Soil-Water-Plant Relations Utilizing Divided Root Systems of Soybean.

摘要

The root systems of soybean plants were divided between two sides when grown in a sandy clay loam soil in growth chambers. Soil moisture was measured either by a gravimetric imbalance or by an electrical resistance technique. Thermocouple psychrometers were used to measure water potentials of the lower stem. Psychrometric estimates of leaf and soil water potentials were obtained. Plants that have wilted and recovered turgor were found to transpire more slowly than before,primarily because of reduced stomatal aperture. The magnitude of the effect is related to the severity of wilting. Root resistance is less at higher flow rates,but stem water potentials show little change with changes in flow rates. That part of a root system in soil from which additional water is withheld will reduce the water in that soil to a low level though the water around the other roots is maintained at a high level.