Secondary metabolites, osmolytes, and antioxidants as the primary factors boosted by salicylic acid and salicylic acid nanoparticles for white lupine growth and salinity stress tolerance
摘要
Among the primary environmental challenges is salinity, in the upcoming decades, there will be an increasing need for using salt water in agriculture. In recent years, a variety of plant bioregulators were developed using nanoparticles (NPs), a smart and potent form of material having a dual function which can both lessen the negative impacts of salinity and give plants more effective nutrient forms. This work was designed to investigate the responses of morph-physiological characteristics in white lupine to salicylic acid and its salicylic acid NPs (Sal and Sal-NPs) as foliar treatment under salt stress. Salinity with 4 gL−1 induced reductions in shoot length, number of branches and leaves per plant, shoot fresh and dry weight, while an enhancement was recorded in response to exogenous treatment with Sal (100 & 200 mgL−1) and Sal-NPs (50 & 100 mgL−1) either in the absence and presence of salinity stress. Moreover, salty water significantly decreased photosynthetic pigment constituents, endogenous indole acetic acid, and protein and carbohydrate contents. The highest amounts of chlorophyll a, chlorophyll b, carotenoids and endogenous indole acetic acid were recorded with 100 mgL−1 Sal-NPs compared to the alternative control. Total soluble sugars, proline, and soluble protein, as well as antioxidant enzymes, increased in salinity stressed plants as compared with control plants, while 100 mL−1 Sal-NPs caused more accumulation of the previously mentioned compounds. In contrast, plant oxidative stress (hydrogen peroxide, singlet oxygen and lipid peroxidation products such as malonaldehyde (MDA), lipoxygenase enzyme) were decreased in response to either Sal or Sal-NPs treatments. Secondary metabolites (phenolics and flavonoids) were accumulated in salinity stressed plants and further accumulation in response to either Sal or Sal-NPs was noticed. White lupine plants stressed with 4gL−1 salt water showed growth decline, endogenous IAA decreases that may be attributed to osmotic stress and low endogenous IAA imposed by salinity. The treatment of stressed plants with 100 and 200 mg L−1 Sal or 50 & 100 mgL−1 Sal-NPs induced an enhancement in plant growth as well as an accumulation of antioxidants, osmolytes, and secondary metabolites that could help plants overcome the negative effects of salinity.