Cowpea is a highly nutritious grain legume crop, cultivated mostly in a semi-arid environment and frequently confronts sporadic dry periods during different stages of plant growth, which drastically reduce its productivity. The current study was enacted to evaluate the biochar application and seed priming induced drought tolerance in cowpea. The seeds of cowpea were primed with CaCl2 (1% solution), water (hydropriming) (positive control), and dry seeds (absolute control), sown in pots with and without mango wood biochar. The water holding capacity (WHC) in well-watered and drought-stressed pots was maintained at 70% and 35%, respectively. Drought stress caused a delay in germination and reduced plant growth. Osmopriming enhanced seed germination, seedling growth, dry biomass production, chlorophyll contents, leaf area, soluble sugar contents, CO2 assimilation, water use efficiency (WUE), and leaf K+ concentration and inhibited the oxidative damage in cowpea under drought. The addition of biochar was effectively recuperated by the drought-induced growth reduction in cowpea. Osmopriming + biochar application increased the biomass production (115%), α-amylase activity (81%), chlorophyll contents (76%), total soluble sugars (60%), WUE (95%), leaf osmotic potential (25%), and leaf sap K + concentration (25%), and decreased the MDA content and total antioxidant activity by 34 and 28%, respectively, than non-primed control without biochar application under drought. Osmopriming supplemented with biochar amendment augmented the performance of cowpea under normal and water-deficit conditions through synchronized seedling emergence and better growth, chlorophyll synthesis, CO2 assimilation, osmolyte accumulation, and nutrient uptake with minimal oxidative damage, which lead to better cowpea performance in drought stress condition. Osmopriming and biochar application may prove effective in improving cowpea performance under changing climate.

中文翻译：

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种子引发和生物炭应用的结合提高了豇豆的耐旱性

豇豆是一种营养丰富的豆类作物，主要种植在半干旱环境中，在植物生长的不同阶段经常面临零星的干旱期，这大大降低了其生产力。目前的研究旨在评估豇豆的生物炭应用和种子引发引起的耐旱性。豇豆种子用 CaCl2（1% 溶液）、水（水浸）（阳性对照）和干种子（绝对对照）处理，播种在有或没有芒果木生物炭的盆中。浇水充足和干旱胁迫的盆的持水能力（WHC）分别保持在 70% 和 35%。干旱胁迫导致发芽延迟和植物生长减少。Osmopriming 增强种子发芽、幼苗生长、干生物量生产、叶绿素含量、叶面积、可溶性糖含量、CO2 同化、水分利用效率 (WUE) 和叶片 K+ 浓度并抑制干旱条件下豇豆的氧化损伤。干旱引起的豇豆生长减少有效地恢复了生物炭的添加。Osmopriming + biochar 应用增加了生物量产量 (115%)、α-淀粉酶活性 (81%)、叶绿素含量 (76%)、总可溶性糖 (60%)、WUE (95%)、叶渗透势 (25%)和叶液 K + 浓度 (25%)，在干旱条件下，与未施涂生物炭的未引发对照相比，MDA 含量和总抗氧化活性分别降低了 34% 和 28%。Osmopriming 补充 biochar 修正通过同步出苗和更好的生长、叶绿素合成、CO2 同化，在正常和缺水条件下增强了豇豆的性能。渗透物积累和养分吸收，氧化损伤最小，这导致豇豆在干旱胁迫条件下表现更好。Osmopriming 和 biochar 应用可能被证明可以有效提高气候变化下豇豆的性能。