La Rouille Commune du Caféier (Coffea Sp.): Étude du Champignon Hemileia Vastatrix Berk. et Br. Dans les Tissus Foliaires

Click to increase image sizeClick to decrease image size

SUMMARY

Common rust of the coffee-shrub (Coffea sp.): study of the fungus « Hemileia vastatrix » Berk, et Br. in leaf-tissues.—After the germ filaments of uredospores of Hemileia vastatrix penetrated by way of stomata, we have studied the development of the intercellular mycelium of this fungus, its localization in the mesophyll, its branches and its walled and dicaryotic structure. We have described the relations between hyphae and leaf-cells of the coffee-shrub such as rounding and close contact between the walls of both organisms which is sometimes maintained over long distances, emission of short and pointed oranches which go through the wall and formation of « internal appressorium ». We have studied the first developmental stages of a haustorium, while stressing the modifications suffered by the walls of both organisms and we have observed the differentiation of the protective coverings of the maturing haustorium such as the collar, the encapsulation, the extra-haustorial membrane and the sheath. We have studied the distribution of the haustoria in the mesophyll, their localization in relation to the host cell and their mother cell. We have observed the differentiation of intercellular hyphae into fruiting hyphae producing uredospores and their clustered discharge through stomata.