. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 307 cept the awn and rachis is entirely transformed into smut. In water and in nutrient solutions the spores germinate by a single promycelium, 1 to 3-septate, and often branched, but without sporidia. That infection is floral in loose smut of both wheat and barley was first shown by Maddox ^' and the fact was corrob- orated by Wakagawa,'* Brefeld ^* and Hecke.'^' " The my- celium has been demonstrated in the embryo by Broili.^^' The spores falling between the glumes germinate, penetrate the
. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 307 cept the awn and rachis is entirely transformed into smut. In water and in nutrient solutions the spores germinate by a single promycelium, 1 to 3-septate, and often branched, but without sporidia. That infection is floral in loose smut of both wheat and barley was first shown by Maddox ^' and the fact was corrob- orated by Wakagawa,'* Brefeld ^* and Hecke.'^' " The my- celium has been demonstrated in the embryo by Broili.^^' The spores falling between the glumes germinate, penetrate the ovary wall, and into the growing point of the embryo. The mycelium here lies dormant until the seed germinates, when it grows, keeping pace with the growing point throughout the season and finally invading the ovaries to produce its spores. The infection of the pistil, the penetration of the integuments and the nucellus and embryo sac was followed in microtome sec- tions by Lang.^^^ The embryo was reached by the mycelium some four weeks after infection of the pistil. In resting grains the my- celium is abundant in the scutellum as well as in all embryo parts except the roots. Cross inoculation by Freeman and Johnson'' from barley to wheat and the reverse gave negative results. The optimum time for infec- tion has been determined as the period of full bloom. U. perennans ;*- ^'^ Son in spikelets, more or less destroying the , , J r ' .. Fig. 222.—U. tritici, basal and mner parts, sometimes even running germination in down on pedicels, oblong, about 3-8 mm. in ^°d^?fd Cohn's length, with dusty, olive-brown spore masses; Keiieiman and myceUum perennial in perennial parts of host; spores chiefly subspherical or spherical, occasionally ovate to el- lipsoidal, usually lighter colored on one side, more or less minutely echinulate, especially on the lighter side, 5-8 n in length. On the tall oat grass throughout its range. U. rabenhorstiana Kiihn occurs on several species
Size: 1309px × 1908px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectfungi, bookyear1913
