Comparative Physiology of Green and Albino Corn Seedlings.

Previous comparative studies of green, albino, and variegated plants have shown higher levels of soluble nitrogenous compounds and lower levels of protein nitrogen in albino or in variegated than in green tissues (6, 14). The soluble nitrogen level was reduced and the protein level was increased when carbohydrates were supplied to albino tissues and plants. Groner (6), on the basis of such findings, postulated that when the supply of carbohydrate from the endosperm of an albino corn seedling became limiting, the seedling would hydrolyze its proteins, utilizing some of the products of hydrolysis in metabolism. The soluble nitrogenous substances, notably some amino acids, that could not be metabolized were thought to accumulate. Respiratory studies with green and albino plants have yielded conflicting results. Lebedeff (8) reported that rates of respiration of albino corn seedlings were 17 % less than that of green seedlings. Schumacker (14) used various variegated dicotyledonous leaves and found lower respiratory rates in albino tissues. He attributed this difference to the lower reducing-sugar content of albino tissues. He found that the rate increased in both kinds of tissues when supplied with glucose. Greater increases occurred in the albino tissues. Groner (5) reported little difference in respiratory rates of green and albino corn seedlings. It seemed desirable to investigate further the respiration and the changes of various nitrogen fractions with the possible occurrence of proteolysis in the albino corn seedlings. The findings reported here are results of two studies: (a) a time-course study of the distribution of certain nitrogenous substances in lightand dark-grown green and albino corn seedlings and (b) some aspects of the intermediary metabolism of these tissues. This study has suggested new aspects of metabolism of albino tissues, none of which were investigated completely. Consequently, this paper should be considered as a preliminary study.