NUTRITION STUDIES WITH CORN

Abstract

Corn plants are grown in sand cultures using a series of nutrient solns. with different proportions of K+, Ca++, Mg++, phosphate, nitrate, and sulfate. Leaf and stem tissues from each treatment were harvested separately and each fraction was analyzed for soluble and total content of K, Ca, Mg, P, N and S. The data were analyzed statistically as to the relation between the conc. of the nutrient ions in the substrate and their rates of penetration and accumulation in tissue of corn plants. The most important single condition concerned with the penetration and accumulation in the plant tissues of each of the elements investigated, was its absolute conc. in the nutrient sol. The content of any element in the tissues might be directly or inversely related to the conc. of other elements in the substrate, depending on certain of their known chem. properties and the nature and degree of their physiol. importance. Many of the interrelations between the accumulation of elements in the tissues and ionic substrate concs. support the hypothesis suggested by Hoagland et al. of ionic penetration; others apparently fail to do so. The general trends of these relations in stem tissues and leaf tissues are quite similar although the order of magnitude of values differs considerably. Some of the more important specific relations indicated by means of the statistical treatment of data are briefly given. Within the range of ion concs. in the culture solns. employed: Mg content of tissues was directly related to variations in the nitrate and Ca ion conc. in the substrate, high Mg content corresponding to high nitrate and high Ca ion conecs. and low Mg content to low concs. of these ions; Mg content of the tissues was affected in the opposite way by variations in the K+ concs.. Mg content of the tissues was unaffected by variations in the phosphate and sulphate ion cones. Ca content of tissues was directly affected by variations in the nitrate ion concs. in the substrate, but was unaffected by variations in the concs. of other ions in the substrate. K content of tissues was inversely related to variations in nitrate and Ca++ concs. in the substrate, but appeared to be comparatively unrelated to variations in the substrate concs. of other ions. N content of tissues was inversely affected by variations in concs. of K+ and Ca++ in the substrate, but was unaffected by variations in the conc. of other ions. P content of tissues was relatively unaffected by variations in the conc. of any of the nutrient ions in the substrate except by those of the phosphate ion itself. S content of tissues was inversely related to variations in the concs. of Ca and nitrate ions in the substrate, but was relatively unaffected by variations in the conc. of other ions.