Department of Botany, Panjab University, Chandigarh, 160014, India.
Environ Sci Pollut Res Int. 2019 Mar;26(8):7821-7839. doi: 10.1007/s11356-019-04256-5. Epub 2019 Jan 24.
Arsenic (As) is the most hazardous soil contaminant, which inactivates metabolic enzymes and restrains plant growth. To withstand As stress conditions, use of some alleviative tools, such as arbuscular mycorrhizal (AM) fungi and silicon (Si), has gained importance. Therefore, the present study evaluated comparative and interactive effects of Si and arbuscular mycorrhiza-Rhizophagus irregularis on phytotoxicity of arsenate (As V) and arsenite (As III) on plant growth, ROS generation, and antioxidant defense responses in pigeonpea genotypes (Tolerant-Pusa 2002; Sensitive-Pusa 991). Roots of As III treated plants accumulated significantly higher total As than As V supplemented plants, more in Pusa 991 than Pusa 2002, which corresponded to proportionately decreased plant growth, root to biomass ratio, and oxidative burst. Although Si nutrition and AM inoculations improved plant growth by significantly reducing As uptake and the resultant oxidative burst, AM was relatively more efficient in upregulating enzymatic and non-enzymatic antioxidant defense responses as well as ascorbate-glutathione pathway when compared with Si. Pusa 2002 was more receptive to Si nourishment due to its ability to establish more efficient mycorrhizal symbiosis, which led to higher Si uptake and lower As concentrations. Moreover, +Si+AM bestowed better metalloid resistance by further reducing ROS and strengthening antioxidants. Results demonstrated that the genotype with more efficient AM symbiosis in As-contaminated soils could accrue higher benefits of Si fertilization in terms of metalloid tolerance in pigeonpea.
砷（As）是最具危害性的土壤污染物，它会使代谢酶失活并抑制植物生长。为了应对砷胁迫条件，利用一些缓解工具，如丛枝菌根（AM）真菌和硅（Si），变得尤为重要。因此，本研究评估了 Si 和丛枝菌根-粗糙球囊霉对砷酸盐（As V）和亚砷酸盐（As III）对羽扇豆基因型（耐砷-Pusa 2002；敏感-Pusa 991）植物生长、ROS 生成和抗氧化防御反应的比较和交互影响。As III 处理植物的根系比 As V 补充植物积累了更高水平的总 As，在 Pusa 991 中比 Pusa 2002 中更多，这与植物生长、根生物量比和氧化爆发相应减少有关。尽管 Si 营养和 AM 接种通过显著降低 As 吸收和由此产生的氧化爆发来改善植物生长，但与 Si 相比，AM 相对更有效地上调酶和非酶抗氧化防御反应以及抗坏血酸-谷胱甘肽途径。与 Pusa 991 相比，Pusa 2002 由于其建立更有效的菌根共生关系的能力，更容易接受 Si 营养，这导致更高的 Si 吸收和更低的 As 浓度。此外，+Si+AM 通过进一步降低 ROS 和增强抗氧化剂，赋予更好的类金属抗性。结果表明，在受 As 污染的土壤中具有更有效 AM 共生关系的基因型，在羽扇豆的类金属耐受性方面，可以从 Si 施肥中获得更高的收益。
