Waterlogging and Inundation Tolerance of C4 Turfgrasses

Relative waterlogging and inundation tolerance of five C₄ turfgrasses [Axonopus compressus (Sw.) P. Beauv.; Cynodon dactylon L. × C. transvaalensis L.; Paspalum vaginatum L.; Stenotaphrum secundatum (Walt.) Kuntze; and Zoysia matrella Willd.] were determined by growing them in pots held under different waterlogging levels. Established grasses were exposed to 4 water level treatments: 1) WLC: Control, well drained; 2) WL-5: water level maintained at 5 cm below soil surface; 3) WL0: water level maintained at soil surface; and 4) WL+5: inundation—water level maintained at 5 cm above soil surface. Following 10 weeks of waterlogging stress, there was a reduction in live shoot turf density (TD), chlororphyll fluorescence (CF), leaf dry weight (LDW), shoot length (SL), root length (RL), root area (RA), root dry weight (RDW), and root/shoot ratio (R/S). All parameters were analyzed, and thus effective in predicting waterlogging and inundation tolerance. Aerenchyma formation was observed in the roots of all species under waterlogging stress.  Waterlogging and inundation tolerance varied among the 5 turfgrass species. Under waterlogging treatments WL-5 and WL0, Axonopus compressus and Stenotaphrum secundatum were tolerant, while Paspalum vaginatum, Cynodon dactylon, and Zoysia matrella were moderately tolerant. Only Paspalum vaginatum was tolerant to inundation (WL+5). Cynodon dactylon and Zoysia matrella were moderately sensitive, and Axonopus compressus and Stenotaphrum secundatum were highly sensitive to inundation. Understanding waterlogging tolerance potential of C₄ turfgrasses could be utilized to improve turfgrass management in tropical conditions, where rootzone waterlogging occurs frequently.