Physiological, Biochemical, and Yield Responses of Linseed (Linum usitatissimum L.) in α-Tocopherol-Mediated Alleviation of Salinity Stress

Abstract

Exogenous application of antioxidants can be helpful for plants to resist salinity, which can be a potentially simple, economical, and culturally feasible approach, compared with introgression and genetic engineering. Foliar spraying of alpha-tocopherol (α-tocopherol) is an approach to improve plant growth under salinity stress. Alpha-tocopherol acts as an antioxidant preventing salinity-induced cellular oxidation. This study was designed to investigate the negative effects of salinity (0 and 120mM NaCl) on linseed (Linum usitatissimum L.) and their alleviation by foliar spraying of α-tocopherol (0, 100, and 200mg L−1). Seeds of varieties “Chandni and Roshni” were grown in sand-filled plastic pots, laid in a completely randomized design in a factorial arrangement, and each treatment was replicated three times. Salinity significantly affected linseed morphology and yield by reducing shoot and root dry weights, photosynthetic pigment (Chl. a, Chl. b, total Chl., and carotenoids) contents, mineral ion (Ca2+, K+) uptake, and 100-seed weight. Concomitantly, salinity increased Na+, proline, soluble protein, peroxidase, catalase, and superoxide dismutase activities in both varieties. Conversely, the growth and yield of linseed varieties were significantly restored by foliar spraying of α-tocopherol under saline conditions, improving shoot and root dry matter accumulation, photosynthetic pigment, mineral ion, proline, soluble protein contents, peroxidase, catalase, superoxide dismutase activities, and 100-seed weight. Moreover, foliar spray of α-tocopherol alleviated the effects of salinity stress by reducing the Na+ concentration and enhancing K+ and Ca2+ uptake. The Chandni variety performed better than the Roshni, for all growth and physiological parameters studied. Foliar spray of α-tocopherol (200mg L−1) alleviated salinity effects by improving the antioxidant potential of linseed varieties, which ultimately restored growth and yield. Therefore, the use of α-tocopherol may enhance the productivity of linseed and other crops under saline soils.

Roles of cardiac glycosides in improving growth and productivity of salt-stressed flax plants

“…In the present investigation, the exposure of ax plants to salt stress signi cantly impaired the morphological parameters including shoot and root lengths, shoot and root fresh weights, and shoot dry weight (Table 3). These results were in accordance with those obtained by Abdullah et al (2022). Moreover, salinity reduced stomatal conductance and disrupts photosystems thus promoted the accumulation of ROS such as superoxide, hydrogen peroxide, which stimulated the oxidative degradation of chlorophyll a and b (Table 4) and enhanced membrane peroxidation as evidenced by the signi cant accumulation of malonaldehyde and causes a greater increase in electrolyte leakage (Fig.…”

Salt Tolerance of Sea Flax (Linum maritimum L.), a Rare Species with Conservation Interest in Eastern Spain

“…In L. maritimum , only low levels of Pro were detected in comparison to those reported in flaxseed [ 62 ], but another common osmolyte in plants, glycine betaine, was present in higher concentrations and showed a significant variation in response to the change in the substrate salinity, as also reported in flax [ 71 ] and Linum album , an endemic from Iran with medicinal properties [ 72 ]. However, in this latter species, the reported GB concentrations were much higher than in L. maritium or L. usitatissimum and similar to those measured in plants that are typical glycine betaine accumulators [ 73 ].…”

“…Finally, the analysis of the different ion concentrations in the roots and shoots of the salt-treated plants revealed an interesting pattern, relevant to L. maritimum ’s salt tolerance mechanisms: the Na + accumulation in the shoots was not accompanied by a decrease in K + , as observed in flax [ 62 , 68 , 83 ] and many other species. K + is an essential nutrient and the most abundant plant cation [ 84 ].…”

“…Although the EC of the substrate in the 50 mM NaCl treatment group was more than double that in the control plants, the photosynthetic pigment concentrations did not vary significantly between the two treatments. On the contrary, most reports on flax showed a significant reduction under salt stress [ 61 , 62 ] due to the inhibition of chlorophyll synthesis and the activation of its degradation with increased salinity [ 63 ].…”

“…Proline is one of the most common osmolytes in plants, which, apart from its role in osmotic adjustment, plays additional functions as an osmoprotectant, stabilising subcellular structures and macromolecules such as membranes and proteins, scavenging free radicals, and functioning as a signalling molecule in stress responses [ 65 , 66 ]. Several reports show a significant increase in proline in flax under salt stress [ 62 , 67 , 68 ], some of them indicating that the more stress-tolerant genotypes accumulate higher Pro concentrations [ 69 , 70 ], although the opposite has also been reported [ 53 ].…”