EFFECT OF 2,4-DICHLOROPHENOXYACETIC ACID ON MERISTEMATIC TISSUES OF CORN

Abstract

The appln. of 2,4-D to corn plants at the time of the first microscopic evidence of tassel initiation in the growing points, caused severe inhibition of tassel development. Treatments with 2,4-D 6 and 11 days later caused much less inhibitory effect. Applns. of 2,4-D at the time of tassel emergence resulted in the inhibition of developing ear shoots. Applns. of 2,4-D 1-4 days before silk emergence caused severe inhibition of seed set on the developing ear. Applns. after silking had no effect on ear development. The effects of 2,4-D in reducing the development of tassels, in suppressing the development of ear shoots and in inhibiting seed set on developing ears, seemed to show a degree of similarity with respect to the kind of cells affected. Considering the three types of injury together, it seems probable that the inhibitory effect occurs during specific meristematic differentiations. The susceptible period is apparently relatively short for each of the 3 growth stages studied.