Glutamic Acid Foliar Application Enhances Antioxidant Enzyme Activities in Kimchi Cabbages Leaves Treated with Low Air Temperature

Water stress negatively affects productivity in crops, while the foliar application of potassium-containing compounds may be helpful in reducing the drought effects. This study evaluated the efficacy of foliar applied potassium chloride (control - distilled water spray -, 3 and 6 mM-1) on tomato plants under drought stress. Three irrigation levels were maintained at 100, 75 and 50% according to evapotranspiration designated as well watered, moderate and severe drought stressed. Increasing drought stress significantly reduced plant growth and yield. The foliar applied KCl produced maximum leaf area, stem diameter and length, plant yield under each drought stress conditions compared to control. The minimum of growth factors were obtained by control under severe stress. Highest yield per plant was also recorded for foliar applied KCl under moderate condition than other treatments. Foliar applied KCl alone decreased the SOD, CAT and PPO in well-watered condition but KCl application on tomato plants under drought stress induced the antioxidant enzyme activities more than control well-watered treatment.

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Enhancement of antioxidant enzyme activities and primary photochemical reactions in response to foliar application of thiols in water-stressed pearl millet

Acta Agronomica Hungarica ◽

10.1556/aagr.57.2009.1.3 ◽

2009 ◽

Vol 57 (1) ◽

pp. 21-31 ◽

Cited By ~ 7

Author(s):

S. D’souza ◽

N. Nathawat ◽

J. Nair ◽

P. Radha Krishna ◽

N. Ramaswamy ◽

...

Keyword(s):

Antioxidant Enzyme ◽

Pearl Millet ◽

Enzyme Activities ◽

Foliar Application ◽

Pennisetum Glaucum ◽

Photochemical Reactions ◽

Antioxidant Enzyme Activities ◽

Sod Activity ◽

Thiol Compounds ◽

Ps Ii

Primary photochemical reactions and the activities of the antioxidant enzymes chloroplastic superoxide dismutase (SOD), glutathione reductase (GR) and glutathione-S-transferase (GST) were determined in water-stressed pearl millet ( Pennisetum glaucum L. cv. HHB-67) plants sprayed with the thiol compounds dithiothreitol (DTT), thioglycolic acid (TGA) and thiourea (TU) and the thiol modifiers 5,5′-dithio-bis-2-nitrobenzoic acid (DTNB) and N-ethylmaleimide (NEM) at the earhead emergence stage (47 days after sowing, DAS), together with a control. Sampling was done at 54 and 67 days after sowing. Photosystem I and II (PS I and II) activities (ferricyanide site) were found to increase in plants sprayed with TU, TGA and DTT at both stages (54 and 67 DAS), but a reduction in PS II activity (DCQ Site) compared with the control was caused by NEM (66.66%) and DTNB (27.77%) at 54 DAS. A similar decrease in the activity of PS II (ferricyanide site) was found at 67 DAS for DTNB (55.55%). The chloroplastic SOD activity increased in chloroplasts isolated from leaves sprayed with thiol compounds at both sampling stages, except for NEM at 54 and 67 DAS. The activities of GR and GST in the leaves were higher in thiol-treated plants than in the control at 54 and 67 DAS, while the lowest GR activity was seen for the sulphydryl modifiers (DTNB and NEM) in leaves at 54 DAS. The experimental data suggest an enhancement in the primary photochemistry and antioxidant enzyme activities of water-stressed pearl millet in response to foliar spraying with thiol compounds.

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