Alpha-Tocopherol Induced Modulations in Morpho-Physiological Attributes of Sunflower (Helianthus annuus) Grown under Saline Environment

Abstract

Among abiotic stresses salinity is one of the serious threats for food security worldwide. Sunflower is ranked 5 th among crops grown for food security and being moderately salt tolerant is a better choice for growing on saline soil. Application of various compounds including vitamin E might be a beneficial technique for improving growth in plants under saline conditions. A pot experiment was conducted to explore the role of alpha tocopherol seed treatment for inducing salt tolerance in sunflower. Seeds of two sunflower cultivars (FH-572 and FH-621) were soaked for 16 h in four levels of alpha tocopherol i.e. control (distilled water), 100, 200, 300 mg L-1 and two levels of NaCl salt (0 and 120 mM) were applied with full strength Hoagland's solution 35 days after seed sowing. Salt stress caused significant decrease in shoot and root fresh weight, leaf relative water content and inhibition in shoot length. Salinity stress increased leaf turgor potential and had non-significant effect on photosynthetic pigments, osmotic potential and gas exchange characteristics. Seed treatment with α-tocopherol considerably increased shoot and root fresh weight, shoot length, net CO2 assimilation rate, stomatal conductance (gs) and water use efficiency; however, it showed non-significant effect on photosynthetic pigments, leaf water relation parameters and transpiration rate. Alpha tocopherol, 100 and 300 mg L-1 levels were effective in ameliorating the negative impact of salt stress in cv. FH-572 and cv. FH-621, respectively. Results depicts great varietal difference in salinity tolerance and cultivar FH-621 performed better than cv. FH-572 under salinity stress.

Presowing seed treatment with glycine betaine confers NaCl tolerance in quinoa by modulating some physiological processes and antioxidant machinery

“…Ames-13737 and PI-634919 (Table 1, Figure 1). These results follow the results of previous studies in many crops like wheat (Kausar and Shahbaz, 2017) and sunflower (Lalarukh and Shahbaz, 2018), and this reduction is credited to excessive ROS production and metabolic disorders produced under stress condition. Ion toxicity and higher osmotic stress is another reason which might be responsible for reduction in growth parameters (Hasanuzzaman et al, 2013).…”

“…Accumulation of salts changes different physiological mechanisms like gas exchange parameters and chlorophyll fluorescence in crop plants (Shahbaz et al, 2017). Salinity also disturbs the numerous metabolic processes especially CO 2 assimilation rate and reduces the growth in rice (Shahbaz and Zia, 2011) and sunflower (Lalarukh and Shahbaz, 2018). Salinity is a major factor that reduces plant development and yield (Shahbaz et al, 2017;Lalarukh and Shahbaz, 2018).…”

“…Accumulation of salts changes different physiological mechanisms like gas exchange parameters and chlorophyll fluorescence in crop plants (Shahbaz et al, 2017). Salinity also disturbs the numerous metabolic processes especially CO 2 assimilation rate and reduces the growth in rice (Shahbaz and Zia, 2011) and sunflower (Lalarukh and Shahbaz, 2018). Salinity is a major factor that reduces plant development and yield (Shahbaz et al, 2017;Lalarukh and Shahbaz, 2018).Oxidative stress generated due to excessive production of reactive oxygen species (ROS) leads to the upregulation of defensive mechanism in plants, i.e., enzymatic (catalase, superoxide dismutase and peroxidase) as well as nonenzymatic (ascorbate, tocopherol and phenolics) antioxidants (Shafiq et al, 2015).…”

Abiotic Stress in Crop Species: Improving Tolerance by Applying Plant Metabolites

“…The time of application also influences the effects of α-Toc on plant development. Lalarukh et al [108] treated seeds of two sunflower (Helianthus annuus) varieties with different α-Toc concentrations and grew them in pots under NaCl treatment. Given that sunflower is moderately tolerant to salt stress, it is a good candidate for growing in saline soils.…”

Alpha Tocopherol Application as Seed Priming Alters Antioxidative Defense System of Okra Against Salinity Stress

“…Additionally, upregulation of non-enzymatic antioxidants under oxidative stress quench ROS [8]. Priming with antioxidants is a pragmatic approach to combat salinity induced oxidative stress [9], that allows pre-germination metabolism [10]. Salinity tolerance is linked with improved sugars metabolism [6].…”