Subjects: Biology >> Botany >> Applied botany submitted time 2023-06-05 Cooperative journals: 《广西植物》
Abstract： Cerium oxide nanoparticles (CeO2NPS) have been shown to improve the salt tolerance of plant due to the potential to eliminate free radicals and the anti-oxidation properties. However, the effects and mechanisms of seed priming with CeO2NPS on pepper plant are unclear. To reveal impacts of CeO2NPS seed priming on the germination and seedling growth of peeper plants under salt stress, using the Maoshu 360 variety of pepper（Capsicum annuum）as material, a total of 7 concentrations of treatments (0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 mmol· L-1) and a control of un-treatment were carried out to investigate effects of CeO2NPS seed priming on seed germination rate, biomass, and selected physiological and biochemical indexes under salt stress. The results were as follows: (1) In the seeds primed with 0.5 mmol · L-1 cerium oxide nanoparticles, reduced levels of the superoxide anion (O2 ·−), increased activity of protein synthesis, elevated level of proline as well as increased activity of catalase (CAT), elevated content of ascorbic acid (AsA) and ratio of AsA/DHA were observed. (2)There was no loss of viability for the seeds primed with cerium oxide nanoparticles. Indeed their germination rate and germination potential were enhanced under salt stress, and their germination index, and vigor index were improved under salt stress. (3) Under salt stress, seedlings from seeds primed with 0.4 mmol·L-1 cerium oxide nanoparticles shown the highest fresh weight, dry weight, and root length; additionally, soluble protein content, ascorbic acid (AsA) content and AsA/DHA ratio were also improved. In conclusion, seed priming with CeO2NPS could enhance seed germination under salt stress by decreasing seed water potential, accelerating storage substances metabolism and improving antioxidant capacity; also, seed priming with CeO2NPS could promote seedling growth through boosting protein synthesis and ascorbic acid-glutathione cycle (AsA-GSH).
Subjects: Biology >> Botany >> Applied botany submitted time 2023-06-05 Cooperative journals: 《广西植物》
Abstract： Seed priming is proved to be an efficient way to improve crop salt tolerance, which is a measure of pre-treating seed with various agents while obtaining enhancement to crop performance at growing stage. Gamma amino butyric acid (GABA) is a non-protein amino acid involved in various metabolic processes, and partially protects plants from environmental stress. Enhancing effects of GABA priming on germination characteristics and abiotic stress have been established in several crops. However, effects and its mechanisms of GABA seed priming on salt tolerance of pepper (Capsicum annuum) are still unknown. In this study, a hybrid pepper variety of “Maoshu 360” Chaotian Pepper was used as material, the effects of seed priming with various concentrations of GABA (0 μmol·L-1, 1.0 μmol·L-1, 2.0 μmol·L-1, 4.0 μmol·L-1, 6.0 μmol·L-1, 8.0 μmol·L-1) on plant biomass, leaf osmotic regulating substance, leaf antioxidant capacity, leaf photosynthesis system, potassium and sodium uptake and distribution between leaf and shoot of pepper plants under 100 mmol·L-1 NaCl stress applied at 4-6 leaf stage were investigated. The results were as follows: (1) From the point of plant growth under salt stress, the best concentration of GABA for seed priming of pepper was 6.0 μmol·L-1, which greatly boosted the biomass of pepper plants under salt stress. (2) The mechanisms of GABA seed priming promoting salt tolerance of pepper were further analyzed. Seed priming increased the leaf contents of soluble sugar, soluble protein, chlorophyll and proline, decreased the leaf contents of ·O2 - and malondialdehyde (MDA), and enhanced the leaf activities of antioxidant enzymes, including super oxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), raised several chlorophyll fluorescence metrics, including Fv′/Fm′, qP_Lss, QY_Lss, NPQ_Lss and Rfd, reduced the K+ content and K+/Na+ ratio in roots and stems. (3) For a comprehensive understanding of the mechanisms of GABA seed priming promoting salt tolerance of pepper, a grey correlation analysis were carried out. Based on results of grey correlation analysis, seed priming with GABA significantly alleviated salt stress to pepper plants by boosting the activities of the antioxidant enzymes POD and CAT as well as increasing the levels of osmotic regulators. In conclusion, seed priming with 6.0 μmol·L-1 GABA significantly increased salt tolerance of pepper seedlings, probably by improving antioxidant and osmotic regulating capacities of pepper plants.
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