Abstract Cowpea (Vigna unguiculata (L.) Walp.) is an important grain legume crop, mostly grown on marginal soils which hamper its productivity. Improvement of salt tolerance in cowpea is contemplated as a useful strategy to economically utilize salt-affected lands. This study was conducted to evaluate the role of seed priming and biochar application in improving salt stress tolerance in cowpea. Cowpea seeds primed with CaCl2, water, or not-primed were sown in pots having biochar or no biochar and grown under optimal (no stress) and salt stress (10 dS m-1) conditions. Salt stress hindered the seedling emergence, biomass production, and accelerated the Na+ toxicity and oxidative damage. Nevertheless, osmopriming improved the cowpea performance through early seedling emergence, increase in biomass production (80.8%), leaf area (20.1%), α-amylase activity (78.7%), chlorophyll content (48.8%), soluble sugars (49.5%) and reduced MDA content (27.3%) and total antioxidant activity (22.2%) under salt stress conditions. Biochar application improved the seedling growth and reduced the oxidative damage in cowpea plant under salt stress conditions. Osmopriming integrated with biochar application further enhanced the cowpea performance under optimal growth conditions and reduced the adverse effects of salinity stress. The combination of osmopriming and biochar application hastened the seedling emergence, seedling growth, α-amylase activity (78.7%), reduced the total antioxidant activity (12.5%) and Na accumulation (30%) under salt stress over respective control. In conclusion, biochar integrated with osmopriming improved the cowpea performance under salt stress condition through early and synchronized emergence, chlorophyll synthesis, sugar accumulation which reduced the oxidative damage and Na+ toxicity resulted in better seedling growth and biomass production.

中文翻译：

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种子引发剂和生物炭联合使用提高豇豆耐盐性

摘要 豇豆（Vigna unguiculata (L.) Walp.）是一种重要的谷物豆类作物，主要生长在边缘土壤上，阻碍了其生产力。改善豇豆的耐盐性被认为是一种经济利用受盐影响土地的有用策略。本研究旨在评估种子引发和生物炭施用在提高豇豆盐胁迫耐受性方面的作用。用 CaCl2、水或未引发的豇豆种子播种在具有生物炭或无生物炭的盆中，并在最佳（无胁迫）和盐胁迫 (10 dS m-1) 条件下生长。盐胁迫阻碍了幼苗的出苗、生物量的产生，并加速了 Na+ 的毒性和氧化损伤。尽管如此，渗透引发通过早期出苗、增加生物量产量 (80.8%)、叶面积 (20.1%)、在盐胁迫条件下，α-淀粉酶活性 (78.7%)、叶绿素含量 (48.8%)、可溶性糖 (49.5%) 和降低的 MDA 含量 (27.3%) 和总抗氧化活性 (22.2%)。应用生物炭改善了盐胁迫条件下豇豆植株的幼苗生长并减少了氧化损伤。Osmopriming 与生物炭应用相结合，进一步提高了豇豆在最佳生长条件下的性能，并减少了盐分胁迫的不利影响。与相应对照相比，渗透引发和生物炭施用相结合加速了幼苗的出苗、幼苗生长、α-淀粉酶活性（78.7%），降低了盐胁迫下的总抗氧化活性（12.5%）和钠积累（30%）。综上所述，