TY - JOUR
T1 - Role of abscisic acid in water stress-induced antioxidant defense in leaves of maize seedlings
AU - Jiang, Mingyi
AU - Zhang, Jianhua
N1 - Funding Information:
We are grateful for grants obtained from the Faculty Research Grant of Hong Kong Baptist University and the Research Grants Council of Hong Kong University Grants Committee. M. Jiang is grateful for the postgraduate studentship from Hong Kong Baptist University.
PY - 2002
Y1 - 2002
N2 - Roles of abscisic acid (ABA) in water stress-induced oxidative stress were investigated in leaves of maize (Zea mays L.) seedlings exposed to water stress induced by polyethylene glycol (PEG 6000). Treatment with PEG at -0.7 MPa for 12 and 24h led to a reduction in leaf relative water content (RWC) by 7.8 and 14.1%, respectively. Duration of the osmotic treatments is considered as mild and moderate water stress. The mild water stress caused significant increases in the generation of superoxide radical (O2-) and hydrogen peroxide (H2O2), the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) and the contents of ascorbate (ASC), reduced glutathione (GSH). The moderate water stress failed to further enhance the capacity of antioxidant defense systems, as compared to the mild water stress. The contents of catalytic Fe, which is critical for H2O2-dependent hydroxyl radical (•OH) production, and the oxidized forms of ascorbate and glutathione pools, dehydroascorbate (DHA) and oxidized glutathione (GSSG), markedly increased, a significant oxidative damage to lipids and proteins took place under the moderate water stress. Pretreatment with ABA caused an obvious reduction in the content of catalytic Fe and significant increases in the activities of antioxidant enzymes and the contents of non-enzymatic antioxidants, and then significantly reduced the contents of DHA and GSSG and the degrees of oxidative damage in leaves exposed to the moderate water stress. Pretreatment with an ABA biosynthesis inhibitor, tungstate, significantly suppressed the accumulation of ABA induced by water stress, reduced the enhancement in the capacity of antioxidant defense systems, and resulted in an increase in catalytic Fe, DHA and GSSG, and oxidative damage in the water-stressed leaves. These effects were completely prevented by addition of ABA, which raised the internal ABA content. Our data indicate that ABA plays an important role in water stress-induced antioxiclant defense against oxidative stress.
AB - Roles of abscisic acid (ABA) in water stress-induced oxidative stress were investigated in leaves of maize (Zea mays L.) seedlings exposed to water stress induced by polyethylene glycol (PEG 6000). Treatment with PEG at -0.7 MPa for 12 and 24h led to a reduction in leaf relative water content (RWC) by 7.8 and 14.1%, respectively. Duration of the osmotic treatments is considered as mild and moderate water stress. The mild water stress caused significant increases in the generation of superoxide radical (O2-) and hydrogen peroxide (H2O2), the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) and the contents of ascorbate (ASC), reduced glutathione (GSH). The moderate water stress failed to further enhance the capacity of antioxidant defense systems, as compared to the mild water stress. The contents of catalytic Fe, which is critical for H2O2-dependent hydroxyl radical (•OH) production, and the oxidized forms of ascorbate and glutathione pools, dehydroascorbate (DHA) and oxidized glutathione (GSSG), markedly increased, a significant oxidative damage to lipids and proteins took place under the moderate water stress. Pretreatment with ABA caused an obvious reduction in the content of catalytic Fe and significant increases in the activities of antioxidant enzymes and the contents of non-enzymatic antioxidants, and then significantly reduced the contents of DHA and GSSG and the degrees of oxidative damage in leaves exposed to the moderate water stress. Pretreatment with an ABA biosynthesis inhibitor, tungstate, significantly suppressed the accumulation of ABA induced by water stress, reduced the enhancement in the capacity of antioxidant defense systems, and resulted in an increase in catalytic Fe, DHA and GSSG, and oxidative damage in the water-stressed leaves. These effects were completely prevented by addition of ABA, which raised the internal ABA content. Our data indicate that ABA plays an important role in water stress-induced antioxiclant defense against oxidative stress.
KW - Abscisic acid
KW - Antioxidant defense system
KW - Oxidative damage
KW - Reactive oxygen species
KW - Water stress
KW - Zea mays
UR - http://www.scopus.com/inward/record.url?scp=0036023313&partnerID=8YFLogxK
U2 - 10.1080/1071576021000006563
DO - 10.1080/1071576021000006563
M3 - Journal article
C2 - 12448826
AN - SCOPUS:0036023313
SN - 1071-5762
VL - 36
SP - 1001
EP - 1015
JO - Free Radical Research
JF - Free Radical Research
IS - 9
ER -