Thursday, November 16, 2006 - 8:00 AM
316-1

Interactive Effects of Soil Saturation and High Temperature on Kentucky Bluegrass.

Yiwei Jiang, Agronomy Dept, Purdue University-Agronomy Dept., Purdue University, 915 W. State Street, West Lafayette, IN 47907 and Kehua Wang, Purdue University, 915 W State St., Department of Agronomy, West Lafayette, IN 47907.

Low oxygen stress in saturated soil often interacts simultaneously with high temperatures during summer time, which can cause rapid damage to grass plants.  The objective of this study was to determine physiological and biochemical traits of two Kentucky bluegrass (Poa pratensis L.) cultivars ('Unique' and 'Serene') in response to soil saturation alone or in combination with high temperature. Grasses were subjected to four treatments: 1) well-drained control under cool temperature (20C/15C, day/night); 2) waterlogging (WL) under cool temperature; 3) well-drained under high temperature (35C/30C, day/night); and 4) WL under high temperature (HT). After 5 d of treatment, grasses exposed to WL plus HT were well-drained under cool temperature for recovery. Turf quality dropped to 3.5 at 5 d of the combined WL and HT, while WL or HT treatment alone remained acceptable quality of 6.9 for both cultivars at 10 d of treatment. A significant decrease in chlorophyll content and photochemical efficiency (Fv/Fm) was observed in WL plus HT but not in WL or HT alone at 5 d of treatment. Turf quality, chlorophyll content and Fv/Fm under WL plus HT did not change after 5 d of recovery. Anaerobic metabolisms and profiles of stress protein for grasses under four treatments are being analyzed.