The study was conducted to investigate the effects of foliar-intervention of nano-TiO2 on Cd toxicity in cowpea plants. Cowpea plants were exposed to Cd toxicity at 10 mg/kg soil for 21 days and afterwards, subjected to six episodes of foliar application of nano-TiO2 intervention. Results showed that foliar-applied nano-TiO2 significantly promoted chlorophyll b and total chlorophyll contents after Cd stress as compared to Cd-stressed plants without the intervention. Interestingly, Cd contents of roots, shoots and grains were significantly reduced (p < 0.05) after nano-TiO2 sprays compared to Cd-stressed plants. However, the Cd contents in edible tissues (leaves and seeds) after interventions remained above recommended threshold. Furthermore, nano-TiO2 interventions promoted stress enzymes activity in both roots and leaves as well as increased Zn, Mn and Co levels in seeds compared to Cd-stressed plants without intervention. Estimated daily intake of Cd in leaves and seeds for adult subpopulation exceeded the WHO recommended daily intake by some folds in Cd-stressed and nano-TiO2-treated plants. The health risk quotient (HQ) for adult subpopulation exceeded unitary in seeds from nano-TiO2 treatments (HQ = 1.75 and 1.96, respectively) while no potential risk was obtained for leaves. Overall, foliar application of nano-TiO2 portends significant ameliorative potential for Cd toxicity in cowpea plants.

中文翻译：

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cow豆植物中的镉毒性：纳米TiO2的叶面干预对组织Cd生物积累，应激酶和潜在饮食健康风险的影响。

进行该研究以研究叶面干预纳米TiO2对cow豆植物中Cd毒性的影响。pea豆植物在10 mg / kg的土壤中暴露于Cd毒性下达21天，然后进行六次叶面纳米TiO2干预。结果表明，与无干预措施的镉胁迫植物相比，叶面施用的纳米TiO2显着促进了镉胁迫后的叶片叶绿素b和总叶绿素含量。有趣的是，与镉胁迫的植物相比，纳米TiO2喷雾后根，茎和谷物中的镉含量显着降低（p <0.05）。但是，干预后可食组织（叶子和种子）中的镉含量仍高于建议的阈值。此外，与未经干预的镉胁迫植物相比，纳米TiO2干预促进了根和叶的胁迫酶活性，并增加了种子中锌，锰和钴的含量。成年亚群的叶片和种子中估计的每日Cd摄入量超出了WHO建议的Cd胁迫和纳米TiO2处理植物的每日摄入量。在纳米TiO2处理的种子中，成年亚群的健康风险商（HQ）超过了单一值（分别为HQ = 1.75和1.96），而未发现潜在的叶子风险。总体而言，纳米TiO2的叶面施用预示着cow豆植物中镉毒性的显着改善潜力。成年亚群的叶片和种子中每日估计的Cd摄入量超出了WHO建议的Cd胁迫和纳米TiO2处理植物的每日摄入量。在纳米TiO2处理的种子中，成年亚群的健康风险商（HQ）超过了单一值（分别为HQ = 1.75和1.96），而未发现潜在的叶子风险。总体而言，纳米TiO2的叶面施用预示着cow豆植物中镉毒性的显着改善潜力。成年亚群的叶片和种子中估计的每日Cd摄入量超出了WHO建议的Cd胁迫和纳米TiO2处理植物的每日摄入量。在纳米TiO2处理的种子中，成年亚群的健康风险商（HQ）超过了整数（分别为HQ = 1.75和1.96），而没有潜在的叶子风险。总体而言，纳米TiO2的叶面施用预示着cow豆植物中镉毒性的显着改善潜力。