Eragrostis curvula: Influence of Low Temperatures on Starch Accumulation, Amylolytic Activity, and Growth1

Abstract Four varieties of Eragrostis curvula (Schrad.) Nees (weeping lovegrass) were evaluated for growth at reduced temperatures, amylolytic activity, and diurnal changes in leaf starch content in order to ascertain whether the variety with the most relative growth at reduced temperatures would retain the least amount of leaf starch after a cool night. Growth was measured by dry matter production; amylolytic activity by the ability of a leaf extract to hydrolyze starch; and leaf starch by enzymic hydrolysis of the starch followed by a glucose assay. It was found that growth at reduced temperature was positively associated with amylolytic activity and negatively associated with leaf starch retention after a cool night. Differences in amylolytic activity were due to the total amount of enzyme activity present and not due to differences in enzymic resistance to cool temperatures. The Q10 for amylolytic activity of all varieties was 2.0. These findings suggest that amylolytic activity and leaf starch measurements might be useful selection criteria in the search for cool temperature resistant tropical grass forages.