Studies on the physiological mechanism of maleic hydra-zide to the subterranean crops and seeds. (3)

Abstract

1. Ether extracts of the disk part and the in-ternal bud portion of onion bulbs during the ordi-nary sprouting period have been chromatographed separately and the chromatograms assayed using Avena coleoptile elongation method. In the inter-nal bud of onion bulb treated with MH, both grow-th promoting and inhibiting substances were found alike as those found in the untreated material. Si-milar tendency was also detected in the etiolated gram seedling. 2. Respiratory intensity of onions treated with MH did not show any difference from the con-trol throughout the rest period, but when the con-trol bulbs began to sprout and the rate of its respi-ration rose, the increase of respiration was sup-pressed in the disk part of treated bulbs to some extent and the decline of respiratory quotient was found at the same time. 3. Though the sprouting and the elongation of gram seeds were greatly inhibited when they were treated with MH, O2 uptake in the stem re-maind unaffected during a considerable period after the treatment. However, the respiratory quotient in the growth region of stems of the treated mate-rial was always lower than the control. 4. The experimental results with onion bulbs and gram seeds received MH treatment indicated that the growth inhibition must have been induced from the disturbance of respiratory mechanism, not the fluctuation of growth substances.