Responses of Erysiphe graminis germlings to contact with artificial and host surfaces.

摘要: Germling development by Erysiphe graminis f. sp. hordei was compared between conidia held in a simulated air-borne state on microthreads constructed from safety-line threads produced orb--weaving spiders (Araneus diadematus), and inoculated onto glass, agar, or living dead barley coleoptile epidermes. Suspended germinated but generally only multiple short germ tubes. Conidia coleoptiles, bathed beneath with 0.01 m Ca(NO3)2 solution, one tube second which elongated formed normal appressorium. On glass tubes were sometimes long less frequently than host epidermis. When transferred to they differentiated an single also so that the tip of contact leaf epidermal strip layed whilst conidium rested agar. Long more such controls had no This suggested stimulus causing elongation perceived through strip. Where made strip, appressoria where agar surface alone. The results indicate germlings develop distinct stages response particular stimuli.