Effects of Salicylic Acid on Heat Tolerance Associated with Antioxidant Metabolism in Kentucky Bluegrass

Abstract

tase and CAT are the most effective antioxidant enzymes in scavenging AOS (Bowler et al., 1992).Turf quality of Kentucky bluegrass (Poa pratensis L.) often declines during summer when temperatures exceed its optimum range.Various cultural practices such as irrigation, fertiliza-This study was designed to determine whether application of salicylic tion, and soil cultivation have been extensively investiacid (SA) to the shoots and soil could improve heat tolerance of gated to improve turf performance in cool-season turf-Kentucky bluegrass, and to investigate whether SA-induced heat tolgrass during summer stress. However, limited information erance is related to changes in antioxidant activities. Effects of SA is available on the use of hormones or plant growth reguat different concentrations (0, 0.1, 0.25, 0.5, 1, and 1.5 mmol) on heat lators in heat stress management for cool-season turftolerance were examined in Kentucky bluegrass exposed to 46؇C for 72 h in a growth chamber. Influences of SA on the production of grasses and results vary with chemistry types. Kentucky active oxygen species (AOS), superoxide anion (O 2 . Ϫ ), and hydrogen bluegrass plants treated with trinexapac-ethyl, a synperoxide (H 2 O 2 ), and activities of antioxidant enzymes, superoxide thetic gibberellic acid inhibitor, were less heat tolerant dismutase (SOD), and catalase (CAT), were examined. Among SA than untreated plants (Heckman et al., 2002). Humic concentrations, 0.25 mmol was most effective in enhancing heat tolersubstances and seaweed extracts that contain phytohorance in Kentucky bluegrass, which was manifested by improved regrowth potential following heat stress of 72 h and maintenance of mones were reported to improve turfgrass stress tolerleaf water content at 77% during the 12-h stress period similar to that ance in various turfgrass species (Zhang et al., 2003a, under normal temperature conditions. The O 2 . Ϫ generating rate in-2003b). Other organic compounds such as ascorbic acid creased significantly at 6 h of heat stress, and SOD activity increased were used as free radical scavengers to alleviate oxidasignificantly at 2 h but decreased to the control level at 6 h of heat tive stress in various species (Zhang and Kirkham, stress in SA-untreated plants. The SA application suppressed the 1996). Salicylic acid has been defined as a new potential increase of O 2 . Ϫ generating rate and enhanced SOD activity significantly at 2 and 6 h of heat stress, respectively. The SA application decreased plant hormone (Raskin, 1992a) and found to play an H 2 O 2 level significantly at 2 and 12 h of heat stress, and increased important role in disease resistance (Raskin, 1992b) and CAT activity significantly within 12 h of heat stress. The results suggest

Heat stress protection in Aspen sp1 transgenic Arabidopsis thaliana

“…Although the present measurements of water content were not significant between transgenic and wild type plants, the former did exhibit higher water content than wild type plants. Moreover, another study found 0.25 mmol salicylic acid (SA) to be most effective in enhancing heat tolerance in Kentucky bluegrass, which was manifest by improved re-growth potential following heat stress of 72 h and maintenance of leaf water content at 77% during the 12 h stress period similar to that under normal temperature conditions (18). Heat stress was associated with a 3.6% higher water content in Kentucky bluegrass plants as compared with untreated plants (18).…”

Exogenous salicylic acid alleviates cold damage by regulating antioxidative system in two barley (Hordeum vulgareL.) cultivars

“…Hydrogen peroxide concentrations were measured by monitoring the absorbance at 410 nm of the titaniumperoxide complex according to He et al (2005). One mL of supernatant extracted with cold acetone was added to 0.1 mL 20% titanium reagent and 0.2 mL 17 mol ammonia solution.…”

High temperature-induced oxidative stress inLens culinaris, role of antioxidants and amelioration of stress by chemical pre-treatments

“…A promising area for increasing resistance of crops to thermal stress is by the use of chemical treatments like salicylic acid, abscisic acid and calcium chloride (Larkindale and Knight 2002;Chakraborty and Tongden 2005;He et al 2005). Acquisition of thermotolerance is likely to be of particular importance to plants that experience daily temperature fluctuations and are unable to escape to more favorable environments.…”