Studies on the growth of rice tissue under submerged condition. I. The effect of 2,4-dichlorophenoxyacetic acid on excised segments of coleoptiles under submergence

Summary

The work presented deals with the fact that rice coleoptiles elongate more rapidly and more extensively under water than in air.

Coleoptile segments of rice were cultured under submerged condition as well as under floating condition. On application of 2,4-D a sharp and significant increase in growth in elongation was recorded.

At higher concentrations e. g., 100 and 10 p. p. m. the growth rate was higher in floating segments of coleoptiles. But at lower concentrations, including control, the growth rate was higher in submerged ones, which apparently indicates that the optimum concentration of 2,4-D for growth of rice coleoptile is shifted with shifting of oxygen tension. Three different mutually opposing factors namely, lowered auxin destruction under submergence, concentration of auxin in the plant tissue and lowered aerobic respiration have been stated to be responsible for growth of rice tissue under water.

At the end we offer our sincere thanks to Dr. P. K.Sen, Khaira Professor and Head of the Department of Agriculture, University of Calcutta for granting all facilities to complete this investigation.