. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. ltingreadjustment of the elements keeps the vital activities going, justas the falling of a weight may set and keep in motion a train ofwheels, etc, More than 90 per cent, of the energy released inrespiration appears as heat, and the remaining energy probablymanifests itself for the most part in chemical reactions attendanton growth, repair, secretion, and other constructive processes. The Storage of Water.—The need of plants for specialwater-storage tissues is not so general as
. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. ltingreadjustment of the elements keeps the vital activities going, justas the falling of a weight may set and keep in motion a train ofwheels, etc, More than 90 per cent, of the energy released inrespiration appears as heat, and the remaining energy probablymanifests itself for the most part in chemical reactions attendanton growth, repair, secretion, and other constructive processes. The Storage of Water.—The need of plants for specialwater-storage tissues is not so general as their need for tissuesin which to store food. Underordinary conditions water can befreely taken in from the soil whichserves as the water reservoir forplants. But plants of desert regionsor growing anywhere under xero-phytic conditions (conditions makingwater hard to get, as when it isactually scarce or difficult to absorbbecause of low temperature in thesubstratum, or because there aresubstances in solution in amountslarge enough to act as a poison or toretard the osmotic inflow into theroots) to which this. FIG. 106.—Cross section of leafof Mesembryanthemum Forskaliishowing a large part of the leafdevoted to the storage of water, a,water-storage cells; b, chlorophyll-bearing cells; c, crystal of calciumoxalate. (After Schimper.) reservoir is denied or more or less inaccessible, have hit upon various com-pensating devices. One of these is the water-storage is seen in its fullest development in succulent stems andleaves. In Mesembryanthemum Forskalii of the Egyptiandesert approximately one-half of each succulent leaf is made upof water-storage tissue (Fig. 106); and in epiphytic species ofCodonanthe growing on a dry substratum nearly three-fourthsof the fleshy leaf is occupied by cells devoted to the storage ofwater (Fig. 81). The fleshy stems of cacti and some Euphor-biaceae are largely composed of the same kind of tissue. Inthe leaves of Ficus elastica the pro
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