Microscopic Observation on the Development of Puccinia striiformis in the Spikeand Stem of Wheat

摘要

The majority of germ tubes of the pathotype CYR32of Puccinia striiformis f.sp. tritici formed on the surfaceof spike organs of the susceptible wheat cv.Suwon 11 penetrated through the stomatal pore, onlya few germ tubes formed small appressoria over thestomata. In the lemma, palea and glume, the striperust fungus spread between the parenchyma cells closeto the inner epidermal layer, but the fungus did notdevelop between the thick-walled cells near the outerepidermal layer of these organs. In the awn and stem,spread of the stripe rust was confined to the intercellularspaces of the chlorophyll parenchyma, beneath theinvaded stomatal pore of the epidermis and the urediniosporesto be released disrupted the epidermis. In thecaryopsis, the spread of hyphae was restricted to theintercellular spaces of the pericarp cells.