Morphological and Physiological Responses of Cotton (Gossypium hirsutum L.) Plants to Salinity

Abstract

Salinization usually plays a primary role in soil degradation, which consequently reduces agricultural productivity. In this study, the effects of salinity on growth parameters, ion, chlorophyll, and proline content, photosynthesis, antioxidant enzyme activities, and lipid peroxidation of two cotton cultivars, [CCRI-79 (salt tolerant) and Simian 3 (salt sensitive)], were evaluated. Salinity was investigated at 0 mM, 80 mM, 160 mM, and 240 mM NaCl for 7 days. Salinity induced morphological and physiological changes, including a reduction in the dry weight of leaves and roots, root length, root volume, average root diameter, chlorophyll and proline contents, net photosynthesis and stomatal conductance. In addition, salinity caused ion imbalance in plants as shown by higher Na+ and Cl− contents and lower K+, Ca2+, and Mg2+ concentrations. Ion imbalance was more pronounced in CCRI-79 than in Simian3. In the leaves and roots of the salt-tolerant cultivar CCRI-79, increasing levels of salinity increased the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR), but reduced catalase (CAT) activity. The activities of SOD, CAT, APX, and GR in the leaves and roots of CCRI-79 were higher than those in Simian 3. CAT and APX showed the greatest H2O2 scavenging activity in both leaves and roots. Moreover, CAT and APX activities in conjunction with SOD seem to play an essential protective role in the scavenging process. These results indicate that CCRI-79 has a more effective protection mechanism and mitigated oxidative stress and lipid peroxidation by maintaining higher antioxidant activities than those in Simian 3. Overall, the chlorophyll a, chlorophyll b, and Chl (a+b) contents, net photosynthetic rate and stomatal conductance, SOD, CAT, APX, and GR activities showed the most significant variation between the two cotton cultivars.

Salt priming improved salt tolerance in sweet sorghum by enhancing osmotic resistance and reducing root Na+ uptake

“…5a). In response to oxidative stress, antioxidant system is often stimulated to provide essential protection for plants, and then antioxidant capacity can be used to discriminate salt tolerance among crop varieties (Ashrafi et al 2015;Kiani-Pouya 2015;Neto et al 2006;Sairam et al 2005;Zhang et al 2014). Accordingly, it was reported that salt priming improved antioxidant protection and helped to Fig.…”

New Insights on Plant Salt Tolerance Mechanisms and Their Potential Use for Breeding

“…Consequently, rates of transpiration (i.e., water loss) and photosynthesis (CO 2 uptake) are also reduced. Indeed, in cotton plants submitted to salt stress treatments, a substantial reduction in photosynthesis has been associated with a decrease in total chlorophyll content and distortion in chlorophyll ultrastructures (Zhang L. et al, 2014). It has been also evoked that sink to source feedback inhibition would moderate the rate of photosynthesis to match the reduced demand arising from growth inhibition (Paul and Foyer, 2001).…”

Saline stress enhanced accumulation of leaf phenolics in honeysuckle ( Lonicera japonica Thunb.) without induction of oxidative stress

“…Thus, they work together to Abbreviations: APX, ascorbate peroxidase; AsA, ascorbate; CAT, catalase; ETR, electron transport rate; Fv/Fm, the maximal photochemical capacity of PSII; H 2 O 2 , hydrogen peroxide; MDA, malondialdehyde; NADPH, nicotinamide adenine dinucleotide phosphate; O 2 , superoxide anion; PAL, phenylalanine ammonia-lyase; Pn, Photosynthetic rate; PSI, photosystem I; PSII, photosystem II; ROS, reactive oxygen species; SOD, superoxide dismutase; DMR/MR 0 , the maximal photochemical capacity of PSI.limit the generation of hydroxyl radical by controlling the levels of O 2 À and H 2 O 2 . Under saline stress, plant antioxidant system is often stimulated to defense oxidative injury, and antioxidant capacity has been used as a criterion for the comparison of salt tolerance among crop cultivars (Ashrafi et al, 2015;Kiani-Pouya, 2015;Zhang et al, 2014). Phenolic compounds which are secondary metabolites have high ROS scavenging capacity, and accumulation of phenolics is commonly considered as a positive self-protection way to strengthen ROS scavenging ability in plants upon salt-induced oxidative stress (Abrol et al, 2012;Colla et al, 2013;Falleh et al, 2012;Ksouri et al, 2007;Shao et al, 2015;Zhao et al, 2015).…”