. Cassell's popular gardening. Gardening. 100 CASSELL'S POPULAE GAEDEXIXG. soil may be altered in character, taken up and utilised ioj the plant. The phenomena also show very remarkably the interdependence of living or- ganisms of various natures one upon another, and upon mineral matters, and they give some hint of the changes and activity going on in that soil which the generality of people still look: on more especially, but very erroneously, as an illustration of fixity and repose. Solvent Action of the Roots.—Another means by which insoluble matters in the soil become taken up by the plan
. Cassell's popular gardening. Gardening. 100 CASSELL'S POPULAE GAEDEXIXG. soil may be altered in character, taken up and utilised ioj the plant. The phenomena also show very remarkably the interdependence of living or- ganisms of various natures one upon another, and upon mineral matters, and they give some hint of the changes and activity going on in that soil which the generality of people still look: on more especially, but very erroneously, as an illustration of fixity and repose. Solvent Action of the Roots.—Another means by which insoluble matters in the soil become taken up by the plant is explained by the solvent action exercised by the roots themselves. The tips of the roots above the root-cap, or the extreme ends of the root-hairs, come into close contact with the particles of soil, and then an acid exudation from the cell takes place, which imme- diately attacks the particles of soil, and aided by the water around it, effects the solution of the mineral matter which it contains. The solution is absorbed as fast as it is pro- duced, and so none is per- ceptible in the soil itself. It is, however, to be noticed that this acid exudation from the cell-wall is produced as a consequence of direct contact with smtable matter, but not otherwise, just as the gastric juice in the stomach of an animal is only produced when the glands which secrete it are directly stimulated by the presence of food. Summary.—So far then as we know at present, liquid food, or rather liquid materials capable of being converted into food, are introduced into the roots of plants in one or other of three ways—by direct osmotic absorption or diffusion, as in the case of water and substances dissolved in it; by the agency of "microbes," which turn the insoluble into the soluble ; and by the agency of the roots themselves in furnishing at the right moment, and in the right quantity, a proper solvent. The substances introduced into the plant by the roots are, first and foremo
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Keywords: ., bookcentury1800, bookdecade18, booksubjectgardening, bookyear1884
