Diseases of glasshouse plants (1923) Diseases of glasshouse plants diseasesofglassh1923bewl Year: 1923 CHAPTER VI DISEASES DUE TO BACTERIA Another class of micro-organisms which cause plant diseases are the bacteria. Plant bacteria are generally rod-like in form (Fig. 35), varying from one thirty- thousandth to one ten-thousandth part of an inch in length, and about a third of that in diameter. They multiply by dividing across the middle, each half becoming a separate bacterium. This process takes place so fre- quently that in a short time many millions of bacteria are produced from one orig
Diseases of glasshouse plants (1923) Diseases of glasshouse plants diseasesofglassh1923bewl Year: 1923 CHAPTER VI DISEASES DUE TO BACTERIA Another class of micro-organisms which cause plant diseases are the bacteria. Plant bacteria are generally rod-like in form (Fig. 35), varying from one thirty- thousandth to one ten-thousandth part of an inch in length, and about a third of that in diameter. They multiply by dividing across the middle, each half becoming a separate bacterium. This process takes place so fre- quently that in a short time many millions of bacteria are produced from one original parent. Certain bacteria may divide once every twenty minutes, and at this rate the progeny of one bacterium would exceed sixty-four thou- sand million ia twelve hours, were all the offspring to ,, yploai appearance of remain alive. Most disease- bacteria pathogenic to plants. producing bacteria possess a number of tiny ' tails ' or flagella, by means of which they are able to swim ui water. Some types of bacteria produce within their bodies hard, resting spores, capable of withstanding abnormal conditions, but bacteria causing diseases of plants are not known to do this. Bacteria are carried from plant to plant by wind, rain, insects, and animals, including man. Once on the plant they may enter the inner tissues by means of the stomata, or by wounds, and in this process they are 131
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