【摘要】 以室内和田间相结合的方法、病理和生理相结合的手段,进行了NS-83诱导抗性机制的探讨。室内试验表明,NS-83具有体外钝化TMV、抑制TMV初侵染的作用,经根部吸收可降低叶部的侵染;可诱导与抗性相关的细胞分裂素和过氧化物酶活性的增加。田间试验结果表明,在不同地区的番茄、辣椒、烟草上NS-83均具有降低发病率的抑制侵染作用和压低病情指数的治疗作用,推迟了田间发病。更多还原

【Abstract】 The formerly reported virus-tolerance inducer NS-83 has been further studied at this laboratory as well as in fields. It has been revealed that NS-83 is not only a virus-tolerance inducer, but also, to a certain extent, a virus-resistance inducer. So far us tested on detached Xanthi-nc tobacco, the NS-83 treated TMV in vitro reduced 65.1%-84.8% of the lesions produced. It was also effective on the inhibition of primary infection that a spray of NS-83 on the leaves of living tobacco plants 24 hr and 48 hr before inoculation of TMV, the reduction of lesion numbers was 73.9% and 68.3% respectively. After a solution of the F. I. fraction of NS-83 had been absorbed by the tobacco roots for 24 hr, TMV was inoculated onto the upper leaves of beth the treated and non-treated tobacco plants. The number of lesions produced on treated plants was reduced to 60.4% of the control. In field tests, the plants were sprayed with the preparation of NS-83 (with a concentration 1 /100), once at seedling bed stage and another at the time shortly after planting. The results showed that 22.9%-67.6% of the disease incidence were reduced for chilli pepper, 35.6% for tobacco, and 33.3%-73.9% for tomato in fields in different local cities. On the basis of the disease index estimated in the fields for tomato, chilli pepper and tobacco plants so far sprayed with NS-83, the therapeutic effects of the resistance inducer on the TMV infection were 82.4%, 26.3% and 83.3% respectively. Furthermore, it was observed that the occurrence of the TMV infection peak on tobacco plants was delayed 20 days in comparison with that of the non-sprayed plots. Results of biochemical analysis revealed that when the tomato plants were sprayed with NS-83, 49.8% increase of endogenous cytokinins was detected in the plant extracts, while the peak increase of peroxidases happened one week after inoculation, just at the time of acceleration of virus multiplication. The quantity of endogenous cytokinins and peroxidases in pland cells were previously demonstrated to be intimately correlated to the virus disease resistance and tolerance. However, the mechanisms pertaining to the induced disease resistance and tolerance remain to be studied.更多还原