The Effects of Nitrogen, Cytokinin, and Ethylene Inhibitors On the Suppression of Leaf Senescence and Improvement of Heat Tolerance in Creeping Bentgrass.

Heat is a major abiotic stress effecting creeping bentgrasses leading to premature senescence and a major decline in overall quality. Previous studies have separately shown that applications of nitrogen, cytokinins or ethylene inhibitors may have a beneficial role for heat tolerance and delaying damaging stress induced senescence, although the mechanisms of such treatments are not fully understood. ‘Penncross’ plugs were transferred to plastic pots and moved to a growth chamber. After plants had established heat stress was induced (35/30 C day/night temperatures). Exogenous applications of nitrogen, cytokinin, an ethylene inhibitor, or a combination of all three, at previously determine effective rates, were applied three days prior to the stress treatment and then at weekly intervals during the stress period. Throughout the stress period overall turf quality rating were taken along with chlorophyll content, photosynthetic efficiency, and canopy height measurements to estimate the progress of leaf senescence and plant health. In addition to this tissue samples were collected to be used for protein analysis.  Changes in protein levels associated with treatments were determined using 2-D gel electrophoresis and confirmed using western blots.  Examining the protein changes associated with these treatments under heat stress will help determine important mechanisms responsible for delaying senescence and creating more heat tolerant plants.