Physiological responses of three pomegranate cultivars under flooded conditions

Pomegranate (Punica granatum L.) is known for its great resistance to abiotic stresses such as salinity or drought. However, its behavior under flooding − which is very common in the southeast of Spain, due mainly to the presence of heavy soils − has not yet been studied. This experiment was carried out in a greenhouse, with three of the pomegranate varieties most used in southeastern Spain: 'Mollar de Elche', 'Valenciana', and 'Wonderful'. The plants were immersed in containers of 20 liters capacity, leaving the water level three centimeters above the root zone for six days. Measurements of growth parameters, water relations, gaseous exchange parameters, chlorophyll fluorescence, organic solutes, oxidative stress, and the hormonal response were performed. The first variety that showed symptoms of stress was 'Valenciana', the one whose water relations, gaseous exchange parameters, total dry biomass, and chlorophyll fluorescence were affected most. It was also the one with the worst hormonal response. The flooding also negatively affected the growth parameters of 'Wonderful' and 'Mollar de Elche', but much less than in 'Valenciana'. From this study we can conclude that flooding tolerance of pomegranate crops depend on the cultivar. So, 'Valenciana' cultivar was the most sensitive and 'Mollar de Elche' the most tolerant.