抄録
The present work was planned to obtain further information as to the effect of salinity on rice plants, particularly from the view point of osmotic adaptability of rice plants to saline solution, using a variety "Eiko" as material. The plants were grown in culture soltion in a green house for about 3 weeks. Then they were subjected to hypertonic solutions containing 0.1, 0.2, and 0.3 M sodium choride, respectively. The osmotic pressures of plant saps obtained from rice plants and of culture solutions were measured by cryoscopic method. The amount of choride in expressed saps of rice plants was determined by Volhard's method. When the rice plants were treated with saline solution, the rolling of leaves and the browning of leaf-tips were recognized. At the same time the water contents in salt-treated rice plants decreased remarkably. On the other hand, the increase of the amounts of chloride in the experessed sap of rice plants treated with saline solution was recognized. Simultaneously this increase caused in turn the increase of osmotic pressure of rice plants. It seems quite clear from these facts, therefore, that the rice plants have high adility to adjust their osmotic pressures according to that of the surrounding solution. When the experimental plants were transferred from the saline solution to basic solution, the water and chloride contents and osmotic pressure of the expressed sap recovered to each original level which was observed in the basic nutrient solution, whithin a limit of saline concentrations used.
