Drought stress mitigation with humic acid in two Cucumis melo L. genotypes differ in their drought tolerance

ABSTRACT Different responses of two melon (Cucumis melo L.) genotypes (Şemame, drought and salt-tolerant and Ananas, drought and salt-sensitive) to drought stress with or without humic acid (HA) treatment were studied. The experiment was carried out under greenhouse conditions. The experimental design was two factorial randomized block with 4 replicates. HA treatment increased the shoot fresh and dry weights and leaf area of both genotypes under drought stress. HA stimulated accumulation of K and Ca ions, chlorophyll (SPAD value) and antioxidant enzyme activity (superoxide dismutase-SOD, catalase-CAT and glutathione reductase-GR) in both genotypes. This effect was more clear in the Şemame genotype than in Ananas.As a result, HA treatment has been proved to influence the ability of melon genotypes to cope with drought stress and to increase their tolerance.