Morpho-Physiological Responses of Some Iris Cultivars under Drought and Salinity Stresses

The effects of drought and salinity stresses on morpho-physiological characteristics of three Iris (Iris spp.) cultivars ('Purple Blue Magic', 'White Madonna' and 'Blue Deep River') were investigated. Drought stress experiment included three drought levels (60, 75, and 90% of field capacity), and the salinity stress experiment included four concentration of NaCl (0, 50, 100 and 150 mM). Different drought and salt treatments had significant effects on the morphological characteristics (leaf surface, main root diameter, number of branched roots and corm dry weight) and the physiological characteristics (Relative Water Content= RWC, Carotenoid, Lipid Peroxidation= MDA, and Electrolyte Leakage= EL) of the three iris cultivars. The best vegetative growth characteristics and physiological conditions were recorded under the control treatments [most favorable moisture conditions (90% FC) and without using salt in irrigation water] and the poorest were under the most severe stress conditions (60% FC and 150 mM NaCl in irrigation water). With increasing drought stress in 60% FC level and increasing NaCl salt treatments in 100 and 150 mM, no flower appeared in the 'Madonna' and 'Blue Magic' cultivar, respectively. In this aspect, only 'Deep River' cultivar could reach flowering phase and complete life cycle in both drought and salinity stresses. We concluded that the process of flowering in some iris cultivars were sensitive to drought stress and salinity. However, by selection, resistant or tolerant cultivars or genotypes could be identified and promoted under these abiotic stress conditions.