Agricultural and Physiological Responses of Tomato Plants Grown in Different Soilless Culture Systems with Saline Water under Greenhouse Conditions

Wilbert M Rodríguez-Ortega,Francisco García-Sánchez,J J Martinez-Nicolas,V Lidón,I Simón,J C Fernandez-Zapata,José M Cámara-Zapata,Manuel Nieves,Vicente Martínez

doi:10.1038/s41598-019-42805-7

Abstract

Tomato is the most important horticultural crop in the world. The yields for this crop are highest in Southeastern Spain. In this work we studied a commercial variety of tomato, with different soilless culture systems (deep flow technique, nutrient film technique, and the perlite substrate) and three levels of salinity (2.2, 6.3, and 10.2 dS·m−1) typical of Southeastern Spain. The irrigation management was carried out for optimizing the water use efficiency. Alterations in the water status of the plants, Cl− and Na+ toxicity, and nutritional imbalances altered the vegetative growth and physiology of the plants. The marketable yield was affected by both soilless culture system and salinity. Regarding the soilles culture system, yield decreased in the order: deep flow technique > perlite > nutrient film technique. The salinity treatments improved the fruits quality by increasing the total soluble solids and titratable acidity. Plants cultivated with the nutrient film technique had the highest concentrations of Cl− and Na+ and the highest Na+/K+ ratio. The concentrations of Cl− and Na+ in the plants were not related directly to the yield loss. Therefore, the influence of the toxicity, osmotic effect, and nutritional imbalance seems to have been responsible for the yield loss.

Highlights

Tomato plants are considered moderately sensitive to salinity[2]
The higher fruits yield derived from a greater mean fresh weight per fruit, while the number of fruits was not affected by the soilless culture system
This indicates that the fruits on plants of the variety ‘Optima’ showed low sensitivity to the different environmental conditions caused by the soilless culture systems

Summary

Introduction

Tomato plants are considered moderately sensitive to salinity[2]. The growth and yield of the crop begin to decline when the electrical conductivity (EC) of the nutrient solution (NS) with which it is cultivated exceeds www.nature.com/scientificreports/. As the time of exposure to salt increases, plants begin to suffer phytotoxicity, due to Cl− and Na+ accumulation, and nutritional imbalances, as the uptake of some nutrients is inhibited[11,12,13,14,15] These three factors will negatively influence the physiological and metabolic processes of plants - such as photosynthesis, respiration, and cell division16 - and will lead to the synthesis of reactive oxygen species, which cause a decrease in vegetative growth and yield[17]. The lack of water forces farmers to optimize irrigation management, to maximize production with the lowest water consumption In this area a new type of NFT system, called the New Growing System (NGS ©), is being commercialized, which reduces the water consumption due to the recirculation of the NS. A non-commercial hydroponic crop (deep flow technique, DFT) has been used as a control system that allows us to know the maximum potential of water use efficiency (WUEagri, kg·m−3) for this crop

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Conclusion