Effects of Light Quality on Growth and Mineral Nutrition of Bean

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Abstract
Red kidney bean (Phase-lus vulgaris) plants were grown under fluorescent lamps of various colors. Dyed gelatin filters were used with some lamps to narrow the spectral regions used. Plants under each of the lamps received equal amts. of energy as measured with a thermopile. The lengths of hypocotyls and first internodes were least in plants receiving light from nearly all parts of the visible spectrum. If only plants which received energy from rather narrow regions of the spectrum were considered, the effectiveness in inhibiting elongation was greatest in the red and least in the blue regions. Leaf area and dry wt. production were greatest in plants receiving the more balanced radiation. Leaf area was least in green light and slightly greater in red than in blue. Dry wt. production was also least in green but nearly equal in the red and blue regions. No significant differences in the amt. of ash, or in the % of K or Mg in the ash, were found in plants grown in different . light quality. The ''% of Ca in the leaves was highest in plants which received the more balanced radiation and lower when narrower regions of the spectrum were used. When the Ca content of the leaves was high, the content of the stems was low, and vice versa. Removal of the red or blue end of the spectrum resulted in plants which were higher in P than those grown in more balanced light. Removal of both ends of the spectrum resulted in still higher P content.