| Popis: |
1. Three series of plants were grown and each series was divided into three sets. All the conditions of the three sets of one series were identical with the exception of the range of wave length of ultraviolet radiation received. 2. The amount of growth of the plants was determined by measuring the dry weight. The calcium and phosphorus intakes were also determined for these plants grown in the three different ranges of wave length. 3. The region of ultraviolet between 2900 and 3100 A. apparently caused, under the conditions of these experiments, an increase in the dry weight of all the plants grown with the exception of corn. Plants receiving no wave lengths shorter than 3100 A. were considered as controls. 4. This same region of ultraviolet (2900-3100 A.) apparently caused an increase in percentage of calcium in all of the plants grown. No conclusions could be drawn from the results as to the effect of these wave lengths on the phosphorus content. 5. The presence of wave lengths shorter than 2900 A. cau... |
