Effect of Plant Growth Regulators on Creeping Bentgrass Shade Stress Physiology.

The maintenance of quality turf in shaded areas present problems for even the most competent turfgrass managers.  It is estimated that 20% of the turf grown in United States is subjected to some degree of shade. The objective of this study was to better understand the response of creeping bentgrass to plant growth regulators under shade stress. Creeping bentgrass cultivar Penn G2 was treated with Primo (GA inhibitor), Phenidone (JA inhibitor) and n-Propyl gallate (chemical agent affecting photosynthesis function) under shaded and non-shade conditions. Plants were covered with silver cloth with 50% light reduction to simulate shade stress conditions. Salicylic acid (SA), Abscisic acid (ABA), Indole Acetic acid (IAA), and Gibberellic acid isoform 4 (GA4) content were up-regulated under shaded conditions compared to non-shade control. Higher content of GA1 were found in primo treated plants under shade while GA4 levels were higher in shaded plants treated with primo and n-propyl gallate compared to other treatments. This study provided better understanding of shade stress physiology and will help in providing better management strategy involving plant growth regulators for shade stress adaptation.