. Cyclopedia of farm crops. Farm produce; Agriculture. 120 THE SHADING OF PLANTS A general discussion of shading involves the following considerations: I. The Plant. (a) Direct effect on the plant. (6) Indirect effect on the plant through environment, (c) Kinds of plants with which the operation of shading may be employed. II. The Screen Mechanism. Laths and boards, cloth screens, plant covers. The plant. (a) Direct effect.—It must be borne in mind that plants are very differently adapted to light in- tensities. Some plants to a large degree are in- dependent of light conditions. Certain small
. Cyclopedia of farm crops. Farm produce; Agriculture. 120 THE SHADING OF PLANTS A general discussion of shading involves the following considerations: I. The Plant. (a) Direct effect on the plant. (6) Indirect effect on the plant through environment, (c) Kinds of plants with which the operation of shading may be employed. II. The Screen Mechanism. Laths and boards, cloth screens, plant covers. The plant. (a) Direct effect.—It must be borne in mind that plants are very differently adapted to light in- tensities. Some plants to a large degree are in- dependent of light conditions. Certain small fungi grow equally well in total darkness or in strong diffused light. The common mushroom, so far as the production of the fruit, or mushroom proper, is concerned, is uninfluenced by light, ex- cept in so far as light affects temperature and, thereby, evaporation. Among common green plants there are shade-loving and sun-loving species. In the shade of certain trees, no green plant may live constantly. In the deepest gorge the densest ferns may grow, and on the exposed cliff a grass or a heavy vine may find its suitable home. In considering the direct physiological effects of shading on plants, we may note the effect on (1) Color: Etiolation or blanching. (2) The form and size of the plant. (3) The minute structure, i. e., on the elements of the framework which have to do with texture and suc- culence. (4) The bulk of the plant, by reducing or modif yingthe products of growth. (5) The checking of nitrogen assimila- tion and albuminoidal synthesis. (6) Modification of the acid content, as well as the content of soluble carbohydrates. (7) The aromatic content in the plant juices, and other minor meta- bolic modifications affecting the quality of the product. (8) The development of flowers, fruits and seeds. (1) The effect on color is considerable. The intensity of the light will usually directly affect the chlorophyll development. In darkness most plants are soon etiolated, or
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