Some Responses of Bluegrass to Herbicides and Temperature Variation

Abstract

Growth-chamber studies were conducted to determine some effects of MSMA (monosodium methanearsonate) and DCPA (dimethyl tetrachloroterephthalate) treatments on ‘Pennstar’ and common Kentucky Bluegrass (Poa pratensis L.), grown at three different temperatures. Herbicide was applied at recommended rates at the beginning of regrowth following mowing. At sampling time, height and weight were recorded and some fresh tissue was frozen for chlorophyll analysis and the rest was oven-dried for amino acid analysis. Chlorophyll content of ‘Pennstar’ was significantly increased by MSMA. Common bluegrass grown at 18 C had significantly higher levels of free amino acids than did ‘Pennstar’ grown at the same temperature. At 27 C, asparagine and alanine were significantly higher in common bluegrass than in ‘Pennstar.’ MSMA had a more significant effect on all detected free amino acid concentrations except cysteine in ‘Pennstar’ than in common bluegrass. DCPA was more active than MSMA on common bluegrass; all amino acids were increased significantly by treatment.