Effect of Plant Growth Regulators on Agrostis Stolonifera Growth during Combined Heat and Salt Stress.

Abiotic stresses, including heat and salt stress, often occur simultaneously and are detrimental to plant health and growth.  Heat and salt stress may interact to exacerbate negative effects.  As the climate continues to change and water conservation efforts continue, including the use of reclaimed water, turfgrass managers may face the co-occurrence of heat and salt stress more often.   The symptoms of salt and heat stress are similar to each other and both stresses can alter phytohormone levels and transport.  However, there is evidence that at a molecular level plant response may vary with the different stresses.  Plant growth regulators can have positive effects on plant health, including during periods of stress.  These positive effects are associated with altered phytohormone levels.  Studies were conducted in growth chambers in order to determine whether or not various plant growth regulators can improve creeping bentgrass (Agrostis stolonifera) health and growth during heat and salt stress and if so, to what extent.    Creeping bentgrass plants were subjected to 10 days of heat and salt stress and chemical treatments included gibberellin synthesis-inhibitors, an ethylene synthesis-inhibitor and 2,4-dichlorophenoxyacetic acid (2,4-D).  At the end of 10 days plants were harvested and fresh root and shoot weights, shoot chlorophyll content and root electrolyte leakage were measured and compared between the various treatments.