Differential Leaf Cuticular Wax Responses to Cold Acclimation in Annual Bluegrass (Poa annua L.) and Creeping Bentgrass (Agrostis stolonifera L.)

Abstract

Winterkill is a major challenge on golf course putting greens in climates that support cool-season turfgrass species, including annual bluegrass (Poa annua) and creeping bentgrass (Agrostis stolonifera). The cuticle is a critical protective outer layer of above-ground plant organs, but its role in the winter resistance of cool-season grasses is not well understood. An enhanced understanding of cuticle-related mechanisms during cold acclimation and overwintering could reveal novel management or breeding strategies to promote turfgrass stress resistance. A 2-year field study was conducted in East Lansing, Michigan, during the 2024–2025 and 2025–2026 autumn/winter seasons to analyse leaf clippings before cold acclimation, during early Nov and late autumn, and post-snow and/or ice melt for total wax content and composition. Creeping bentgrass had 2.69 and 2.53 times more wax coverage than annual bluegrass across sampling dates in the experimental years. Cold acclimation increased wax content in creeping bentgrass during early Nov, but this was not observed in annual bluegrass. The increase in wax was mainly due to C₂₉-nonacosane and C₂₆-hexacosanol, which together accounted for over 82.5% of the total wax across both species and samplings. Creeping bentgrass showed greater variation and retained more wax during winter than annual bluegrass, possibly aiding winter stress tolerance.