. How crops grow. A treatise on the chemical composition, structure, and life of the plant, for all students of agriculture ... Agricultural chemistry; Growth (Plants). THE ASH OF PLANTS. 191 exists in comparatively large quantity. In tiie dense teak wood, concretions of phosphate of lime have been noticed. Of a certain species of cactus, {Cactus senilis,) 80" I,, of the dry matter consists of crystals, probably a lime salt. That the quantity of matters thus segregated is in some degree proportionate to the excess of them in the nourish- ing medium in which the plant grows has been observ
. How crops grow. A treatise on the chemical composition, structure, and life of the plant, for all students of agriculture ... Agricultural chemistry; Growth (Plants). THE ASH OF PLANTS. 191 exists in comparatively large quantity. In tiie dense teak wood, concretions of phosphate of lime have been noticed. Of a certain species of cactus, {Cactus senilis,) 80" I,, of the dry matter consists of crystals, probably a lime salt. That the quantity of matters thus segregated is in some degree proportionate to the excess of them in the nourish- ing medium in which the plant grows has been observ- ed by ISTobbe & Siegert, who remark that the two por- tions of buckwheat, cultivated by them in solutions and in garden soil respectively, (p. 188,) both contained crys- tals and globular crystalline masses, consisting probably of oxalates and phosphates of lime and magnesia, depos- ited in the rind and pith; but that these were by far most abundant in the water-iolants, whose ash-percentage loas twice as great as that of the land-plants. These insoluble substances may either be entirely unes- sential, as appears to be the case with silica, or, having once served the wants of the plant, may be rejected as no longer useful, and by assmning the insoluble form, are re- moved from the sphere of vital action, and become as good as dead matter. They are, in fact, excreted, though not, in general, formally expelled be- yond the limits of the plant. They are, to some extent, thrown off into the bark, or into the older wood or pith," or else are virtually en- cysted in the living cells. The occurrence of crystallized salts thus segregated in the cells of plants is illustrated by the following cuts. Fig. 23 represents a crystallized concretion of oxalate of lime, having a basis or skeleton of cellulose, from a leaf of the walnut. (Payen, Chimie Industrielle PI. XII.) Fig. 24 is a mass of crystals of a lime salt, from th^ leaf stem of rhubarb. Fig. 25, similar crystals from the
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectagricul, bookyear1868
