ELECTRO-CULTURE OF PLANTS. The culture of plants under electric stimulus. It has long been known that plants respond to electric stimuli, and many investigations have been made to ascertain practical means of realiz ing the benefits of this force. The subject naturally divides itself into the direct use of the current. when applied to the seed, plant, or soil, and the use of the electric light. The Abbe Nollet seems to have been the first to notice that the germination of seeds could be hastened by electrifying them before planting. Later, Specnew stimulated, for a few minutes, moist seed of beans, peas. barley. and sunflower. after which they were planted. Such seed germinated in half the time required for untreated seed. His experiments were repeated at the Massachusetts Hatch Experiment Station, where the germina tion was accelerated and the total germinations increased. Direct experiments upon the growth of plants have been made, in which zinc and copper plates, connected by wires, were placed in the soil in which the plants were grown. or wires were run through the soil and connected with a battery or electric machine of sonic sort. The first method has been successfully tried in Eng land and Germany with the result that larger crops of peas, barley. and grass were obtained from electrified plots of ground. The second method has been tried many times, the experi ments of Warner at the Massachusetts Hatch Experiment Station being of this class. lit 1893 he grew parsnips, lettuce. carrots. turnips., beets, salsify, onions. peas. and tomatoes. The seed of most varieties germinated sooner, developed bet ter, and the tomatoes ripened earlier. where the soil was subjected to the electric current. The nearer the plants were to the electrodes the bet ter was the growth. Various forms of aecitunt lators of atmospheric electricity have been tried, With greater or less success. That atmospheric electricity influences growth is shown by the experiments of Cirandeau, who maize inside an insulated cage. The stalks were lima smaller than those receiving the effect of the elec)ieity of the air. The effect or advantage secured is
explained by the fact that the electric current induces more rapid ehanges in the seed and soil, or that electrified plants are enabled to take up carbon dioxide more rapidly owing to the treat ment.
The effect of the electric light has hem very fully investigated at the experiment stations of Cornell Cu iver-ity and West Virginia, the arc 11:_it being used at the former station and the incandescent lamp at the latter. In the case of plants grown under the electric light, the effect to lie exerted through the hastening and prolonging of the assimilation of the plants. A large number of vegetable and tbnver and foliage plants have been experimented upon. In the experiments with the arc light it was soon found that the naked light exerted an injurious effect upon many plants. This is believed due to the presence of ultra-violet ray:, the spectrum of the electric light being unlike that of sunlight. A glass screen, as an ordinary globe. was found to cut out the injttrions rays and to allow the bene ficial rays to pass through. Hanging an are light above a greenhouse had the same effect. By this method the flowering period of many plants was, in some eases. hastened, as with Easter lilies. being advanced as much as ten days, and the colors were more intense. With vegetables the best results were secured with lettuce, plants of which were forced a week or more in advance of those in the unlighted portions of the house. 1 his fact has been taken advantage of in a num ber of instances in the commercial forcing of lettuce. Similar results were obtained with the incandescent light at the NVest Virginia Experi ment Station.
The practical utilization of the electric light in horticulture seems at present limited to fo•c ing lettuce and flowers. With these. illumina tion for a month until midnight seems to give results commensurate with the expense. The whole subject is hardly beyond the experimental stage as yet. except as noted above. See ELEC. TROTAXIS ELECTRoTROPISM GERMINATION.