Physiological and Qualitative Response of Cucurbita pepo L. to Salicylic Acid under Controlled Water Stress Conditions

Vahideh Biareh,Andrea Mastinu,Hamidreza Zakerin,José Gil Teixeira Beltrão,Esmaeil Hadidi,Farid Shekari,Saeed Sayfzadeh

doi:10.3390/horticulturae8010079

Abstract

Limited water stress is one of the most important environmental stresses that affect the growth, quantity and quality of agronomic crops. This study was undertaken to investigate the effect of foliar applied salicylic acid (SA) on physiological responses, antioxidant enzymes and qualitative traits of Cucurbita pepo L. Plants exposed to water-stressed conditions in two years of field studies. Irrigation regimes at three soil matric potential levels (−0.3, −1.2 and −1.8 MPa) and SA at four levels (0.0, 0.5, 1.0 and 1.5 mg/L) were considered as main plot and sub-plots, respectively. The soil matric potential values (MPa) was measured just before irrigation. Results showed that under water stressed conditions alone, the amounts of malondialdehyde (MDA), hydrogen peroxide (H2O2) and ion leakage were higher compared with control treatment. However, spraying of SA under both water stress and non-stress conditions reduced the values of the above parameters. Water stress increased CAT, APX and GR enzymes activity. However foliar application of SA led to the decrease of CAT, APX and GR under all soil matric potential levels. The amount of carbohydrates and fatty acids increased with the intensity of water stress and SA modulated this response. By increasing SA concentration both in optimum and stress conditions, saturated fatty acids content decreased. According to our data, the SA application is an effective approach to improve pumpkin growth under water stress conditions.

Highlights

Introduction published maps and institutional affilCucurbita pepo L. (C. pepo) is an annual herbaceous plant belonging to the Cucurbitaceae family
Results, had therea was no interaction at Superoxide dismutase (SOD)), three soil levels, salicylic acid (SA), and interaction significant effect on between the year and the treatments, reported values areenzymes the average of two years all studied traits including
Foliar application of SA led to the decrease of CAT, Ascorbate peroxidase (APX), and Glutathione Reductase (GR) under

Summary

Introduction

Introduction published maps and institutional affilCucurbita pepo L. (C. pepo) is an annual herbaceous plant belonging to the Cucurbitaceae family. (C. pepo) is an annual herbaceous plant belonging to the Cucurbitaceae family. Seeds of this plant contain valuable active ingredients that play a major role in the treatment of the prostate gland and urinary tract inflammation and atherosclerosis. Consumption of these seeds increases the body’s resistance to pathogens [1]. C. pepo seeds oil has no cholesterol, and is rich in ω9, and ω6 acids, fatty acids with more than 40% oleic acid, 33.1% linoleic acid, and 14.7% palmitic acid, and is effective in relieving joint pain, especially in chronic conditions and post-menopausal bone density [2,3]. The quantity, and quality of secondary metabolites such as alkaloids, glycosides, steroids and, essential oils in medicinal plants are affected by environmental factors including drought stress, nutrition, and plant growth regulators [4,5,6,7,8,9,10,11,12,13,14]. iations.

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