Use of innovative electronic technology of Nanobubbles generator for growing lettuce (Lactuca sativa L.) under high salinity irrigation water management, in floating disks hydroponic systems

Abstract

Hydroponically grown plants are growing in the market and represents a sustainable way for food production. New technologies emerge and provide more efficient solutions for hydroponics. Solution to high salinity irrigation water deserves more research, since the increase in water salinity is a world issue. Studies in growing leafy vegetable under high salinity conditions do not exist. The present study was set out to determine how the employment of a hydroponic technology (floating discs) in a greenhouse with a Nanobubbles generator affected the morphological and physiological responses of lettuce (Lactuca sativa l.) to salt stress. The seedlings were exposed to NaCL solutions at ten concentrations of electrical conductivity (ECi) for three weeks. These concentrations/treatments include a Control value of ECi<1dS/m as Control and ECis of 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20dS/m. Once a week, throughout the salt stress, morphological features were evaluated. Final measurements were gathered when the experiment was completed. Two different varieties of lettuce have been employed: Cos lettuce and green leaf lettuce. During the experiment, the ambient temperature and relative humidity, the temperature of the nutrient solutions and conductivity in the containers, and the dissolved oxygen and pH of the solutions were measured. In addition, greenhouse environment CO2, fluorescence, light, nitrates, and nutrients were measured and recorded in the present work's corresponding tables. The lettuces had survived - commercially- under high salinity irrigation water. Nanobubbles (NBs) in hydroponics for oxygenating plant roots of both lettuce varieties, have affected positively their growth (fresh green weight, roots and lengths) under a variety of ECi (high salinity of irrigation water).The NB device was proven to be a innovative technology for sustainable lettuce production under the specific hydroponic system. It is recommended to become part of any innovative hydroponic system and under high salinity irrigation water. This device presents a valuable solution to the world issue of increased salinity of irrigation water.