Abstract
Hydroponics need water of good quality to prepare a balanced nutrient solution that could allow plants to reach their maximum yield potential. The rising difficulties in finding water with good quality have led to the compelling necessity of identifying sustainable ways to use saline water, limiting its negative effect on crop yield and quality. The exogenous supplementation of plant growth regulators, such as gibberellic acid (GA3), can be effective in increasing plant growth and vigor, thus helping plants to better cope with salt stress. The aim of this study was to evaluate the feasibility to increase the salt tolerance of leaf lettuce and rocket grown in a floating system by adding GA3 (10−6 M) to mineral nutrient solutions (MNS) with increasing salinity (0, 10, and 20 mM NaCl). Leaf lettuce and rocket plants suffered a significant reduction of growth and yield, determined by the reduction of biomass, leaf number, and leaf area, even with moderate salt stress (10 mM NaCl). The supplementation of exogenous GA3 through the MNS allowed plants to substantially counterbalance salt stress by enhancing various morphological and physiological traits, such as biomass accumulation, leaf expansion, stomatal conductance and water and nitrogen use efficiency. The effects of salt stress and GA3 treatment varied according to the species, thus indicating that this interaction may improve salt tolerance by activating different adaptation systems.
Highlights
One of the major challenges of agricultural research is to meet the increasing food demand while protecting natural resources and improving environmental quality
The electrical conductivity (EC) and pH values of the nutrient solutions in the tubes varied during plant growth
In a previous work [24], we found that leaf lettuce and rocket grown in a floating system showed enhanced growth and quality when 10−6 M GA3 was added to the mineral nutrient solutions (MNS)
Summary
One of the major challenges of agricultural research is to meet the increasing food demand while protecting natural resources and improving environmental quality. Salinity negatively influences the germination, growth, physiology, and productivity of crop plants These negative effects may be triggered by ionic and osmotic stresses, ion toxicity, oxidative damage, and membrane instability and permeability [3,4,5,6]; salt stress can affect plant physiology, determining an increased respiration rate, changes in C and N metabolism, modification of mineral uptake and distribution, altered chlorophyll biosynthesis, and inefficiency of photosynthesis [7,8]. All these effects result in lowered yield and quality and reduced economic productivity of crops. In Biochemistry and Molecular Biology of Plant Hormones; Hooykaas, P.J.J., Hall, M.A., Libbenga, K.R., Eds.; Elsevier: Amsterdam, The Netherlands, 1999; Volume 33, pp. 3–22.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
