The Effect of Localized Pressure on the Growth of the Maize Radicle

Abstract

When radicles of Zea mays (L.) are compressed they elongate less rapidly. In this experiment different regions of the radicle were compressed to localize the effects of the stress. Compressing the apex at 1 kg/sq cm reduced growth much more than compressing a length of fully enlarged tissue. The most striking change in compressed apices was a reduction in the rate of elongation, and this is attributed chiefly to a change in the shape assumed by cells enlarging under stress. A mechanical load of 3 kg/sq cm caused browning and loss of turgor when applied to fully enlarged tissue, but this did not occur when the tissue enlarged and matured under stress.