Gibberellic Days after Spraying

photosynthesis (1). Total radioactivity fixed per leaf was unchanged by the two-hour treatment with gibberellic acid; typical results are shown in table I. Similar results were also obtained in one experiment with Chlorella pyrenoidosa. Examination of autoradiograms of the chromatograms of extracts from the oats, barley, and peas showed no significant differences in the distribution of C'4 among the soluble products within any one species. Experiments were also performed 2 days after one-week-old oats, and 3, 6, and 9 days after 9-dayold peas had been sprayed with gibberellic acid. In these experiments the leaves were put in vials containing water in the photosynthesis chamber for 15 minutes and then immediately exposed to C1402 for 20 minutes. There was no significant difference in amount of C1402 fixation or in distribution of C14 among the products of photosynthesis even though the plants had shown a typical response to gibberellic acid (table II).