Effect of Gibberellic Acid on Growth, Yield, and Quality of Leaf Lettuce and Rocket Grown in a Floating System

Abstract

Gibberellins (GAs) are growth hormones strongly involved in a wide variety of physiological activities. Currently, gibberellins are commercially used to enhance phenotypic characteristics, earliness, and productivity of many vegetable and ornamental crops. In this work, the efficacy of supplementation of low levels of gibberellic acid (0, 10−8, 10−6, and 10−4 M GA3) through the mineral nutrient solution of a floating system on yield and quality of leaf lettuce and rocket plants was tested. The marketability of plants was lost when 10−4 M GA3 was added to the mineral nutrient solution. This study demonstrated that the addition of 10−4 M GA3 exceeded the acceptable threshold for use in hydroponics production systems. Below the concentration of 10−4 M, the presence of GA3 in the mineral nutrient solutions (MNS), especially at 10−6 M GA3, stimulated plant growth and enhanced the yield. Various morphological and physiological traits were enhanced by GA3 treatments (biomass accumulation, leaf expansion, stomatal conductance, water use efficiency (WUE), Nitrogen use efficiency (NUE), etc.), with superimposable trends in both lettuce and rocket. The addition of 10−6 M GA3 to the nutrient solution of a hydroponic floating system can promote growth and quality of lettuce and rocket plants.

Use of Gibberellic Acid to Increase the Salt Tolerance of Leaf Lettuce and Rocket Grown in a Floating System

“…Crispa) and rocket (Eruca sativa L.). Six treatments derived from a factorial combination of three NaCl concentrations (0, 10, and 20 mM NaCl) and two GA 3 concentrations (0 and 10 −6 M GA 3 [24,32]; Gibrelex, Biolchim, Bologna, Italy) were tested for each species.…”

“…Among these PGRs, gibberellins (GAs) are essential endogenous hormones produced by plants and fungi that control plant development by triggering several physiological mechanisms [23,24]. The response of plant tissue to the GA signal can be the modification in gene expression, plant physiology, and morphology [25].…”

“…Yet, studies on the effects of gibberellic acid application on leafy vegetables grown in hydroponics are rather scant. Miceli et al [24,32] found that the supplementation of 10 −6 M GA 3 through the nutrient solution of hydroponically grown leaf lettuce and rocket can exert a significant effect on the yield, quality, and post-harvest life of these vegetables. Thus, the exogenous application of GA 3 trough the nutrient solution could also affect the salt tolerance of leafy vegetables.…”

Effect of Agronomic Practices on Yield and Quality of Borage at Harvest and During Storage as Minimally-Processed Produce

“…As reported by others authors for various leafy vegetables [26,[35][36][37][38][39], minimally-processed vegetables packed in sealed plastic bags characterized by low permeability to water vapor do not suffer dehydration due to the very high Consumer's perception of vegetable quality is mainly influenced by their color and appearance; thus, color modifications and overall appearance are the primary parameters for the quality evaluation of vegetables, especially those minimally-processed [44,48]. These modifications may occur due to both pre-harvest [48][49][50][51][52] or post-harvest [17,19,[35][36][37]53,54] factors. The color variability of borage leaves was mainly due to the difference between the tested borage accessions as already reported for chlorophyll content; accession H had leaves more yellowish (higher a* values) and greenish (higher b* values), resulting in a more vivid color (chroma) than accession D4 (Table 4).…”

Autotoxicity in Strawberry Under Recycled Hydroponics and Its Mitigation Methods

“…It is known that auxin controls several fundamental functions in plant development processes such as cell expansion and division, lateral root formation, vascular differentiation, and shoot elongation (Lomax et al, 1995;Hobbie, 1998;Berleth and Sachs, 2001). In deep water culture, various morphological and physiological traits such as biomass accumulation, leaf expansion, stomatal conductance, water use efficiency, and the nitrogen use efficiency of leaf lettuce and rocket, were found to be enhanced by 10 −6 M GA 3 addition to the nutrient solution (Miceli et al, 2019). In another study, it was reported that Si significantly enhanced the α-amylase activity and gene expression in melon seeds under autotoxicity, and promoted the degradation of starch.…”