COOL-SEASON GRASS DEVELOPMENT RESPONSE TO ACCUMULATED TEMPERATURE FOLLOWING VARIABLE EXPOSURE TO BELOW-FREEZING TEMPERATURES

Authors: Bartholomew, Paul; Williams, Robert

Submitted to: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/2/2002
Publication Date: 11/1/2002
Citation: BARTHOLOMEW, P.W., WILLIAMS, R.D. COOL-SEASON GRASS DEVELOPMENT RESPONSE TO ACCUMULATED TEMPERATURE FOLLOWING VARIABLE EXPOSURE TO BELOW-FREEZING TEMPERATURES. CD-ROM. AGRONOMY SOCIETY OF AMERICA, CROP SCIENCE SOCIETY OF AMERICA, SOIL SCIENCE SOCIETY OF AMERICA MEETING. 2002. (A03-bartholomew101028-Poster)

Interpretive Summary: Abstract only

Technical Abstract: In several temperate grass species there is a linear relation between cumulative leaf appearance and accumulated temperature, or growing day degrees (GDD), above 0 °C. It is not known if this response is changed by short-term exposure to temperatures below freezing. Mainstem leaf appearance rate was measured on a GDD timescale in individual seedlings of Italian ryegrass (Lolium multiflorum Lam.), tall fescue (Festuca arundinacea Schreb.) and tall wheatgrass (Elytrigia elongata (Host) Nevski), grown in a growth chamber. Seedlings were either maintained continuously in a 15-0 °C day-night temperature regime or removed and exposed for 15-hour periods to air temperatures of -2.5, -5.0 or -7.5 °C. When seedlings were insulated during cold treatment, so that soil temperature did not fall below -2.7 °C, the average rate of leaf appearance in all three species was unaffected by up to four exposures to air temperatures of -2.5 or -5.0 °C. There was no effect on rate of leaf appearance in Italian ryegrass or tall fescue after four exposures to an air temperature of -7.5 °C but with tall wheatgrass there was a cumulative effect that reduced the rate of leaf appearance by up to 24%, compared with unexposed plants.