Leaf Catalase Activity varying with Growth of Wheat Plants including both of Spring and Winter Types

Abstract

The author examined the leaf catalase activity varying with the growth of wheat plants which included both of spring and winter types and considered whether the activity might be a sharp measure of metabolic functions or not. The interrelation between the activity and grades of the spring-sowing habit was also considered. Four typical varieties belonging to each type were sown in both fall and spring, The activity was measured by the Na-thiosulfate method in the leaf just below the terminal, every one month in the autumnal growing and every half month in the vernal growing. Moisture and dry matter contents of the plant body and other growth elements were also surveyed and discussed in relation to the activity. Main results : (1) In the case of the autumnal growing, varieties of both types showed similar changes of the activity throughout the growth, that is, somewhat high in the early stage and minimul during cold seasons. The activity was then promoted from March up to the maximum found in either April or May and decreased thereafter. When they were sown in spring, the maximum activity found in the middle of April was followed by the reduction until the middle of May. An increase was shown again in the end of the month, being followed by the decrease thereafter. (2) In autumnal growing, changes of the ratio of moisture to dry matter was fairly analogous to those of the activity. During cold seasons, high dry matter against moisture was answered by low activities. With the beginning of jointing, moisture grew larger against dry matter and the activity rose. At the plant maturation the case stood reverse. When grown in spring, they showed the activity and the ratio going nearly parallel. The maximum of both values was found in the end of April, being followed by the reduction till the minimum of the activity in May and of the ratio in June. The fall of the ratio was conspicuous in spring varieties, but gradual in winter ones since May. However the activity was circumstanced quite reverse in contrast to the ratio at those stages when the so-called "Sitzenbleiben" occurred in winter varieties. This fact indicated winter varieties with small dry matter against moisture were answered by low activity. (3) When grown in autumn, spring varieties which grew early showed higher activities than winter ones of late maturing throughout the whole course of the growth. A positive correlation between seed catalase activities and the growth duration of wheat varieties found by the author (1948) was proved again in leaf catalase activity. In vernal growing this relationship proved true only since the month of May.