Annals of Botany 52: 839-847, 1983
© 1983 Annals of Botany Company
RESEARCH-ARTICLE |
Studies of Water Uptake from Multiple Sources
3M Science Research Laboratories of Central Research 3M Centre, Building 201-2w, St Paul, Minnesota, 55144, USA
Accepted: 20 April 1983
Water uptake in systems consisting of a potted plant and two embedded reservoirs, which had been fitted with microporous bottoms, were monitored daily over test intervals that ranged from 1 to 3 years. When both reservoirs contained aqueous solutions of the same chemical composition, plants took water from the alternate sources without bias, but when one reservoir contained tap water and the other a strong aqueous nutrient solution, an initially fluctuating bias developed. Eventually the system re-stabilized at an equilibrium state in which total uptake of water (in 1 day–1) to nutrient salt (in g day–1) was about 16 to 1 independent of the concentration in the nutrient solution. This equilibrium ratio was altered sharply whenever the plant was damaged severely, or whenever the quality of the water in one of the reservoirs was impaired by addition of a toxicant. The equilibrium state was re-established within 6 months following plant damage, and within a few weeks following elimination of the toxicant. The above results demonstrate that multireservoir systems, which can be assembled easily from inexpensive components, provide a reliable means for studying water uptake by a single plant from two or more independent sources, and that these systems are very sensitive to changes that affect the physiology of the plant.
water uptake, selective uptake, potometry, membranes, permeability, root growth, split-root growth, hydroponic