EFFECTS OF WATER STRESS ON PLANT GROWTH AND PHYSIOLOGICAL CHARACTERISTICS OF SOME GRAPE VARIETIES

The objective of the present study is to investigate the physiological, morphological and structural changes induced by water deficit on four different table grape cultivars that are commonly cultivated in the Mediterranean region. One-year-old vine (Vitis vinifera L.), cultivars 'Crimson Seedless', 'Superior Seedless', 'Razaki' and 'Horoz Karasi' grafted onto 1103 P rootstock were grown in a greenhouse in a soil/farmyard manure/sand/turf mixture (2:1:1:0.5) in pots; and subjected to water stress for 40 days. A 60% limitation of the available water caused total leaf area and dry weight decrease as well as negative impact on growth in all cultivars. As a result of this application, a distinctive decrease in root growth was observed in the Crimson Seedless, Superior Seedless and Razaki cultivars, in comparison with the control. While there was no significant change in grade of leaf thickness, leaf tissue density, or leaf succulence during water stress application, increases in leaf K, Fe, Cu, and Zn contents, chlorophyll content, and leaf electrolyte leakage were observed. Significant differences were seen among the grape cultivars in terms of adaptation to aridity conditions. Generally, the most sensitive grape cultivar in terms of tolerance to water stress was Superior Seedless, whereas the cultivar that can optimally adapt to conditions of higher aridity was Horoz Karasi.