Effects of drought and salt stresses on growth, stomatal conductance, leaf water and osmotic potentials of melon genotypes (Cucumis melo L.)

Drought and salt stress is the major constrains to crop productivity. However, resistant genotypes improve their physiological mechanisms to cope with these stresses. In this study, we have investigated the influences of drought and salt stress on dry weight, leaf osmotic potential, leaf water potential, leaf temperature and stomatal conductance in sensitive and resistant melon genotypes. Four melon genotypes (sensitive, CU 40 and CU 252; resistant CU 196 and CU 159) were grown in a mixture of peat:perlite of 2:1 ratio in growth chamber. Salt and drought stresses were observed in 30 days old melon plants. In order to perform salinity stress, 200 mM NaCI was used. The drought stress was achieved by decreasing irrigation water gradually and finally irrigation was completely stopped. The plants were subjected to the salt and drought stresses for 12 days. At the end of the experiment; shoot dry weight, osmotic potential, leaf water potential and stomatal conductance were lower in salt and drought-sensitive genotypes (CU 40 and CU 252) than the resistant ones (CU 159 and CU 196). The leaf temperature was increased under stress conditions in melon genotypes. The results showed that resistant melon genotypes have more efficient stress protection mechanisms to survive under salinity and drought conditions.