Abstract
In the previous paper the author reported on the growth of various crops in soil of optimum, high and low moisture, and it was found that Italian rye grass was more resistant to high moisture than Rye and Oat. It is known that absorption of water by root from the soil solution and resistance of plant to freezing and to desiccation are partly able to be determined by osmosis. The results of the comparative study on limiting concentration causing plasmolysis of root-cell and on the osmotic concentration of root-sap by means of freezing point method were reported in this paper. Italian rye grass, Rye and Oat were used as materials, and those plants were cultured in three plots classified on the basis of their moisture contents of soil. The results were as follows: (1) The limiting concentrations of plasmolysis of root-cells decreased with the progress of day from february to march; it increased in february, the coldest period of the year, and decreased very rapidly. (2) The limiting concentration of Italian rye grass was lower than that of the others. (3) When these crops grew in plot of high moisture, their osmotic concentrations were lower than those of the crops in the others. (4) A simillar tendency was observed also in experiment carried out by means of freezing point method. (5) Water absorption of various crops was decreased at low soil temperature, especially, this phenomenon was observed in the crops growing in soil of high moisture. (6) The osmotic concentration of Italian rye grass was lower as compared with that of the other crops growing in soil of high moisture, but the amount of water absorpted by Italian rye grass was greater than those by the other. (7) The moisture contents of these crops were less in soil of high moisture than in soil of optimal and low moisture. Judging from above observation, it seems that the amount of bound water increases in these crops growing in soil of optimal and low moisture.
