Effect of salinity on the morphological, physiological and biochemical properties of lettuce (Lactuca sativa L.) in Bangladesh

Abstract

This study aimed to explore the changes in morphological, physiological and biochemical characteristics of lettuce (Lactuca sativa L.) in response to salt stress when grown using hydroponic techniques. The seedlings were subjected to five different concentrations (0 mM, 50 mM, 100 mM, 150 mM, and 200 mM) of NaCl for three weeks. During the salt stress, morphological properties (shoot length, root length, total plant weight, leaf number) were measured in every week. After 21 days of salt stress, physiological properties (water content and relative water content) and biochemical properties (proline, protein, phenol, reducing and non-reducing sugar content) were measured. Morphological and physiological properties were found decreased gradually with increasing salt concentrations. Biochemical properties such as proline and protein content increased remarkably, and total phenol content decreased gradually with increasing salt concentrations. Reducing sugar accumulation was higher in all treatments except 50 mM in comparison to control. Non-reducing sugar accumulation was decreased in 100 mM and 200 mM treatment, similar in 150 mM treatment, and increased in 50 mM treatment when compared to control. These findings render lettuce a salt-sensitive plant at higher salt concentration. However, changes in characteristics were realistic up to 50 mM salt concentration.

Growth, Water Relations, and Photosynthetic Activity Are Associated with Evaluating Salinity Stress Tolerance of Wheat Cultivars

“…ese damage effects induced by salt stress suppress the wheat shoot and root growth and therefore negatively affect FW and DW. Moreover, there was a progressive reduction in the wheat's FW and DW weights with increasing NaCl level, which was compatible with previous studies [1,22]. e minimum decrease in the FW and DW in Sakha69 cultivar International Journal of Agronomy might be due to the extraeffective detoxification mechanism, including the antioxidant defence mechanisms.…”

“…e notable decreases were observed with Sakha8, which was the most influenced cultivar by saline conditions, followed by Giza168 and Sakha69 which was the most resistant cultivar to the NaCl salt application. e response of plant growth to salinity stress varies among species and has been reported in many investigations [1,2,5,21,22]. In this consideration, Bacu et al [7] demonstrated that an increase in salt concentration (50, 100, and 200 mM NaCl) induced a significant decrease in the growth criteria (shoot, root, and leaf length) of five wheat cultivars.…”

“…Salinity stress is one of the major environmental issues restricting the crop growth and productivity in arid and semiarid regions. e land area influenced by salinization is continuously increasing day by day [1]. Salinity can cause oxidative stress followed by ionic toxicity and osmotic pressure at the subcellular level [2].…”

Rhizobium laguerreae Improves Productivity and Phenolic Compound Content of Lettuce (Lactuca sativa L.) under Saline Stress Conditions

“…However, studies about the effect of saline stress on the phenolic composition of lettuce have shown some conflicting results since there are diverse studies claiming increases in the phenolic composition and others that claim decreases in the levels of phenolic compounds because of saline stress. Some studies have reported that salinity can lead to non-significant changes if saline stress is low (NaCl concentration <100 mM ), or even to lower phenol index in lettuce leaves when high levels of salinity (150-1000 mM of NaCl) are used in growth media [5,36], thus, there could be a dose-dependent response. On the contrary, the results reported by Mahmoudi and co-workers [37] noted that lettuce can show different behaviors with regard to the accumulation of phenolic compounds depending not only on the lettuce variety but also on the type of salinity to which it is exposed [37].…”

“…It is traditionally consumed fresh, as in a Mediterranean diet. Lettuce stands out for its content of fiber, folate, vitamins, and bioactive compounds such as phenolic acids and flavonoids, mainly flavonols [1,2,5].…”