. Bacteria in relation to plant diseases. Bacteria; Plant diseases. BROWN ROT OF SOLANACEAE. 199 ^ A a - B 3 Fig. !I0.! in steamed potato cultures, especially if the brown stain is well developed, and the well- browned colonies on agar are usually dead. Two weeks is about the limit of vitality on cooked potato; sometimes cultures were dead at the end of one week. An actively motile bouillon-culture frozen in liquid air for 20 hours was still motile upon thawing out. Exam- ined in a hanging drop within 20 minutes hundreds of the rods were active. This was not a Brownian movement, but a rapid da
. Bacteria in relation to plant diseases. Bacteria; Plant diseases. BROWN ROT OF SOLANACEAE. 199 ^ A a - B 3 Fig. !I0.! in steamed potato cultures, especially if the brown stain is well developed, and the well- browned colonies on agar are usually dead. Two weeks is about the limit of vitality on cooked potato; sometimes cultures were dead at the end of one week. An actively motile bouillon-culture frozen in liquid air for 20 hours was still motile upon thawing out. Exam- ined in a hanging drop within 20 minutes hundreds of the rods were active. This was not a Brownian movement, but a rapid darting motion which often carried the rods out of the field. However, a distinctly less number seemed motile than before the exposure and poured plates (Vir- ginia organism) demonstrated 50 per cent to be dead. The organism grew well in acid bouillon ( + 33, acid of beef juice), but less rapidly at first than in nitrate bouillon (+15). After 3 months the bouillon was stained brownish. There was then an interrupted, dirty, gray-white pellicle, a dirty, brownish-white precipitate, and numerous small crystals. The Virginia organism did not grow well on No. 602, a rather acid agar made from the juice of sugar-beets diluted with water. The Virginia organism after growing in peptonized Uschinsky's solution for from 9 to 14 days had developed no pellicle, rim, or pseudozoogloese, but only a thin clouding, with a small amount of brownish-white precipitate. Around the surface growth, in the agar in contact with the air, a white amorphous sub- stance develops. This substance is finely granular under the microscope and dissolves in acetic acid. There appear to be many degrees of virulence, and possibly there are several strains of the organism. RESUME OF SALIENT CHARACTERS. POSITIVE. Cause of a vascular disease in solanaceous plants—potato, tomato, egg-plant, etc.—and from recent studies by Honing and others it would seem also of a disease in plants of several other families. vShort ro
Size: 1544px × 1617px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherwashingtoncarnegie
