Supraoptimal Soil Temperatures Induced Oxidative Stress in Leaves of Creeping Bentgrass Cultivars Differing in Heat Tolerance

Abstract

High temperature is a major factor limiting growth of cool‐season grasses during summer months. The objective of this study was to determine whether oxidative stress is involved in leaf injury induced by high soil temperatures in two creeping bentgrass (Agrostis palustris Huds.) cultivars, heat‐tolerant L‐93 and heat‐sensitive Penncross. Shoots and roots were exposed to four differential temperature regimes in growth chambers and water baths: (i) 20/20°C (control); (ii) 20/35°C (high soil temperature); (iii) 35/20°C (high air temperature); and (iv) 35/35°C (high shoot/soil temperatures). Turf quality, leaf photochemical efficiency (Fv/Fm), electrolyte leakage (EL), content of a lipid peroxidation product (malondialdehyde, MDA), and activities of the antioxidants superoxide dismutase (SOD) and catalase (CAT) were determined. Turf quality and leaf Fv/Fm ratio decreased, whereas EL and MDA contents increased under high soil temperature alone or in combination with high air temperature regimes in both cultivars, but to a greater extent in Penncross than in L‐93. Decreases in turf quality and Fv/Fm ratio and increases in EL and MDA were more pronounced at 20/35°C than at 35/20°C. The activities of SOD and CAT decreased with prolonged periods of high temperatures and to a greater extent for Penncross than for L‐93. The reductions in SOD and CAT activities were more severe at 20/35 than at 35/20°C. These results suggest that high soil temperature caused more severe oxidative damage to leaves than high air temperature by limiting antioxidant activities and inducing lipid peroxidation. This oxidative stress was associated with accelerated leaf senescence under high temperature conditions. Maintenance of antioxidant activities and low levels of lipid peroxidation was related to the better tolerance of creeping bentgrass to high soil temperature stress imposed on roots or high air temperature on shoots.

Effects of foliar application of nitrogen on the photosynthetic performance and growth of two fescue cultivars under heat stress

“…We found a trend of decrease in the maximal efficiency of PS 2 photochemistry (F v /F m ) and effective quantum yield of PS 2 reaction centres of irradiated sample (F v '/F m ') in leaves of the two cultivars under HT, which was in agreement with results of other studies on plants under HT (Huang et al 2001, Gesch et al 2003. The lower decrement of F v /F m and F v '/F m ' by N supply may result from the lower decrease of Chl content in leaves of the two cultivars pretreated with N. Furthermore, N supply can directly modify the F v /F m ratio as well as the qP and qNP (Ciompi et al 1996).…”

Growth, lipid peroxidation and photosynthesis in two tall fescue cultivars differing in heat tolerance

“…The lipid peroxidation in the leaf and root tissue was determined by estimating the malondialdehyde (MDA) content in according to Huang et al (2001). MDA content was measured spectrophotometrically (Hitachi U-3000) at 532 nm, after subtraction of non-specific absorption at 600 nm, using a coefficient of absorbance of 155 mM -1 cm -1 .…”

Leaf senescence and grain filling affected by post-anthesis high temperatures in two different wheat cultivars

“…When plants are exposed to high-temperature stress, chlorophyll biosynthesis is inhibited (Tewari and Tripathy 1998). Loss of chlorophyll is usually attributed to membrane damage and leaf senescence (Simon 1974;Liu and Huang 2000;Huang et al 2001).…”