Physiological Studies on Fructification of Peanut : 8. On the relation between the calcium in the fruiting zone and the formation of unfilled fruit.

Abstract

This report deals with the results obtained in the various peanuts relative to the evaluation of calcium movement from the vegetative tissue to the fruiting organs when the nutrient treatments which differential amounts of calcium were applied to the fruiting zone, to essential amounts of calcium in the fruiting zone required for fruit filling, and to the quantitative difference of fractional calcium in above treatments. The isolated methods as reported previously, were begun on the various peanuts, and the nutrient solutions which contained the following amounts of calcium were added at weekly intervals to the fruiting zone of 2.8 kg acid-washed sand throughout the experiment: distilled water, minus Ca, 20 mg. Ca, 40 mg. Ca, and 60 mg. Ca as the complete solution. Before the pegs had penetrated the sand of the fruiting zone, 0.3 mc. of radiocalcium was applied to the rooting zone of each plant. 1. It was found that in case of runner type the immature pods including the subterranean pegs were more numbered than the aerial pegs, and that in case of bunch types the aerial pegs were more numbered than the immature pods. So far as those varieties are concerned, the unfilled fruits were formated only on the plants of Virginia type, and bunch varieties of the same type were found to have a greater tolerance against the formation of unfilled fruit than the runner ones. The rate of calcium contents in the shell and seed of Spanish varieties was somewhat greater than that of Virginia and Valencia. 2. The levels of calcium amounts of the fruiting zone where the unfilled fruits were formated, were 20 and 0 mg per 2.8 kg sand for Chiba-74 (runner type) and Tachi-Rakkasai (bunch type), respectively. In Southern Cross (bunch type of small-seed), irrespective of the amounts of calcium in this zone there were not observed the yield of unfilled fruits. In general the differences in the concentration of calcium in the fruiting zone seemed to have greatly affected calcium contents of the shell in all varieties, except in Southern Cross. On the other hand, there were no considerable differences in calcium contents in the seed of the above samples, but the contents of Chiba-74 were apparently less than the other two bunch vatieties. When the calcium deficient treatments were given in the fruiting zone, the very active translocation of Ca45 was observed from the vegetative tissue into the shells and seeds of the above varieties, and the movement of the labeled calcium into the seed in the bunch varieties was found to be more active than in the runner one. With adequate calcium supplied in the fruiting zone, the shells and seeds of fully developed fruits contained very small amounts of labeled calcium. 3. In the shell, alcohol soluble calcium in the filled fruits of the bunch types did not show any difference in various calcium treatments of the fruiting zone, while on the other hand, that of the runner type seemed to have sensitively increased by the increasing supply of calcium in the fruiting zone. Additionally, there were high contents of calcium in the unfilled fruits, especially when they were due to the high concentration of calcium in the fruiting zone. Regardless of the various calcium levels of the fruiting zones, the shell was found to have almost the constant contents of acetic acid soluble calcium, excepting in the case of high calcium level in Southern Cross. The contents of HCl soluble calcium were increased by the increasing supply of calcium in the fruiting zone in any case, but in the minus calcium, it seemed to have the tendency that the shell having two unfilled seeds in the mature pod had lower contents of calcium than the ordinary shell. In the seed, each amount of alcohol soluble and acetic acid soluble calcium remained almost unchanged independently both of the increasing supply of calcium in the fruiting zone and of the types. [the rest omitted]