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

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.

Physiological, Biochemical, and Agronomic Trait Responses of Nigella sativa Genotypes to Water Stress

“…In Equation ( 2), ASW represents available soil moisture, FC represents the percentage of soil water content in the crop capacity point, PWP represents the percentage of moisture content at the permanent wilting point, P b represents soil bulk density at the root growth zone in grams per cm 3 , and V represents the experimental unit size.…”

“…Plant height was shown to decline with an increasing moisture deficit in all the genotypes, but this decrease is dependent on the genotype and irrigation regime. Drought also causes a reduction in the leaf size, stem extension, stomatal conductance, and photosynthetic rate [3,15].…”

“…Drought is widely acknowledged as one of the most limiting abiotic stresses affecting global agricultural productivity [1][2][3][4][5][6]. Climate change, insufficient and variable distribution of rainfall, population increase, and agricultural mismanagement have all contributed to water shortages, which have harmed the growth and development of crop species [2,[7][8][9][10][11][12].…”

Salicylic Acid Stimulates Defense Systems in Allium hirtifolium Grown under Water Deficit Stress

“…Drought is the most common and important environmental stress limiting the yield of many crops and medicinals, especially in arid and semi-arid regions [ 8 , 9 ], which reduces plants yield by more than 50% on average. Drought stress causes a broad range of physiological changes and impairments of metabolic processes, which result in the accumulation of reactive oxygen species (ROS) [ 10 , 11 ].…”

“…Drought stress reduces plant water potential, produces reactive oxygen species (ROS), damages cell membranes, inhibits electron transfer, destroys chloroplast and thylakoid membrane structures, and degrades and reduces photosynthetic pigments [ 9 , 11 , 12 ]. It also reduces the photosystem function and finally decreases photosynthesis [ 13 ].…”