Catalase Activity and Respiration in the Leaves of Growing Barley^

There has been some diiïereiice of opinion as to whether there is an association between catalase activity and respiration. In 1910 Appleman (1) ^ noted a correlation between the two in the potato tuber and later (2) observed the same thing in potato tubers manipulated in various ways to modify respiration and in stem and seed ends of the same tuber. He found a similar correlation in stored sweet corn (8)^ and concluded that catalase activity is a fair index of the comparative intensity of respiration in the tissues of sweet corn and potato tubers. Morinaga (11), from studies of rice seedlings grown under differing conditions of aeration, concluded that there is a close positive connection between the two {)henomena, and Bürge (4) and Bürge and Bürge (5) are convinced, from studies of a number of organisms, that catalase activity is definitely associated with metabolism and with respiration in particular. Others, however, have not obtained such convincing results. Crocker and Harrington (6) found a positive correlation between respiration and catalase activity in seeds of Johnson grass (Sorghum halepensis (L.) Pers.) and probably in those of Avena fatua L. but not in Amaran thus seeds. Rhine (IS), working with germinating seeds, concluded that catalase activity is a measure of metabolism only when there is no rapid change in respiration. Lantz (10) did not find a close correlation between catalase activity and respiration in germinating corn of different chemical composition (high and low oil, high and low protein). The writer has demonstrated widely different degrees of catalase activity in different parts of the same barley (Hordeum distichon) plant.^ The relationship between catalase activity and respiration in leaves of different age is shown in this paper.