ABSORPTION OF HERBICIDES BY ROOTS

Crafts , A. S., and S. Yamaguchi . (U. California, Davis.) Absorption of herbicides by roots. Amer. Jour. Bot. 47(4): 248—255. Illus. 1960.—Many herbicides are used through soil. When 2,4-D*² was applied to culture-solution barley, bean, cotton, and Zebrina plants, there was evidence that the herbicide is held at high concentration by the roots. Very little of the labeled compound moved into the tops of barley, Zebrina and bean; a fair quantity was found in cotton foliage. Barley seedlings allowed to absorb 2,4-D*, ATA*, MH*, urea*, monuron*, dalapon*, simazin*, P³² and IAA* showed interesting differences. All chemicals were highly sorbed by roots, 2,4-D* was moved to tops in least amount, urea was next; the other seven were moved in larger quantities. ATA*, MH*, IAA*, P³², and dalapon* seemed readily phloem mobile; monuron* and simazin* seemed limited to xylem movement. Results are discussed in relation to the mechanism of root uptake.