Effects of CaCO₃-derived Ca doses applied at different pH levels under in vitro conditions on the morphophysiological and biochemical parameters of selected standard grape cultivars and rootstocks

In this thesis study, it was aimed to determine the morphological, physiological, and biochemical responses of some standard grape cultivars and grapevine rootstocks to CaCO₃-Ca doses applied at different pH levels under in vitro conditions. Banazkara, Köhnü, and Öküzgözü grape cultivars, together with 41B, 5BB, and 1103P grapevine rootstocks, were used as plant materials. The experiment was conducted in media adjusted to pH 5.8, representing standard in vitro culture conditions, and pH 8.0, representing calcareous-alkaline conditions. Control (0), 16, 80, 320, and 800 mg L⁻¹ CaCO₃-Ca doses were applied. The effects of the treatments were evaluated in terms of plant survival rate, rooting, plant growth, chlorosis severity, SPAD value, chlorophyll content, active and total iron contents, Fe-reductase activity, and proline content. The findings obtained from the study showed that increasing CaCO₃-Ca doses markedly restricted plant growth, particularly under pH 8.0 conditions. Among the grape cultivars, Banazkara exhibited a more tolerant response to the treatments, whereas Köhnü was found to be more sensitive, and Öküzgözü displayed variable responses. In grapevine rootstocks, it was determined that tolerance could not be explained by a single parameter and that multiple physiological and biochemical indicators should be evaluated together. In conclusion, this study has the potential to contribute to the identification of genotypes adapted to calcareous-alkaline conditions, to rootstock selection, and to the development of physiological selection criteria that may be used in breeding studies.