Growth, physiological, and anatomical responses of creeping bentgrass cultivars to different depths of waterlogging

Oxygen deficiency is one of the primary root stresses in waterlogged or flooded soils. The objective of this experiment was to identify growth, physiological, and anatomical traits of creeping bentgrass (Agrostis stolonifera L.) associated with tolerance to different depths of waterlogging (WL). Five cultivars (L-93, A-4, G-6, Penncross, and Pennlinks) were subjected to the four WL treatments for 21 d: (i) drained control; (ii) water level at 15 cm (WL-15); (iii) water at 5 cm (WL-5); and (iv) water at 1 cm (WL-1) below the soil surface, respectively. Waterlogging reduced turf quality (TQ), root dry weight (RDW), root water soluble carbohydrate content (RWSC), and root soluble protein content (RPRO), while no significant reductions in RWSC, RDW, or RPRO were observed among three depths of WL. Turf quality and chlorophyll content (Chl) decreased with increasing water level from 15 to 1 cm. At WL-1, Chl, RDW, RWSC, and RPRO were reduced 27, 20, 44, and 22%, respectively, compared In the control. Cultivar differences in TQ, RDW, shoot water soluble carbohydrate content (SWSC), and RPRO were observed under WL. G-6 and L-93 had better quality than A-4, Penncross, and Pennlinks under WL conditions. The formation of aerenchyma was enhanced at WL-15 and WL-5. Mitochondrial swelling occurred under WL, particularly at WL-1. The results suggest that even partial WL (WL-15 and WL-5) could substantially affect turfgrass growth and physiological activities and cultivar variation in WL tolerance could potentially be used for enhancing breeding programs.