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将大麦白粉菌(Erysiphe graminis f.sp.hordei)的毒性和无毒性分离菌接接种顺序接种于具有不同抗性基因的大麦品种。不亲和反应所诱导的抗性能降低毒性分离菌的侵染,相反亲和反应诱导的感病性其程度足以增加无毒性分离菌侵染抗性寄主的能力。互作的净效应与单由某一种毒性分离菌接种相比能减少分生孢子的产生最。分离菌之间的每一个互作取决于所采用的寄主品种、病原分离菌和接种次序。先接种无毒性分离菌再接种毒性分离菌常常最易观察到诱导抗性。若先按种毒性分离菌,诱导感病性常常更加明显。不过,在品种Wing上先接种无毒性分离菌,诱导感病性更加明显。在品种Hassan上,先接种毒性分离菌,虽常诱导感病性,但某些时候以先接种无毒性分离菌时诱导更强的感病性。在后一种情况下,尽管无毒性分离菌所致侵染相对较少,但所产生的孢子大多数是由无毒性分离菌形成的。某些事证表明,无毒性分离菌可获得侵染不亲和性寄主的能力。如果没有毒性分离菌的存在,经过几个世代以后这种作用就会消失。
Toxicity and non-toxic isolates of Erysiphe graminis f. Sp. Hordei were inoculated in sequence into barley varieties with different resistance genes. The resistance induced by the unaffinity reaction reduces the infectivity of the virulent isolates, whereas the extent of the susceptibility induced by the affinity reaction is sufficient to increase the ability of the non-toxic isolate to infect the resistant host. The net effect of interaction is to reduce the production of conidia by more than a single virulent isolate. Each interaction between isolates depends on the host species used, the pathogenic bacteria and the order of vaccination. Inoculation of non-toxic isolates followed by virulent isolates is most often observed to induce inducibility. If the first by the toxic isolates, induced susceptibility is often more obvious. However, non-toxic isolates were first inoculated on Wing to induce more pronounced susceptibility. In the Hassan cultivar, virulent isolates are inoculated first, which often induces susceptibility, but at some point inducing more virulence when inoculated with non-toxic isolates first. In the latter case, although relatively few infections are caused by non-toxic isolates, most of the spores produced are formed by non-toxic isolates. Some evidence suggests that non-toxic isolates gain the ability to invade incompatible hosts. Without the presence of toxic isolates, this effect disappears after several generations.