Some Observations on Invertase Activity in Roots ofVicia fabaL.

Abstract

Invertase activity has been determined at intervals along primary roots of Vicia faba as they elongated from 0·5 to 8 cm. Little activity was evident in 0·5–1·0 cm long primaries but in those 2–8 cm in length the main peak of enzyme activity was associated with the region of cell elongation. Changes took place in the pattern of invertase activity along the primary roots as they lengthened and these changes have been correlated with fluctuations in both the rate of root elongation and the supply of sucrose to the root from the cotyledons. The presence of a root cap did not increase the activity of this enzyme in the apical 1 mm of these roots. Invertase activity was higher in lateral root primordia than in most parts of the primary root basal to the meristem, presumably because of the presence of sucrose in the adjacent cavity in the cortex of the primary root. The peaks of invertase activity found basal to the region of cell elongation in 3–8 cm long primary roots probably resulted from the development of root pnmordia in these parts of the root.