Unraveling the Modulation of Controlled Salinity Stress on Morphometric Traits, Mineral Profile, and Bioactive Metabolome Equilibrium in Hydroponic Basil

Abstract

Salinity is a major concern in several ecosystems and has a significant impact on global agriculture. To increase the sustainability of horticultural food systems, better management and usage of saline water and soils need to be supported by knowledge of the crop-specific responses to tolerable levels of salinity. The aim of this work was to study the effects of mild salinity on morphological growth and development, leaf color, mineral composition, antioxidant activities, and phenolic profile of sweet basil (Ocimum basilicum L.). Plants grew in hydroponics and were exposed to three nutrient solutions (NSs) differing in the NaCl concentration (either 0, 20, or 40 mM). Inhibitory effects on leaf area, fresh yield, and shoot biomass were evident starting from the lowest NaCl concentration, and they became more severe and wide-ranging at 40 mM, also affecting height and root-to-shoot ratio. Salinity increased the nutritional quality in terms of antioxidant activity and polyphenols in leaves, with a reduction in macroelements at 40 mM NaCl. Moreover, the two mild NaCl concentrations specifically modified the concentration of various phenolic acids in leaves. Overall, the use of a slightly saline (20 mM) NS could be tolerated by basil in hydroponics, strongly ameliorating the nutritional profile in the face of relative yield loss. Considering the significantly higher accumulation of bioactive compounds, our work implies that the use of low-salinity water can sustainably increase the nutritional value and the health-promoting features of basil leaves.

Ameliorative effects of plant growth-promoting rhizobacteria on salinity tolerance of sweet basil (Ocimum basilicum L.)

“…Concomitant with the decrease in NR activity under salt stress, nitrate content (as a required substrate for NR activity) also decreased in basil leaves. Similar to the results of this research, previous studies have reported a reduction of nitrate in basil leaves under saline conditions (Corrado et al, 2021). The results of this study also showed that salt stress inhibited GS activity and decreased total soluble protein content, limiting nitrogen assimilation under saline conditions.…”

Managing the Product Quality of Vegetable Crops under Abiotic Stress

“…The majority of the contributions deal with pre-harvest conditions and investigate whether cultivation practices can modulate the yield and nutritional value of vegetable crops and herbs under abiotic stresses. Among these publications, several deal with nutrient supply [2][3][4][5], salinity [6,7], water supply [2,3,8] or lighting conditions [6]. Two manuscripts describe either the effects of applying chemical substances such as gibberellic acid [9] or seaweed extract [10] on the yield and quality of vegetable crops.…”

“…These crops were mostly grown in greenhouses [2][3][4], but some were grown in an open field [9] or under rain-out shelters [8]. Leafy vegetables and herbs-such as arugula [5], purslane [6] and basil [7]-were used in three experiments and were cultivated in growth cabinets [5,6] or in greenhouses [7]. The bulbs of onions were harvested from plants in a field trial [10], and the asparagus spears for a storage experiment were obtained from local farmers [12].…”

“…This was conducted by Corrado et al [7] by supplying sweet basil plants in hydroponics with three nutrient solutions with differing NaCl concentrations. Even low concentrations of NaCl (20 mM) resulted in reduced biomass development, while having positive effects on some nutritional quality parameters, such as antioxidant capacity and total polyphenols.…”

Productive, Morpho-Physiological, and Postharvest Performance of Six Basil Types Grown in a Floating Raft System: A Comparative Study

“…The need of the processing industry to obtain a product with standardized quality characteristics (i.e., color, aroma, and texture) has resulted in the gradual shift of Genovese basil cultivation from open field to protected cultivation. It is no coincidence that more than 50% of the Italian production of Genovese basil is produced in hydroponics, which guarantees high yields and better nutritional quality, as well as the deseasonalization of the production and the shortening of the production cycle [ 11 , 12 , 13 ]. Trials carried out in collaboration between researchers and producers have elected the floating raft system as the par excellence hydroponic system for the growing of Genovese basil, as it combines simplicity of management and excellent plant adaptability [ 14 ].…”