Abstract
The influence of osmotic potential and water potential on the leaf expansion and leaf weight were studied with a Japanese native tobacco variety ‘Shiroenshu’grown in irrigated or non-irrigated plots on volcanic ash soil. Water status in leaf, chemical component and yield of irrigated and non-irrigated tobacco were also examined. Leaf area and leaf weight of non-irrigated tobacco were smaller than those of irrigated tobacco. The decrease in leaf area and leaf weight were closely correlated with the depression of pressure potential (turgor pressure) of leaves. The rate of water loss at room temperature of detouched leaves of middle position in the irrigated tobacco was faster than that of the non-irrigated one. The rate of water loss in upper leaves was slower than that in lower ones.
Chlorophyll content in the irrigated tobacco was maintained longer than those in non-irrigated one. It was supposed that the cells of the upper leaves of the irrigated tobacco were kept younger than that of the non-irrigated tobacco. Yield and quality of the irrigated tobacco were higher than those of the non-irrigated one.
