ISHS Acta Horticulturae 444: III International Symposium on Kiwifruit
THE EFFECT OF SOIL WATER DEFICIT ON INTERNAL WATER RELATIONS OF KIWIFRUIT |
| Authors: | K. Chartzoulakis, I. Therios, B. Noitsakis |
| Keywords: | Water potential, relative water content, osmotic adjustment, modulus of elasticity |
| Abstract:
The effect of soil water deficit on internal water relations of one year-old kiwi fruit (Actinidia deliciosa, cv Hayward) plants, grown in pots under controlled conditions were investigated. Water stress was imposed by irrigating the plants with 100% and 40% of water needed to reach pot capacity. Midday leaf water potential (  w) under increasing water stress declined from -1.2 MPa (control) to -2.0 MPa (severe stress). Pressure-volume analysis of plants grown under severe stress showed partial turgor maintenance as a result of incomplete osmotic adjustment, - the reduction in solute potential did not keep pace with the reduction in leaf water potential and cell wall elasticity.
The critical value of w for stomatal closure was -1.0 MPa for well watered plants, while in water-stressed plants stomatal conductance remained at low values (0.1–0.2 cm s-1) throughout the day.
Water-stressed kiwifruit plants exhibited increased resistance to water flow in the soil-plant-atmosphere system, resulting in lower relative water content (RWC) in relation to well-watered plants.
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