Growth responses and root porosity of rice in relation to temperature, light intensity and aeration

Abstract

Experiments were conducted under which rice plants were grown under three energy input levels (temperature and light) and two solution-oxygen concentrations. The rice variety was Colusa. Increasing the energy input increased total top growth. There was no significant effect of solution-oxygen concentration on top growth. The highest number of tillers developed under medium energy input followed by high energy input and the least under low energy input. There was a trend towards more tiller production under low oxygen conditions as compared to high oxygen. Decreasing the oxygen supply increased the dry weight production of roots under the two higher energy input levels, but had no significant effect under the low energy input. The highest amount of root growth occurred under high and medium energy input and least under lower energy input. Increasing the energy input increased the percent root porosity, but the oxygen level had no significant effect on root porosity. None of the treatments had a significant effect on nitrogen concentration in the tops. The amount of water necessary per unit dry matter production had a trend towards increase with increased energy input level and also significantly higher under low oxygen as compared to high oxygen conditions.