THE RELATION BETWEEN CATALASE ACTIVITY AND VIGOR IN INBRED STRAINS AND CROSSES OF CORN SEEDLINGS

Abstract

The wide distribution of catalase in the plant and animal kingdoms led Loew (I90I) to assume that it had some definite function and to suggest that it might be associated with the respiratory processes. These processes have to do with energy release which in turn is associated with protoplasmic activity and possibly rate of growth. The rate of growth may be increased by the addition of nitrogen as may also the rate of catalase activity of apple leaves. The latter was demonstrated by Heinicke (I923) who found that the addition of sodium nitrate to a sod soil in which apple trees were growing was accompanied by an increase in the catalase activity of the leaves. The relative catalase activity was used as a basis for a viability test of various varieties of lettuce seed by Davis (I926). The test depended upon a retention or a reduction of the catalase of soaked seed as compared with that of dry seed of the same sample. Any considerable reduction in catalase was taken to indicate poorer quality of seed. In the animal kingdom Burge and Burge (I92I) found that catalase activity paralleled development in potato bugs and mice. Low oxidation in the newly born is attributed to the low catalase content while the intense metabolism characteristic of youth and adult life is attributed to high catalase content. In these determinations Burge and Burge macerated the whole eggs, larvae, pupae, and adults of potato bugs while the mice were skinned and all tissue except the skin used. This association of catalase activity with viability of seed and an increased rate of growth is not always present, as some workers have pointed out, but it leads to the suggestion that there may be a parallel between the intensity of catalase activity and the vigor of seedlings. In view of this suggestion inbred strains of corn were studied in the hope of being able to determine the vigor of a strain while in the seedling stage. The seed were from inbred strains and from crosses between them, the vigor of which, as measured by the total yield of dry matter expressed as a percentage of the total yield of the commercial stock and yield of grain, had been determined in field tests. In the present study only two partial measures of vigor were taken, each being considered independently. The first is the relative fresh weight of the tops of the seedlings and the second is the dry weight of the mature offspring of the inbred strains expressed as a percentage of the dry weight of the commercial stock from which the inbred 696