Physiological and biochemical changes of common bermudagrass (Cynodon dactylon [L.] Pers.) under combined salinity and deficit irrigation stresses.

Abstract: Experiments were conducted to evaluate the effects of combined water salinity and deficit irrigation on common bermudagrass in order to address the shortage of water resources and increasing water and soil salinity in arid and semi-arid zones. This study was carried out under greenhouse conditions in a completely randomized design with factorial arrangements. Treatments included 4 water salinity levels (0.5, 3, 6 and 9dSm−1) and 4 deficit irrigation regimes (2, 4, 6 and 8day intervals). Results indicated a rise in ion leakage, soluble sugars and proline concentrations; and a drop in leaf relative water content (RWC), leaf chlorophyll content and photosynthetic rate with increasing levels of both stresses. Antioxidant enzymes, superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7) and ascorbate peroxidase (APX, EC 1.11.1.11) showed higher activity under moderate drought or salinity conditions. However, these enzyme levels dropped at higher levels of these two stresses. Based on the results of the present study, common bermudagrass could be grown under moderate combined water and salinity stresses without considerable damage to plants at the physiological and/or biochemical level. This is the first report of applying combined water and salinity stresses to an important turfgrass species. Further studies are needed to evaluate the effects of these stresses on characteristics of bermudagrass at the molecular and ultrastructural levels. [Copyright &y& Elsevier]