Effects of Trinexapac‐Ethyl Foliar Application on Creeping Bentgrass Responses to Combined Drought and Heat Stress

Abstract

Simultaneous drought and heat stress is detrimental to turfgrass growth. Growth regulators may influence plant responses to stresses. The objective of this study was to determine effects of pretreatment with trinexapac‐ethyl (TE) on creeping bentgrass (Agrostis stolonifera L.) responses to subsequent exposure to combined heat and drought stress. Plants were treated with TE (1.95 mL L−1 [v/v], Primo Maxx) every 14 d for 42 d and then exposed to combined drought and heat (35°C) in growth chambers. Application of TE increased turf quality and relative water content and chlorophyll content during 21 d of stress. Trinexapac‐ethyl–treated plants had increased growth rate and maintained constant canopy photosynthetic rate (Pn) and photochemical efficiency (Fv/Fm) during the stress period, while these parameters declined for the untreated control. Trinexapac‐ethyl–treated plants maintained lower evapotranspiration rate (ET) under nonstressed control conditions, but higher ET at 21 d of stress. Trinexapac‐ethyl–treated plants showed no differences from untreated plants in osmotic adjustment, and had lower levels of total nonstructural carbohydrates during the stress period. The study suggests that TE application enhanced turf performance under stress, as demonstrated by maintenance of higher turf quality and growth rate during a prolonged period of com bined stress. The beneficial effects of TE on bentgrass stress responses could be related to the maintenance of photosynthetic activities and greater level of cellular hydration. These and other published data indicate that use of TE on creeping bentgrass that seasonally experiences heat and drought stresses could benefit its performance.

Effects of Sequential Application of Plant Growth Regulators and Osmoregulants on Drought Tolerance of Creeping Bentgrass (Agrostis stolonifera)

“…Increased NDVI could be related to the suppression of vertical shoot growth, which may allocate carbohydrates or energy towards tiller production as previously reported for other turfgrass species (Ervin and Koski, 1998). Similarly, in other studies with perennial ryegrass (Lolium perenne L.) and creeping bentgrass, TE application did not significantly alter osmotic adjustment during drought stress ( Jiang and Fry, 1998;McCann and Huang, 2007). Previous studies have shown that foliar application of TE delayed leaf dehydration in creeping bentgrass but had limited or no effects on osmotic adjustment under combined drought and heat stress Huang, 2007, 2008).…”

Plant Growth Regulator and Soil Surfactants’ Effects on Saline and Deficit Irrigated Warm‐Season Grasses: I. Turf Quality and Soil Moisture

“…The benefits of TE applications have been previously documented in drought-stressed grasses (McCann and Huang, 2007) and in plants irrigated with saline water (Baldwin et al, 2006). In our experiment, TE had a positive effect on turf quality, especially on Princess 77.…”

Chemical plant protectants and plant growth regulator effects on annual bluegrass survival of ice cover

“…The chemical TE has been shown to decrease tolerance to heat stress in Kentucky bluegrass (Heckman, Horst, Gaussoin, & Young, ). However, TE has also been shown to play a role in improving heat tolerance when combined with drought stress in creeping bentgrass (McCann & Huang, ). Heckman et al.…”