RESPONSE OF in vitro CULTIVATED EGGPLANT (Solanum melongena L.) TO SALT AND DROUGHT STRESS

Abstract

Salinity and drought are some of the major abiotic stresses that adversely affect eggplant productivity and quality. The response of in vitro cultivated plants of three eggplant cultivars - Lagra Negra (LN), China-A2 (CH) and Black Beauty (BB) to sodium chloride (NaCl) and polyethylene glycol (PEG8000) induced stress was studied. The Murashige and Skoog, 1962 nutrient medium (MS + 1% sucrose and 0.8% agar) supplemented with NaCl (0; 50; 100; 150 and 200 mM) or PEG (0; 3; 8 and 10%) was used. The survival rate, percentage of rooted plants, plant height and root length were recorded after three weeks of cultivation. The addition of 50 mM NaCl to the MS culture medium influenced positively the plants growth, development and rooting. The survival percentage significantly decreased while increasing salt concentration in the culture medium, especialy at 100 mM NaCl. Concentration of 150 mM NaCl was toxic for the plants of all studied cultivars. The in vitro response of eggplant to drought stress was tested as well. The percentage of surviving plants also decreased while increasing PEG concentration in the culture medium. The appropriate concentrations of the abiotic agent (100 mM NaCl for salinity and 8% PEG for drought) for in vitro selection of tolerant eggplant plants were established. Salinity and drought due to NaCl and PEG respectively resulted in higher and more pronounced levels of proline in the cultivar LN plants, probably due to their better adaptation to abiotic stress.