Effects of Foliar Application of Gibberellic Acid on the Salt Tolerance of Tomato and Sweet Pepper Transplants

Abstract

Seed germination and early seedling growth are the plant growth stages most sensitive to salt stress. Thus, the availability of poor-quality brackish water can be a big limiting factor for the nursery vegetable industry. The exogenous supplementation of gibberellic acid (GA3) may promote growth and vigor and counterbalance salt stress in mature plants. This study aimed to test exogenous supplementation through foliar spray of 10−5 M GA3 for increasing salt tolerance of tomato and sweet pepper seedlings irrigated with increasing salinity (0, 25, and 50 mM NaCl during nursery growth. Tomato and sweet pepper seedlings suffered negative effects of salinity on plant height, biomass, shoot/root ratio, leaf number, leaf area, relative water content, and stomatal conductance. The foliar application of GA3 had a growth-promoting effect on the unstressed tomato and pepper seedlings and was successful in increasing salinity tolerance of tomato seedlings up to 25 mM NaCl and up to 50 mM NaCl in sweet pepper seedlings. This treatment could represent a sustainable strategy to use saline water in vegetable nurseries limiting its negative effect on seedling quality and production time.

Influence of Ecklonia maxima Extracts on Growth, Yield, and Postharvest Quality of Hydroponic Leaf Lettuce

“…The perceived quality of leafy vegetables is greatly determined by appearance and color as they affect food choice and satisfactoriness and could also impact the consumer's perception of sensory quality. Color characteristics and the way they change during storage can be influenced by preharvest [12,15,48,96,97] or postharvest [98][99][100][101][102] factors. Leafy vegetable color can be altered by browning and yellowing (chlorophyll degradation) phenomena that could negatively affect marketability [48].…”

“…Principal component analyses can be effective in unraveling the effects of several experimental factors (genetic materials, pre-and postharvest management) on yield and quality parameters of many vegetable crops, as reported in many experiments carried out on different species and growing and storage conditions [12,86,96,97,[109][110][111]. This was also the case in the present experiment since the different effects determined by the treatments with E. maxima extract on leaf lettuce plants were clearly shown by the Principal Component Analyses that outlined the various responses of leaf lettuce during growth and storage to the supplementation of different levels of seaweed extract through the nutrient solution.…”

Use of Microbial Biostimulants to Increase the Salinity Tolerance of Vegetable Transplants

“…Thus, the availability of good quality water is of paramount importance for nursery growers, but, always more often, brackish water is the only available water source in the areas where vegetable transplants are more required. In a previous study [21], we found that the salt tolerance of tomato and sweet pepper transplants could be increased with the application of gibberellic acid. In this work, we investigated the chances to enhance the salt tolerance of lettuce and tomato seedlings and produce vegetable transplants with good quality characteristics by inoculating the growth substrate with microbial biostimulants.…”

“…Hence, the rebalancing of phytohormone levels through the exogenous application of phytohormones (gibberellins, auxins, and cytokinins) has been suggested as a strategy to increase salt tolerance of vegetable crops and mitigate the negative effects of salinity [18,20]. This rebalancing can be achieved by direct supplementation of synthetic plant growth regulators through foliar or root supplementation [20,21] or by inoculating the rhizosphere with microorganisms that produce phytohormones or interact with plants, inducing hormonal changes and modifying plant hormone status [22]. The use of microbial inoculants is becoming a more widely accepted technique for improving the sustainability of intensive agriculture systems.…”

Special Issue: Feature Papers 2020

“…Miceli et al [2] showed that tomato and sweet pepper seedlings suffered negative effects of salinity on plant growth, relative water content, and stomatal conductance. However, the foliar application of GA 3 was successful in increasing salinity tolerance of tomato seedlings up to 25 mM NaCl and up to 50 mM NaCl by sweet pepper seedlings.…”