Salicylic-Acid-Regulated Antioxidant Capacity Contributes to Growth Improvement of Okra (Abelmoschus esculentus cv. Red Balady)

Sabry M Youssef,Antonio A Calderón,Antonio López-Orenes,María A Ferrer

doi:10.3390/agronomy12010168

Abstract

The improvement of crop yield and quality are currently of prime concern to achieve global food security and sustainability. Plant elicitation with salicylic acid (SA) has been shown to play a key role in regulating plant growth and productivity. Here, the effects of foliar SA application (1, 2, and 4 mM) on antioxidant capacity and phenolic metabolism, among other biochemical parameters, were studied in okra leaves. The results showed that SA treatments markedly increase the levels of endogenous free SA and trigger the accumulation of chlorophylls, soluble proteins, proline, antioxidant capacity, and phenolic compounds, alongside the stimulation of the enzymatic activities of phenylalanine ammonia-lyase and peroxidase, with these changes being paralleled by decreased levels of lipid peroxidation. The beneficial effects of SA treatments were also tested on field-grown okra plants. Results revealed that yield-associated agronomic attributes significantly increased upon SA treatments, especially at 2 mM SA. Altogether, these results point to a connection between SA-induced antioxidant system strengthening and crop growth and productivity. Therefore, foliar application of SA seems to be a potent and workable approach to enhance okra crop quality and yield.

Highlights

Okra (Abelmoschus esculentus (L.) Moench), known as lady’s fingers, gumbo, bhindi, or bamya, is an important warm-season, fast-growing, annual crop of the mallow family
Okra production is around 9.9 Mt, with more than 74% of its production concentrated in low-income, food-deficit countries (LIFDCs), the LIFDCs’ average yield is half that found in the European Union [7]
These studvealed that the salicylic acid (SA)-induced growth-promoting effects are associated with the SA-mediated ies revealed that the SA-induced growth-promoting effects are associated with the activation of photosynthetic capacity, including the net photosynthetic rate, carboxylaSA-mediated activation of photosynthetic capacity, including the net photosynthetic rate, tion efficiency, efficiency, and chlorophyll content, ascontent, well as nitrate resulting in carboxylation and chlorophyll as wellreductase as nitrateactivity, reductase activity, enhanced crop yield

Summary

Introduction

Okra (Abelmoschus esculentus (L.) Moench), known as lady’s fingers, gumbo, bhindi, or bamya, is an important warm-season, fast-growing, annual crop of the mallow family. Abelmoschus esculentus is an ancient crop of African origin, mostly cultivated within tropical and subtropical regions worldwide for its immature pods and tender leaves, which are consumed as vegetables [2,3]. Okra production is around 9.9 Mt, with more than 74% of its production concentrated in low-income, food-deficit countries (LIFDCs), the LIFDCs’ average yield is half that found in the European Union [7]. The use of chemical priming is considered an important tool to improve crop quality and to mitigate the effects of environmental stress in plants at a minimal fitness cost [8]. Accumulating evidences demonstrated that the use of low concentrations of phytohormones can prime plant stress tolerance [9].

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Discussion

Conclusion