. Bacteria in relation to plant diseases. Bacteriology; Plant diseases. 286 BACTERIA IN TO PLANT DISEASES. vessels. The cells are separated from each other, crushed and dissolved (?) their place being taken by the rapidly multiplying bacillus (fig. 62). For an earlier stage of bundle infection see vol. i, fig. 9. In this way cavities arise which by fusion with other cavities lead to the honey-combing and more or less complete destruction of this part of the bundle and consequently to the interruption of its function, viz., the movement of water. The bacteria also pass outward through
. Bacteria in relation to plant diseases. Bacteriology; Plant diseases. 286 BACTERIA IN TO PLANT DISEASES. vessels. The cells are separated from each other, crushed and dissolved (?) their place being taken by the rapidly multiplying bacillus (fig. 62). For an earlier stage of bundle infection see vol. i, fig. 9. In this way cavities arise which by fusion with other cavities lead to the honey-combing and more or less complete destruction of this part of the bundle and consequently to the interruption of its function, viz., the movement of water. The bacteria also pass outward through the lignified tissues (by way apparently of the pits) into the large pitted vessels, several to man}'- of which are often filled partly or completely before there is any destruction of the phloem or of the general connective tissue of the stem. In the end, the bacteria may be found also in the phloem and outside of the bundles in the surrounding tissues. For an especially good example of a late stage in which the bacteria have passed beyond the limits of the bundle and may be seen occupying the intercellular spaces and the interior of parenchyma cells see fig. 81. By this time, however, the stem begins to shrivel from loss of water, and the activities of the organism cease, so that the phloem and the tissues lying between the bundles, or beyond them toward the periphery of the stem, are seldom occupied to any great extent. Frequently pitted vessels at the outer angles of the xylem become filled in advance of those in the middle. The lignified tissues are not dissolved, but the thin non-lignified membrane separating the pits on contiguous vessels must be ruptured or dissolved by the bacteriaâotherwise it is impossible to account for their diffusion into the connective tissue of the xylem and from one pitted vessel to another. It is very easy to demonstrate microscopically the presence of the bacteria in the vessels, to cultivate them therefrom (when the right methods are used)
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