Relatin between Rate of Transpiration and Rate of Absorption of Water in Seedlings of Cryptmeria japonica Exposed to Artificial Wind

1. In order to study the influence of wind on the rates of absorption and transpiration of seedlings of sugi (Cryptomeria japonica D. DON), simultaneous measurements of the two processes were carried out, using water-cultured plants. 2. When the seedlings were exposed to artificial wind, transpiration rate suddenly increased and then decreased gradually, while the rates of absorbtion increased gradually and exceeded the rate of transpiration after 2 or 2.5 hours of exposure to wind. The lag of the change of absorption behind transpiration probably results from the fact that the rate of transpiration responds immediately to change in enviromental conditions but absorption does not increase until the effect of saturation deficit caused in the leaves by transpiration is transmitted to the roots. 3. When seedlings without roots were exposed to wind, traspiration showed the similar change as that of the intact seedlings, but the change in the rate of absorption was not similar to the latter. It resembled rather to the change of transpiration, though the change in the rates of absorption lagged behind transpiration. It suggests that absorption lag was chiefly caused by root resistance, but resistance in leaves and stems was not negligible