Alterations in seedling vigour and antioxidant enzyme activities in Catharanthus roseus under seed priming with native diazotrophs

This research was performed to explore the vital role of seed priming with a 0.01 µM concentration of brassinosteroids (EBL) to alleviate the adverse effects of Cr (100 µM) in two different rice cultivars. Seed priming with EBL significantly enhanced the germination attributes (germination percentage, germination energy, germination index, and vigor index, etc.), photosynthetic rate as well as plant growth (shoot and root length including the fresh and dry weight) under Cr toxicity as compared to the plants primed with water. Cr toxicity induced antioxidant enzyme activities (SOD, POD, CAT, and APX) and ROS level (MDA and H2O2 contents) in both rice cultivars; however, a larger increment was observed in YLY-689 (tolerant) than CY-927 (sensitive) cultivar. EBL application stimulatingly increased antioxidant enzyme activities to scavenge ROS production under Cr stress. The gene expression of SOD and POD in EBL-primed rice plants followed a similar increasing trend as observed in the case of enzymatic activities of SOD and POD compared to water-primed rice plants. Simultaneously, Cr uptake was observed to be significantly higher in the water-primed control compared to plants primed with EBL. Moreover, Cr uptake was significant in YLY-689 compared to CY-927. In ultra-structure studies, it was observed that EBL priming relieved the rice plants from sub-cellular damage. Conclusively, our research indicated that seed priming with EBL could be adopted as a promising strategy to enhance rice growth by copping the venomous effect of Cr.

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Seed priming with hydrogen peroxide alleviates the effects of drought stress in rice (Oryza sativa L.) seedlings

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha48111829 ◽

2020 ◽

Vol 48 (1) ◽

pp. 273-283

Author(s):

Weeraphorn JIRA-ANUNKUL ◽

Wattana PATTANAGUL

Keyword(s):

Hydrogen Peroxide ◽

Oryza Sativa ◽

Drought Stress ◽

Antioxidant Enzyme ◽

Enzyme Activities ◽

Oryza Sativa L ◽

Seed Priming ◽

Rice Seedling ◽

Antioxidant Enzyme Activities ◽

Guaiacol Peroxidase

Drought stress is a major factor limiting crop growth and yield. Hydrogen peroxide (H2O2) is known as a signalling molecule in the plant cell in which activates multiple physiological changes that play essential roles in tolerance mechanism. This study investigated the effects of seed priming with H2O2 on growth, some physiological characteristics and antioxidant enzyme activities in rice seedling under drought stress. Rice (Oryza sativa L.) cv. Khao Dawk Mali 105 seeds were primed with 0 (distilled water), 1, 5, 10, and 15 mM H2O2 and grown for 21 days. The seedlings were subjected to drought stress by withholding water for 7 days. The results showed that priming with low concentrations of H2O2 improved plant growth and biomass as well as relative water content, malondialdehyde content, electrolyte leakage. Priming with H2O2, however, had no beneficial effect on chlorophyll content, proline and leaf total soluble sugar. Seed priming with appropriate levels of H2O2 also enhanced antioxidant enzyme activities including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX). It is concluded that seed priming with 2-10 mM H2O2, is beneficial for enhancing drought tolerance in rice seedling by increasing antioxidant capacity, which in turn reduces oxidative stress and damages to the cellular components.

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