quantification and SOD, POD, PPO activitiy in resistant cultivar appeared much earlier and higher than in susceptible one. The percentage of increasing of O2- quantification and SOD, POD activitiy in susceptible cultivar was higer than in resistant one after induction and inoculation. But the increasing percent of PPO activity in resistant wheat was higher than in susceptible one.The activity apex of β-1,3-glucanase appeared in the same time in resistant and susceptible cultivars, but it increased much more in resistant cultivar than in susceptible one.Although the peak value appeared much earlier in susceptible cultivar and it was not much higer than in resistant cultivar, the increasing percentage of chitinase in susceptible was higher than in resistant wheat.The PAL activity did not change on resistant cultivar and it was increased on susceptible...