. Bacteria in relation to plant diseases. Bacteria; Plant diseases. 22 BACTERIA IN RELATION TO PLANT DISEASES. made on each leaf, some in the midrib, but the majority in the tissue on either side of it. The pricked area covered about 4 sq. cm. Three subcultures from as many separate yellow colonies on the plates poured from the Australian cane were used. Many leaves were pricked as checks, but these never developed any disease. Until nightfall the inoculated leaves were protected from the light by paper, but the air was not shut off. A semitropical temperature was maintained in the greenhouse
. Bacteria in relation to plant diseases. Bacteria; Plant diseases. 22 BACTERIA IN RELATION TO PLANT DISEASES. made on each leaf, some in the midrib, but the majority in the tissue on either side of it. The pricked area covered about 4 sq. cm. Three subcultures from as many separate yellow colonies on the plates poured from the Australian cane were used. Many leaves were pricked as checks, but these never developed any disease. Until nightfall the inoculated leaves were protected from the light by paper, but the air was not shut off. A semitropical temperature was maintained in the greenhouse and the plants grew rapidly, an important factor. Three weeks after the bacteria were introduced by the needle-pricks the inoculated leaves showed white stripes, in which reddish or brown dead spots and stripes soon appeared. These stripes had their beginning in the inoculated part of the leaf and slowly spread upward and downward. For some weeks there were no further signs of infection; then white stripes appeared on other leaves (uninoculated ones on the same shoots) and, somewhat later, the red or brown stripes, with shriveling of the leaf-parenchyma. At this time the plants were considerably dwarfed, and this nanism finally became very marked (fig. 15). The condition of these plants at the end of two months (April 3) was as follows: (1) The leaf 1 b is dead from the punctures down to the stem on each side of the midrib. The distance from the pricked area to the top of the sheath is 19 inches. The length of the sheath itself is about 1 foot. The leaf is dried out on the margins and brown above the pricked area for a distance of feet. The terminal one foot of the leaf is bright green, and the midrib is green throughout its whole length. The signs on leaf / a, which is about the same length as the other, are the same, namely, dry brown margins about inch or more in width extending down to the sheath and upward to within a foot of the tip. The only marked difference in
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