Foliar Application of Zn Alleviates Salt Stress Symptoms of Pak Choi Plants by Activating Water Relations and Glucosinolate Synthesis

Hamideh Fatemi,Juan José Rios,Micaela Carvajal

doi:10.3390/agronomy10101528

Hamideh Fatemi, Juan José Rios + Show 1 more

Open Access

https://doi.org/10.3390/agronomy10101528

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Abstract

Several studies have related the application of micronutrients such as zinc, iron and molybdenum with alleviation of stress symptoms in horticultural plants. However, there are few studies that correlate the microelements with water relations. The main objective of this study was to determine the effect of the foliar application of Zn on pak choi (Brassica campestris, L.) plants grown under saline conditions. When plants were grown in a nutrient solution containing 0 or 80 mM NaCl, shoot biomass was greatly decreased, while, in a separate experiment, Zn toxicity was observed when it was applied at concentrations above 50 µM as a foliar spray. In a third experiment, low Zn applications, mainly 25 µM, enhanced parameters such as gas exchange, biomass and glucosinolates synthesis in plants grown under saline conditions (80 mM NaCl). Also, Zn application provoked a rise in membrane integrity and decreased oxidative damage in root cells. In conclusion, Zn application decreased oxidative damage and increased the content of glucosinolates, which could act as important signals to improve water uptake and transport and, as a consequence, alleviate salinity stress in pak choi plants.

Highlights

IntroductionSalinity is one of the most important stresses in the world, since it affects almost 1.5% of agricultural lands, and salt stress provokes decreases in crop production, mainly because of reduced water flow and ionic imbalance in the plants [3]
Environmental stresses have many detrimental effects on the quality and yield of crops [1,2].Salinity is one of the most important stresses in the world, since it affects almost 1.5% of agricultural lands, and salt stress provokes decreases in crop production, mainly because of reduced water flow and ionic imbalance in the plants [3]
40 mM NaCl did not produce a reduction in shoot biomass with respect to control plants, concentrations of 80 mM or higher caused a significant decrease; for instance, shoot biomass was 4.38 g dry weight per plant (DW) at 80 mM NaCl, versus 6.6 g DW for plants grown without salinity

Summary

Introduction

Salinity is one of the most important stresses in the world, since it affects almost 1.5% of agricultural lands, and salt stress provokes decreases in crop production, mainly because of reduced water flow and ionic imbalance in the plants [3]. The ion accumulation in soil decreases the water flow into roots [4]. High concentrations of sodium (Na) inside cells cause an ion imbalance, because this element is an antagonist of potassium (K) and decreases its concentration in tissues and cells [5]. Salt stress reduces the rate of photosynthesis, with the consequent decline in crop yield. Such effects explain why salinity is one of the main abiotic stresses of interest to researchers [2,5,7]

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