Intercellular Void Space Effects On Kentucky Bluegrass Traffic Tolerance

Athletic field safety is a top concern of field managers and athletic directors across all sports. Increased field usage on fields with traffic-sensitive cultivars results in reduced turf cover and therefore decreased field safety. Kentucky bluegrass (Poa pratensis L., KBG) is the most widely used cool-season turfgrass on athletic fields due to its dense turf canopy. While most KBG cultivars have strong recuperative potential, significant cultivar differences in ability to withstand athletic field traffic exist. This study was conducted to determine whether leaf epidermal cell sizes predict differences in KBG cultivar traffic tolerance. Upper epidermal cell size, lower epidermal cell size, and intercellular void space (IVS) were measured on three traffic-tolerant and three traffic-sensitive KBG cultivars from the 2011 National Turfgrass Evaluation Program KBG trial, arranged in a randomized complete block design with three replications. Transverse sections of leaf tissue were fixed in an acid/alcohol solution and embedded with paraffin prior to sectioning for imaging by light microscopy. Cell size was determined by counting cells per unit area from light microscopy images. Leaf upper and lower epidermal cell size was not a predictor of traffic tolerance. Differences were measured in IVS at the cultivar level and at the traffic-sensitive vs. traffic-tolerant grouping contrast level. Traffic-tolerant cultivars exhibited larger IVS (2823 mu m(2)) than traffic-sensitive cultivars (1112 mu m(2)). Further investigation of these leaf anatomy size theories in relation to athletic traffic tolerance should be conducted on more cultivars, including recently released commercially available genotypes.