大気湿度が水稲の生育ならびに生理に及ぼす影響 : 第5報 水稲葉の老化に及ぼす影響

抄録

The present study examined the influence of humidity on the senescence in rice plant leaves. 1. Plants were grown for 11 days under 75% humidity with 12/12 hr; light/dark cycle, then grown at 60% or 90% humidity. Decrease in chlorophyll content of the third leaf in low humidity was faster than in high humidity, suggesting that leaf senescence progressed in low humidity more rapidly than in high humidity. 2. Water content was lower for plants grown in low humidity than those grown in high humidity. The decrease of water content was followed by the decrease of chlorophyll content. 3. High humidity increased the leaf area and accelerated the leaf emergence. 4. The products of photosynthesis in the third leaf were necessary for yong leaf emergence. The more the translocated materials from the third leaf, the faster the senescence of it. These results suggested that low humidity induced the decrease of water content, which stimulated the loss of chlorophyll (leaf senescence), and high humidity promoted the growth, which results in the delay of the third leaf senescence.