水稲苗の活着に及ぼす低温と水分ストレスの影響

抄録

Interaction of low temperature and water stress on the growth of transplanted rice seedlings was investigated. The results were as follows: 1. Root decapitation inhibited the growth of transplanted rice seedlings through water stress, and the application of antitranspirant or leaf pruning was effective to aleviate the growth inhibition (Table 1). 2. Spindly seedlings due to high temperature and low light intensity exhibited a poor growth as compared with vigorous one grown outdoors. This disparity was more conspicuous at low temperature than at normal one, and magnified by water stress put on the seedlings by ventilation. Rooting of spindly seedlings was completely inhibited by water stress due to ventilation (Table 2). 3. High osmotic pressure of medium solution which presumably put a water stress on the seedlings obviously inhibited their rooting. The same was observed in the elongation of seminal root of germinated seeds. The above inhibitory effect of high osmotic pressure on the rooting and root elongation was also more conspicuous at low temperature than at normal one (Fig. 1, 2, 3). The results obtained here showed that a much attention should be paid to avoid water stress on rice seedlings transplanted under low temperature.