Effects of Abscisic Acid on Antioxidant Systems of Stylosanthes guianensis (Aublet) Sw. under Chilling Stress

Abstract

Stylosanthes guianensis (Aublet) Sw. is an important pasture legume in tropical and subtropical countries. Chilling injury of S. guianensis is a serious problem in subtropical cultivated areas. An experiment was conducted under controlled conditions to study the effect of abscisic acid (ABA) on S. guianensis and its relation to antioxidant systems under chilling stress. Stylosanthes guianensis seedlings were sprayed with 10 mg L−1 ABA or water. One day later, the plants were transferred to a 10°C growth chamber and grown for 7 d with a 12‐h photoperiod at 160 μmol m−2 s−1 photosynthetic photon flux density. The chilling treated plants were then rewarmed to 28°C for 2 d. During the 9‐d treatment, a series of enzyme activities, relative water content (RWC), and electrolyte leakage were measured on sampled leaflets. The results showed that chilling increased electrolyte leakage of both water‐ and ABA‐treated plants, while RWC decreased under chilling conditions. ABA‐treated plants had lower electrolyte leakage and higher RWC than those of water‐treated plants. Activities of ascorbate peroxidase (APX) and catalase (CAT) and contents of reduced glutathione (GSH) and ascorbic acid (AsA) were transiently enhanced by ABA treatment before the plants were subject to chilling. ABA‐treated S. guianensis retained higher levels of superoxide dismutase (SOD), APX, GSH, and AsA than water‐treated ones under chilling conditions. The results suggested that ABA‐increased chilling resistance in S. guianensis is partially associated with enhanced scavenging systems.

Effects of low temperature and drought on the physiological and growth changes in oil palm seedlings

“…In this study, SOD and POD activities were initially increased and later, they were decreased with the increasing stress time (Figures 4 and 5). This was in accordance with observations of other studies (Guo et al, 2004;Zhou et al, 2005;Tan et al, 2006;Pan et al, 2006), which showed that the resistance of plants and the activities of SOD and POD decreased when they were exposed to excess environmental stress time, because the balance of the active oxygen metabolism system was affected. When the induced active oxygen was accumulated greatly, the cell membrane lipid peroxidation were initiated and accelerated, but when the levels of the active oxygen formed exceeded the ability of the antioxidant system to cope with them, damage to cellular components occurred (Okamoto et al, 2001;Suzuki and Mittler, 2006).…”

Antioxidant Activity of Several Cabbage (Brassica oleracea L.) Cultivars

“…The plant has antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) against ROS (reactive oxygen species) (Zhou et al, 2005). The production of activated oxygen species occurs when plants are subjected to stress conditions (Dionisio-Sese and Tobita, 1998).…”

Exogenous abscisic acid increases antioxidant enzymes and related gene expression in pepper (Capsicum annuum) leaves subjected to chilling stress

“…The increased tolerance is partly due to an enhanced antioxidant defense system that includes SOD, CAT, APX, and GR (Bellaire et al, 2000), and the AsA and GSH, which prevent the accumulation of ROS (Jiang and Zhang, 2002). Stylosanthes guianensis seedlings pretreated with ABA show increased chilling tolerance via increases in SOD activity and AsA and GSH levels, which provide little information about how AsA-GSH metabolism (e.g., APX, MDHAR, DHAR, and GR) regulates the scavenging of excess ROS (Zhou et al, 2005). ABA-mediated upregulation of genes such as APX, MDHAR, GR, and DHAR in Arabidopsis thaliana is involved in ROS scavenging through the AsA-GSH cycle, and ABAmediated AsA accumulation appear to be regulated by enhanced recycling at the transcriptional level (Ghassemian et al, 2008).…”