Seasonal patterns of water relationships, photosynthetic pigments and morphology of Actinidia deliciosa plants of the Hayward and Tomuri cultivars

Abstract

Plant water relationships, photosynthetic pigments, osmotic solutes and several morphological parameters were measured on leaves of 6-yr-old pistillate (Hayward) and 6-yr-old staminate (Tomuri) cultivars of kiwifruit grown under Mediterranean climate conditions, in order to evaluate physiological differences between them, and whether a good discriminatory parameter can be obtained between rooted cuttings. The staminate cultivar had higher leaf turgor and losses turgor at lower leaf-water potential than the pistillate cultivar. This was related to the lower osmotic potential at full turgor in Tomuri compared with Hayward, together with the elastic properties of leaf tissue. Seasonal patterns of water potential components, cuticular water loss, proline, soluble sugars, photosynthetic pigments, cutin, turgid weight/dry weight ratio and specific leaf weight were all similar in both cultivars. whereas the hemicellulose/cellulose ratio differed. Thus, leaf-tissue elasticity is important in determining the drought-resistance strategy of both cultivars, and the chemical composition of the cell walls, which is strongly related to tissue elasticity, could provide a good discriminatory parameter. © 1994.