Research Information System
South African Journal of Botany, vol.178, pp.382-389, 2025 (SCI-Expanded)
Drought tolerance of OHxF 333 (Pyrus communis L.), the wild pear clone (P. elaeagrifolia Pall.) and East Malling Quince A (QA) (Cydonia oblonga Mill.) was assessed by morphological, physiological and biochemical responses of in vitro microshoots. The microshoots were cultured on Murashige and Skoog (MS) medium with or without D-mannitol containing 1.0 mg L−1 BA (benzyladenine), and 0.5 mg L−1 GA3 (gibberellic acid), 3 % sucrose and 0.7 % agar. The osmotic potential of the media was adjusted to -0.8 (mild stress), -1.1, -1.3 (moderate stress) and -1.6 MPa (severe stress) using D-mannitol at doses of 0, 200, 300 and 350 mM, respectively. After six weeks in culture, the percentages of survival and proliferation and shoot growth parameters of microshoots were determined. Total chlorophyll and proline contents, hydrogen peroxide (H2O2) and antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were evaluated. Mineral element concentrations such as phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) sodium (Na), iron (Fe), zinc (Zn) and manganese (Mn) were determined. Under severe drought stress induced by 350 mM D-mannitol, only the wild pear (P. elaeagrifolia) microshoots continued to grow and proliferate. The percentage decrease in the number of shoots and the lowest change (%) in shoot length and thickness under severe stress was determined in the wild pear clone. Proline content, SOD and APX activity increased with salt stress whereas P, K, Ca, Mg, Zn and Mn and total chlorophyll content were decreased with 350 mM D-mannitol. The results of the study revealed that the wild pear clone and OH×F 333 were more tolerant to drought stress compared to QA demonstrating the potential of wild pear clone as a rootstock for pears under drought stress conditions.