THE EFFECT OF SOIL WATER DEFICIT ON INTERNAL WATER RELATIONS OF KIWIFRUIT

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.

III International Symposium on Kiwifruit

K. Chartzoulakis, I. Therios, B. Noitsakis

Water potential, relative water content, osmotic adjustment, modulus of elasticity

https://doi.org/10.17660/ActaHortic.1997.444.47