Watson Jean-Luc, Fang Tommy, Dimkpa Christian O, Britt David W, McLean Joan E, Jacobson Astrid, Anderson Anne J
Department of Biology, Utah State University, Logan, UT, 84322-5305, USA,
Biometals. 2015 Feb;28(1):101-12. doi: 10.1007/s10534-014-9806-8. Epub 2014 Oct 29.
Zn is an essential element for plants yet some soils are Zn-deficient and/or have low Zn-bioavailability. This paper addresses the feasibility of using ZnO nanoparticles (NPs) as soil amendments to improve Zn levels in the plant. The effects of soil properties on phytotoxicity and Zn bioavailability from the NPs were studied by using an acidic and a calcareous alkaline soil. In the acid soil, the ZnO NPs caused dose-dependent phytotoxicity, observed as inhibition of elongation of roots of wheat, Triticum aestivum. Phytotoxicity was mitigated in the calcareous alkaline soil although uptake of Zn from the ZnO NPs occurred doubling the Zn level compared to control plants. This increase occurred with a low level of Zn in the soil solution as expected from the interactions of Zn with the soil components at the alkaline pH. Soluble Zn in the acid soil was 200-fold higher and shoot levels were tenfold higher than from the alkaline soil correlating with phytotoxicity. Mitigation of toxicity was not observed in plants grown in sand amended with a commercial preparation of humic acid: growth, shoot uptake and solubility of Zn from the NPs was not altered by the humic acid. Thus, variation in humic acid between soils may not be a major factor influencing plant responses to the NPs. These findings illustrate that formulations of ZnO NPs to be used as a soil amendment would need to be tuned to soil properties to avoid phytotoxicity yet provide increased Zn accumulations in the plant.
锌是植物必需的元素，但一些土壤缺锌和/或锌的生物有效性低。本文探讨了使用氧化锌纳米颗粒（NPs）作为土壤改良剂来提高植物中锌含量的可行性。通过使用酸性土壤和石灰性碱性土壤，研究了土壤性质对纳米颗粒的植物毒性和锌生物有效性的影响。在酸性土壤中，氧化锌纳米颗粒导致剂量依赖性植物毒性，表现为抑制小麦（Triticum aestivum）根的伸长。在石灰性碱性土壤中，植物毒性得到缓解，尽管与对照植物相比，从氧化锌纳米颗粒中吸收的锌使锌含量增加了一倍。正如在碱性pH条件下锌与土壤成分相互作用所预期的那样，这种增加发生在土壤溶液中锌含量较低的情况下。酸性土壤中的可溶性锌比碱性土壤高200倍，地上部分的锌含量比碱性土壤高10倍，这与植物毒性相关。在用商业腐殖酸制剂改良的沙子中生长的植物中未观察到毒性减轻：腐殖酸未改变纳米颗粒中锌的生长、地上部分吸收和溶解度。因此，土壤间腐殖酸的差异可能不是影响植物对纳米颗粒反应的主要因素。这些发现表明，用作土壤改良剂的氧化锌纳米颗粒配方需要根据土壤性质进行调整，以避免植物毒性，同时增加植物中的锌积累。
