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Exogenous cinnamic acid regulates antioxidant enzyme activity and reduces lipid peroxidation in drought-stressed cucumber leaves

100%

Sun W.-J., Nie Y.-X., Gao Y., Dai A.-H., Bai J.-G.

Acta Physiologiae Plantarum

2012

tom 34

nr 2

To investigate the physiological mechanisms of drought stress mitigated by exogenous cinnamic acid (CA), cucumber seedlings were pretreated with 50 µM CA for 2 days and then were subjected to 10% polyethylene glycol (PEG) 6000. We examined if CA protects plants from PEGinduced drought stress, and whether the protective effect is related to antioxidant and lipid-peroxidation regulation. 2 days of CA application enhanced the activities of guaiacol peroxidase (GPX), glutathione peroxidase (GSH-Px), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) and increased the levels of ascorbate, proline, soluble sugar, vanillic acid (VA) and CA in leaves. After CA-pretreated leaves were exposed to drought, the activities of superoxide dismutase (SOD), catalase, ascorbate peroxidase, monodehydroascorbate reductase, GPX, GSH-Px, DHAR and GR were higher than under drought stress alone, while the levels of reduced glutathione, ascorbate, proline, soluble sugar,VAand CA in leaves were more. The combination of exogenous CA and drought led to higher transcript levels of Cu/Zn-SOD and Mn-SOD genes and decreased contents of malonaldehyde and hydrogen peroxide, but drought had adverse effects on them. Furthermore, the combined effects of exogenous CA and drought made 61.67% leaf edges dried, while drought resulted in 95.83% withered leaves. We conclude CA pretreatment leads to higher contents of CA and VA in drought-stressed leaves and thereby results in higher antioxidant activities directly or indirectly via proline and soluble sugar, thus increasing drought tolerance of cucumber. We also propose soluble sugar can reduce reactive oxygen species and decrease lipid peroxidation when exogenous CA mitigates drought stress.

Paraquat pre-treatment increases activities of antioxidant enzymes and reduces lipid peroxidation in salt-stressed cucumber leaves

100%

Lin S.-H., Liu Z.-J., Xu P.-L., Fang Y.-Y., Bai J.-G.

Acta Physiologiae Plantarum

2011

tom 33

nr 2

To investigate whether paraquat (PQ) is involved in regulation of antioxidant enzymes and lipid peroxidation under short-term salt stress, and to elucidate the physiological mechanism of salt stress mitigated by PQ, a cucumber cultivar (cv. Chunguang no. 2) was exposed to 100 mM NaCl for 48 h after pre-treatment with 10 µM PQ for 1 h. When compared to the control, salt stress increased the levels of malonaldehyde (MDA), superoxide radical (O₂⁻) and hydrogen peroxide (H₂O₂) and the activities of antioxidant enzymes, such as superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11) and glutathione reductase (EC 1.6.4.2) in the cucumber leaves. Under salt conditions, PQ pre-treatment prevented oxidative stress as observed by the decreases in MDA, H₂O₂ and O₂⁻ that correlated with the increase in antioxidant defenses. We propose that, at low concentrations, the PQ pre-treatment can reduce the salt-induced oxidative damage by increasing the antioxidative mechanisms in cucumber plants.

Caffeic acid protects cucumber against chilling stress by regulating antioxidant enzyme activity and proline and soluble sugar contents

72%

Wan Y.-Y., Zhang Y., Zhang L., Zhou Z.-Q., Li Y., Shi Q., Wang X.-J., Bai J.-G.

Acta Physiologiae Plantarum

2015

tom 37

nr 01

To investigate the physiological mechanism underlying chilling stress mitigation by exogenous caffeic acid (CA), we pretreated Cucumis sativus cv. Jinchun no. 4 seedlings with CA for 2 days, followed by exposure to normal (25/18 C) or cold (15/8 C) temperatures for 1 day.We chose 25 lM as the optimum CA concentration, since it produced lower levels of superoxide anion radical, hydrogen peroxide and malondialdehyde in chilling-stressed leaves than other concentrations of CA. Chilling treatment caused 50 % of the second leaves be withered, reduced the relative water content in the leaves and inhibited plant growth. Pretreatment with 25 lMCA alleviated the damaging effects of chilling. When the CA-pretreated seedlings were exposed to chilling, the superoxide dismutase, guaiacol peroxidase, catalase glutathione peroxidase, monodehydroascorbate reductase, ascorbate peroxidase, glutathione reductase and dehydroascorbate reductase activities were higher than those produced by chilling treatment alone, which coincided with increased transcript levels of copper/zinc superoxide dismutase, glutathione peroxidase and manganese superoxide dismutase genes; these results are consistent with the increased contents of ascorbate and glutathione. The application of 25 lM CA also increased the contents of endogenous CA and ferulic acid, as well as proline and soluble sugars, in chilling-stressed leaves. Therefore, exogenous CA treatment increases endogenous CA levels, induces antioxidant enzyme activity and reduces the levels of reactive oxygen species under chilling stress, thus protecting cucumber from chilling stress. Soluble sugars and proline are involved in the CA-mitigated chilling stress response.

Ograniczanie wyników

3 Acta Physiologiae Plantarum

3 Bai J.-G.

1 Dai A.-H.

1 Fang Y.-Y.

1 Gao Y.

1 Li Y.

1 Lin S.-H.

1 Liu Z.-J.

1 Nie Y.-X.

1 Shi Q.

1 Sun W.-J.

1 Wan Y.-Y.

1 Wang X.-J.

1 Xu P.-L.

1 Zhang L.

1 Zhang Y.

1 Zhou Z.-Q.

1 2015

1 2012

1 2011

Wyniki wyszukiwania

Exogenous cinnamic acid regulates antioxidant enzyme activity and reduces lipid peroxidation in drought-stressed cucumber leaves

Paraquat pre-treatment increases activities of antioxidant enzymes and reduces lipid peroxidation in salt-stressed cucumber leaves

Caffeic acid protects cucumber against chilling stress by regulating antioxidant enzyme activity and proline and soluble sugar contents