Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplant00tube Year: 1897 140 ASCOMYCETES. cell-nucleus. This tissue so formed may be compared to the nutritive tissue formed secondarily from parenchyma as a result of other fungoid diseases, in violas attacked by Urocystis violae. If the formation of sporangia ensues in parts which would normally become collenchyma, the tissues there remain thin-walled. The sporangia of rrotomyccs, according to De Bary, begin to develop
Diseases of plants induced by Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae diseasesofplant00tube Year: 1897 140 ASCOMYCETES. cell-nucleus. This tissue so formed may be compared to the nutritive tissue formed secondarily from parenchyma as a result of other fungoid diseases, in violas attacked by Urocystis violae. If the formation of sporangia ensues in parts which would normally become collenchyma, the tissues there remain thin-walled. The sporangia of rrotomyccs, according to De Bary, begin to develop as soon as the young leaves and shoots of the host- plants emerge above the ground in spring. The sporangia first Fio. 47. — Protomyces -inacrosporui. Section through swollen leaf-stalk of Aego- poiUuni. Towards the right end the cells are normal, elsewhere they are, under the influence of the mycelium, much enlarged and sccoudarily divided ; two roundish sporangia lie in this tissue, (v. Tubeuf del.) appear as series of swellings on the hyphae and are easily detected in deformed plants as large thick-walled bodies lying in the intercellular spaces. They are liberated on decay of the host-plant, and in spring the contents swell up so as to rupture the thick outer wall, and the endosporium emerges as a vesicle or sporangium into which the protoplasmic contents pass to form numerous rod-shaped spores. The spores are ultimately expelled with considerable force, and, after conjugating in couples, they send forth a germ-tube which penetrates again into the tissues of the host-plant. ' De Bary, Beilriuje z. Morph. u. Physiol, d. Pilze, also Botan. Zeltimg, 1874.
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