Exogenous Application of Proline and Salicylic Acid can Mitigate the Injurious Impacts of Drought Stress on Barley Plants Associated with Physiological and Histological Characters

Khaled A A Abdelaal,Abdelghafar M Abu-Elsaoud,Dalia S Tantawy,Abdelhalim I Ghazy,El-Sayed E El-Shawy,Abdullah A Al-Doss,Mohamed M El-Afry,Salman F Alamery,Kotb A Attia,Yaser M Hafez

doi:10.3390/su12051736

Khaled A A Abdelaal, Abdelghafar M Abu-Elsaoud + Show 8 more

Open Access

https://doi.org/10.3390/su12051736

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Abstract

Barley is a very important crop worldwide and has good impact in preserving food security. The impacts of 10 mM proline and 0.5 mM salicylic acid were evaluated on water stressed barley plants (Hordeum vulgare L. Giza126). Salicylic acid and proline treatments led to increased stem length, plant dry weights, chlorophyll concentration, relative water content, activity of antioxidant enzymes, and grain yield under drought stress. Nevertheless, lipid peroxidation, electrolyte leakage (EL), superoxide (O2·−), and hydrogen peroxide (H2O2) significantly decreased in treated barley plants with proline and salicylic acid in both growing seasons as compared with drought treatment only, which caused significant decrease in stem length, plant dry weights, chlorophyll concentration, activity of antioxidant enzymes, as well as biological and grain yield. These results demonstrated the importance of salicylic acid and proline as tolerance inducers of drought stress in barley plants.

Highlights

The barley (Hordeum vulgare L.) plant belongs to the family Poaceae, playing a main role in human food and animal feeding [1]
The results showed that Catalase activity (CAT), POX, and Polyphenol oxidase (PPO) enzyme activities were increased significantly by exposure to drought stress (Figure 4A,C)
This research was planned to examine the impact of proline and salicylic acid on barley plants under drought stress

Summary

Introduction

The barley (Hordeum vulgare L.) plant belongs to the family Poaceae, playing a main role in human food and animal feeding [1]. The production of barley grains was around 142.37 million tons in 2017/2018 (www.statista.com/statistics/271973/world-barley-production). It was influenced by environmental factors, drought. Drought is a very damaging factor which causes decreases in morphological and physiological parameters and reduces plant growth and production [2]. The plants under deficit water stress have distinctive morphological symptoms such as wilting, etiolation, yellowing, and leaf downfall [4,5]. Stomatal closure and reduction in CO2 concentration are the first responses to drought stress in leaves, reducing photosynthetic activity. The stomatal density too is associated with tolerance of drought stress [6]. Drought stress led to significant reductions in chlorophyll concentrations and yield characters of flax plants [7]

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Conclusion