Influence of Controlled Condition Ice Encasement of Creeping Bentgrass and Annual Bluegrass on Plant Recovery, Gas Evolution, and Metabolites

Abstract

Two cool-season putting green turfgrass species, annual bluegrass and creeping bentgrass, are differential in ice encasement tolerance. Physiological mechanisms associated with creeping bentgrass ice encasement tolerance and annual bluegrass susceptibility are not understood. The objectives were to evaluate oxygen, ethylene, and CO2 content within the upper soil space of the plants while frozen and immediately after ice melt after 0, 5, 10, 20, and 28 days of ice encasement (2.54 cm of ice) in growth chamber conditions. Following ice melt, plant samples were separated into leaf, crown, and root tissues and used to evaluate carbohydrate and amino acid content. Annual bluegrass exhibited higher damage (slower recovery rates) on most sampling days compared with creeping bentgrass. The organs that were most damaged and exhibited a differential principal component analysis snapshot, were the leaf and crown tissues. Creeping bentgrass may preserve leaf and crown tissues for postwinter recovery whereas significant metabolic changes occur in annual bluegrass leaves and crowns. Creeping bentgrass retained total amino acids in leaves following ice encasement whereas total leaf amino acid levels declined in annual bluegrass. Specific carbohydrates and amino acids such as the ability to maintain high levels of fructose, asparagine, and proline may be important indicators of the tolerance to ice encasement stress. On the basis of more prominent carbohydrate and amino acid loss in leaves and crowns and higher levels of CO2 evolution, annual bluegrass may exhibit a higher metabolism and/or tissue damage during ice encasement compared with creeping bentgrass, which could reduce spring recuperative potential.