Articles
WATER UPTAKE AND GROWTH OF CUCUMBER PLANTS (CUCUMIS SATIVUS L.) UNDER CONTROL OF DISSOLVED O2 CONCENTRATION IN HYDROPONICS
Article number
440_35
Pages
199 – 204
Language
Abstract
Dissolved O2 concentration ([O2]) in nutrient solution was controlled at 0.01, 0.10 and 0.20 mM with accuracy of ±0.005 mM in a newly developed hydroponic system, and the effects of [O2] on water uptake and growth of cucumber plants (Cucumis sativus L.) were analyzed.
For evaluating water uptake rate under the control of [O2], water flux at the stem base was measured on-line with ±5% in accuracy, 1 mg s-1 in resolution and 1 min in time constant by heat flux control (HFC) method.
Water uptake rate was drastically increased by lighting to the plant at each [O2], and water uptake per day was depressed in proportion to decrease in [O2]. In the plants grown for 10 days, leaf area, fresh weight and dry weight of leaves decreased at lower [O2], while stem length and number of leaves were scarcely affected.
These facts suggest that membrane permeability of root cells reduces at lower [O2] through respiration-dependent processes, and growth is inhibited through leaf turgor loss caused by the depressed water uptake of roots in O2-deficient nutrient solution in hydroponics.
For evaluating water uptake rate under the control of [O2], water flux at the stem base was measured on-line with ±5% in accuracy, 1 mg s-1 in resolution and 1 min in time constant by heat flux control (HFC) method.
Water uptake rate was drastically increased by lighting to the plant at each [O2], and water uptake per day was depressed in proportion to decrease in [O2]. In the plants grown for 10 days, leaf area, fresh weight and dry weight of leaves decreased at lower [O2], while stem length and number of leaves were scarcely affected.
These facts suggest that membrane permeability of root cells reduces at lower [O2] through respiration-dependent processes, and growth is inhibited through leaf turgor loss caused by the depressed water uptake of roots in O2-deficient nutrient solution in hydroponics.
Authors
S. Yoshida, M. Kitano, H. Eguchi
Keywords
cucumber, Cucumis sativus L., dissolved O2 control, HFC methods, hydroponics, plant growth, water uptake rate
Online Articles (117)