Cotton Leaf Senescence can be Delayed by Nitrophenolate Spray Through Enhanced Antioxidant Defence System
| Autor: | J. Annie Sheeba, D. Durga Devi, U. Bangarusamy ., Maduraimuthu Djanaguiraman |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
chemistry.chemical_classification
Reactive oxygen species Antioxidant biology Membrane permeability medicine.medical_treatment Glutathione peroxidase food and beverages Plant Science Ascorbic acid APX Lipid peroxidation Superoxide dismutase chemistry.chemical_compound Biochemistry chemistry Agronomy medicine biology.protein Food science Agronomy and Crop Science |
| Zdroj: | Journal of Agronomy and Crop Science. 195:213-224 |
| ISSN: | 1439-037X 0931-2250 |
| DOI: | 10.1111/j.1439-037x.2009.00360.x |
| Popis: | Leaf senescence is an oxidative process, and most of the catabolic processes involved in senescence are propagated irreversibly once initiated. An experiment was conducted to test the hypothesis that nitrophenolates (Atonik, a plant growth regulator) spray can delay the leaf senescence through reduced oxidative damage. Atonik 3.75 g a.i. ha ―1 was sprayed during boll filling stage on cotton, and the senescence process was evaluated by quantifying total chlorophyll contents, photosynthetic rate, Fv/Fm ratio, various reactive oxygen species (ROS) content, antioxidant content and antioxidant enzyme activity from 90 days after sowing (DAS) to 130 DAS. The result indicated that nitrophenolate spray reduced the hydrogen peroxide (H 2 O 2 ), superoxide anion (O 2 ― ) accumulation, lipid peroxidation (malondialdehyde), lipoxygenase activity and membrane permeability over unsprayed control. The antioxidant enzyme activity (superoxide dismutase, SOD; ascorbate peroxidase, APX; peroxidase, POX; glutathione peroxidase, GSH-Px) were significantly increased by the nitrophenolate spray. POX (118.1 %) and GSH-Px (143.3 %) activities were enhanced to a higher level compared to APX (8.5 %) activity at 130 DAS. Enhanced accumulation of ascorbate (144.9 %), phenol (154.7 %) and proline (50 %) was seen in nitrophenolate-sprayed plants compared with unsprayed control plants at 130 DAS. Ascorbate content is increased by higher dehydro-ascorbate reductase enzyme activity. Ascorbate was thus able to replenish reducing equivalents to phenoxyl radicals resulting in an increase in phenolic compounds. The increased phenolic acid content may be involved in scavenging the ROS produced during senescence process. The higher level of reduced ascorbate and low level of endogenous H 2 O 2 in the leaves may be the prerequisite for delayed leaf senescence in the nitrophenolate-sprayed plants. Based on the present work, it can be concluded that nitrophenolate-sprayed plants can postpone the leaf senescence by peroxide/phenolic/ascorbate system which is involved in scavenging the ROS produced during leaf senescence. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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