Interaction Effects of Salinity and Mowing on Performance and Physiology of Bermudagrass Cultivars

The effects of mowing management on salinity tolerance are not well understood. These effects were studied on turf quality, clipping yield, root mass, canopy photosynthetic rate (Pn), total nonstructure carbohydrate content (TNC), shoot reducing sugar content (RSC), and K+ and Na+ contents in shoots and roots of Tifgreen, Tifdwarf, and Tifway bermudagrass [Cynodon dactylon (L.) Pers.] cultivars using a hydroponic system. Increasing salinity resulted in a significant (p < 0.05) reduction in turf quality. Canopy photosynthetic rate values in Tifgreen were the highest (9.92, 12.98, and 18.91 mu mol CO2 m(-2) s(-1) at 15, 30, and 45 mm mowing heights respectively) compared with Tifdwarf and Tifway at 20 dS m(-1). Tifgreen achieved 22, 20, 21, and 32% more clipping yield than Tifway at control and 8, 16, and 20 dS m(-1) salinity levels respectively under the highest mowing level. At the highest mowing height, the increase in Tifgreen, Tifdwarf, and Tifway root mass was 33, 40, and 31%, respectively, as salinity increased from control to 20 dS m(-1). Total nonstructure carbohydrate content decreased by 36, 21, and 18% in Tifgreen while RSC increased by 35, 34, and 32% at 15, 30, and 45 mm mowing heights, respectively, as salinity increased from control to 20 dS m(-1). Bermudagrass had the highest selectivity of K+ over Na+ when maintained at 45 mm mowing height. Tifgreen showed significantly (p < 0.05) higher salinity tolerance compared to other tested cultivars, and the capability of bermudagrass cultivars to survive salinity stress can be enhanced by increasing mowing height.