Short-term growth response of deep-water rice to submergence and ethylene

Abstract

An angular transducer has been used to measure the short-term growth response in submerged and ethylene-treated deep-water rice plants. The lag time between the start of submergence and the onset of the response is 200 min, indicating that growth-related biosynthetic processes take place before internodal elongation starts. The level of endogenous ethylene in the internodes rises steeply prior to the onset of growth, which is further support for the hypothesis that accumulation of ethylene is a prerequisite for the growth response in submerged plants. The growth rate plotted against time shows a first peak after 6 h followed by a decrease and subsequent increase in the growth rate. Similar growth curves have also been found in other plants after application of indoleacetic acid and gibberellic acid. Partial adaptation of plants to growth hormones may be the reason for biphasic growth-response curves.