Ferulic Acid and Salicylic Acid Foliar Treatments Reduce Short-Term Salt Stress in Chinese Cabbage by Increasing Phenolic Compounds Accumulation and Photosynthetic Performance.

Branka Salopek-Sondi,Ana Smolko,Ida Linić,Lidija Brkljačić,Selma Mlinarić,Iva Pavlović

doi:10.3390/plants10112346

Abstract

Salinity stress is one of the most damaging abiotic stresses to plants, causing disturbances in physiological, biochemical, and metabolic processes. The exogenous application of natural metabolites is a useful strategy to reduce the adverse effects of stress on crops. We investigated the effect of foliar application of salicylic acid (SA) and ferulic acid (FA) (10–100 μM) on short-term salt-stressed (150 mM NaCl, 72 h) Chinese cabbage plants. Subsequently, proline level, photosynthetic performance, phenolic metabolites with special focus on selected phenolic acids (sinapic acid (SiA), FA, SA), flavonoids (quercetin (QUE), kaempferol (KAE)), and antioxidant activity were investigated in salt-stressed and phenolic acid-treated plants compared with the corresponding controls. Salt stress caused a significant increase in SA and proline contents, a decrease in phenolic compounds, antioxidant activity, and photosynthetic performance, especially due to the impairment of PSI function. SA and FA treatments, with a concentration of 10 μM, had attenuated effects on salt-stressed plants, causing a decrease in proline and SA level, and indicating that the plants suffered less metabolic disturbance. Polyphenolic compounds, especially FA, SiA, KAE, and QUE, were increased in FA and SA treatments in salt-stressed plants. Consequently, antioxidant activities were increased, and photosynthetic performances were improved. FA resulted in a better ameliorative effect on salt stress compared to SA.

Highlights

Global warming and current climate changes are serious threats to agricultural production and biodiversity worldwide [1]
Salt stress is one of the most damaging for plants because it is a complex stress consisting of ionic stress caused by toxic ion concentrations, osmotic stress caused by the associated decreased water uptake, and oxidative stress caused by the increase in reactive oxygen species levels (ROS) [2]
One-month-old plantlets of Chinese cabbage were foliar-treated by a spray applicator with ferulic acid (FA) and salicylic acid (SA) in the concentration range of 10–100 μM, approximately 0.5 mL per plant per treatment, and their effects were investigated under NaCl stress conditions (150 mM, in the time period of 72 h) compared to untreated controls

Summary

Introduction

Global warming and current climate changes are serious threats to agricultural production and biodiversity worldwide [1]. Increased soil salinity is caused by natural processes (such as mineral weathering or by the gradual retreat of an ocean) and by various human activities mainly related to agricultural practices (especially soil irrigation, fertilization, etc.). 6% of all land areas are affected by salt, with about 22% of cultivated fields and 33% of irrigated fields used for agriculture. Salinity stress causes disturbances in physiological, biochemical, and metabolic processes important for plant growth and development. It can alter gene transcription, primary and secondary metabolism, cause an increase in ROS level, affect ion homeostasis, damage photosynthetic apparatus and reduce photosynthetic output, alter membrane permeability, inhibit growth and biomass accumulation, and leads to a significant reduction in crop yield [4]

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