Almost 7.0% of the world’s total land area is affected by salinity1, which means that more than 900 million hectares of land in the world are affected by both salinity and sodic salinity2, accounting for 20% of cultivated land and 10% of irrigated land. occupies half the area and has a higher salt content3. Salinized soil is a major problem facing Pakistan’s agriculture4,5. Of this, about 6.3 million hectares or 14% of irrigated land is currently affected by salinity6.
Abiotic stress can alter plant growth hormone response, resulting in decreased crop growth and final yield7. When plants are exposed to salt stress, the balance between reactive oxygen species (ROS) production and the quenching effect of antioxidant enzymes is disturbed, resulting in plants suffering from oxidative stress8. Plants with higher concentrations of antioxidant enzymes (both constitutive and inducible) have healthy resistance to oxidative damage, such as superoxide dismutase (SOD), guaiacol peroxidase (POD), peroxidase-catalase (CAT), ascorbate peroxidase (APOX), and glutathione reductase (GR) can enhance salt tolerance of plants under salt stress9. In addition, phytohormones have been reported to play a regulatory role in plant growth and development, programmed cell death, and survival under changing environmental conditions10. Triacontanol is a saturated primary alcohol that is a component of plant epidermal wax and has plant growth-promoting properties11,12 as well as growth-promoting properties at low concentrations13. Foliar application can significantly improve photosynthetic pigment status, solute accumulation, growth, and biomass production in plants14,15. Foliar application of triacontanol can enhance plant stress tolerance16 by regulating the activity of multiple antioxidant enzymes17, increasing the osmoprotectant content of plant leaf tissues11,18,19 and improving the uptake response of essential minerals K+ and Ca2+, but not Na+. 14 In addition, triacontanol produces more reducing sugars, soluble proteins, and amino acids under stress conditions20,21,22.
Vegetables are rich in phytochemicals and nutrients and are essential for many metabolic processes in the human body23. Vegetable production is threatened by increasing soil salinity, especially in irrigated agricultural lands, which produce 40.0% of the world’s food24. Vegetable crops such as onion, cucumber, eggplant, pepper and tomato are sensitive to salinity25, and cucumber is an important vegetable for human nutrition worldwide26. Salt stress has a significant effect on the growth rate of cucumber, however, salinity levels above 25 mM result in a yield reduction of up to 13%27,28. The detrimental effects of salinity on cucumber result in decreased plant growth and yield5,29,30. Therefore, the aim of this study was to evaluate the role of triacontanol in alleviating salt stress in cucumber genotypes and to evaluate the ability of triacontanol to promote plant growth and productivity. This information is also crucial for developing strategies suitable for saline soils. In addition, we determined the changes in ion homeostasis in cucumber genotypes under NaCl stress.
Effect of triacontanol on inorganic osmotic regulators in leaves of four cucumber genotypes under normal and salt stress.
When cucumber genotypes were sown under salt stress conditions, total fruit number and average fruit weight were significantly reduced (Fig. 4). These reductions were more pronounced in Summer Green and 20252 genotypes, while Marketmore and Green Long retained the highest fruit number and weight after salinity challenge. Foliar application of triacontanol reduced the adverse effects of salt stress and increased fruit number and weight in all genotypes evaluated. However, triacontanol-treated Marketmore produced the highest fruit number with higher average weight under stressed and controlled conditions compared to untreated plants. Summer Green and 20252 had the highest soluble solids content in cucumber fruits and performed poorly compared to Marketmore and Green Long genotypes, which had the lowest total soluble solids concentration.
Effect of triacontanol on yield of four cucumber genotypes under normal and salt stress conditions.
The optimal concentration of triacontanol was 0.8 mg/l, which allowed to mitigate the lethal effects of the studied genotypes under salt stress and non-stress conditions. However, the effect of triacontanol on Green-Long and Marketmore was more obvious. Considering the salt tolerance potential of these genotypes and the effectiveness of triacontanol in mitigating the effects of salt stress, it is possible to recommend growing these genotypes on saline soils with foliar spraying with triacontanol.
Post time: Nov-27-2024