. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. SECONDARY INCREASE IN THICKNESS or all of the leaves have been formed, and tracheal tubes com- municating with these have been laid down in the stem, the cambium can devote itself more exclusively to the pro- duction of strengthening tissues, the need for which has been caused by the in- creased size and weight of the crown. The two differ- ent regions of a ring of annual growth are, there- fore, seen to be an ana- tomical expression of vary- ing physiological need
. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. SECONDARY INCREASE IN THICKNESS or all of the leaves have been formed, and tracheal tubes com- municating with these have been laid down in the stem, the cambium can devote itself more exclusively to the pro- duction of strengthening tissues, the need for which has been caused by the in- creased size and weight of the crown. The two differ- ent regions of a ring of annual growth are, there- fore, seen to be an ana- tomical expression of vary- ing physiological needs. Sometimes it happens that trees are stripped of their leaves by insects, and later become rehabilitated by the growth of buds that would under normal con- ditions, have lain dormant until the succeeding spring. It is then found that the new crop of leaves stimu- lates the production of a new ring of growth in the stem, much as would have happened the follow- ing spring if things had been left to their wonted. Fig. 25.—Diagram showing the relation of this year's leaves to the wood of the current year. course. In those tropical regions where there is no pronounced dry season and the leaves do not all fall off at once, but just a few at a time with gradual renewal, there is no ring of growth formed; but where in the tropics a decided dry period provides plants with too little water, the leaves drop off just as they do outside. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Stevens, William Chase, 1861-. Philadelphia, P. Blakiston's Son
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectplantanatomy, bookyea
