Department of Soil Science, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan 60800, Pakistan.
Department of Soil Science, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan 60800, Pakistan.
Sci Total Environ. 2019 Mar 1;654:402-408. doi: 10.1016/j.scitotenv.2018.11.097. Epub 2018 Nov 8.
Zinc (Zn)-biofortified wheat may contribute to decreasing widespread human Zn deficiency. Such genotypes may also accumulate cadmium (Cd) in grains that would expect to be decreased by Zn application. However, the influence of soil and foliar Zn application on grain Cd accumulation in Zn-biofortified versus standard wheat is unknown. In our experiment, we grew standard (Faisalabad-2008) and Zn-biofortified (Zincol-2016) wheats in pots having uncontaminated (T) or Cd-spiked (8 mg kg) soil. Plants in Cd-amended pots were treated with no Zn (T), 8 mg Zn kg to soil at sowing (T), 0.5% w/v ZnSO·7HO to foliage at booting and heading (T), or soil (as in T) + foliar (as in T) Zn application (T). Only in the uncontaminated control, grain yield of Faisalabad-2008 was greater than Zincol-2016. Any Zn application to Zincol-2016 grown in Cd-spiked pots increased grain yield compared with the uncontaminated control. In both cultivars, grain Zn concentration was influenced more by foliar than soil Zn application. However, Zincol-2016 had 6 to 14 mg more Zn kg in grains than Faisalabad-2008 in the comparable treatments. Cadmium exposure (T vs. T) decreased grain yield of only Faisalabad-2008, and decreased grain Zn concentration only in Zincol-2016. Without any Zn application, grain Cd concentration in both cultivars exposed to Cd was above the permissible level (0.20 mg kg). Zinc application decreased grain Cd concentration, although it remained above the permissible level in both cultivars except in Faisalabad-2008 when treated with soil + foliar Zn. Foliar Zn application decreased grain Cd concentration more than soil Zn application, and more in Zincol-2016 than Faisalabad-2008. In the comparable Cd-spiked treatments, Zincol-2016 had 73 to 134% higher grain Cd concentration than Faisalabad-2008. The Zn-biofortified genotypes accumulating toxic metals may pose serious health issues. Therefore, future breeding for biofortification should focus on the selective accumulation of Zn.
锌（Zn）-生物强化小麦可能有助于减少广泛存在的人类锌缺乏症。此类基因型在籽粒中也可能积累镉（Cd），而通过施用锌可以减少这种情况。然而，土壤和叶面施锌对生物强化和标准小麦籽粒中 Cd 积累的影响尚不清楚。在我们的实验中，我们在未受污染（T）或 Cd 污染（8mg/kg）的土壤中种植了标准（Faisalabad-2008）和生物强化（Zincol-2016）小麦。在 Cd 处理的盆中，植物未施锌（T）、播种时土壤施 8mg/kg Zn（T）、拔节和抽穗时叶面喷施 0.5% w/v ZnSO·7HO（T）或土壤（T）+叶面（T）施锌。只有在未受污染的对照中，Faisalabad-2008 的籽粒产量才大于 Zincol-2016。与未受污染的对照相比，向 Zincol-2016 生长的 Cd 污染盆中施用任何 Zn 都会增加籽粒产量。在两种品种中，叶面 Zn 处理比土壤 Zn 处理更能影响籽粒 Zn 浓度。然而，在可比处理中，Zincol-2016 的籽粒中 Zn 含量比 Faisalabad-2008 多 6 至 14mg/kg。暴露于 Cd（T 与 T）仅降低了 Faisalabad-2008 的籽粒产量，并且仅降低了 Zincol-2016 的籽粒 Zn 浓度。在没有任何 Zn 施用的情况下，两种品种暴露于 Cd 的籽粒 Cd 浓度均高于允许水平（0.20mg/kg）。施用 Zn 虽然降低了两种品种的籽粒 Cd 浓度，但除了用土壤+叶面 Zn 处理的 Faisalabad-2008 之外，所有处理均高于允许水平。叶面 Zn 处理比土壤 Zn 处理更能降低籽粒 Cd 浓度，并且在 Zincol-2016 中比在 Faisalabad-2008 中更为显著。在可比的 Cd 污染处理中，Zincol-2016 的籽粒 Cd 浓度比 Faisalabad-2008 高 73%至 134%。积累有毒金属的生物强化基因型可能会造成严重的健康问题。因此，未来的生物强化育种应侧重于选择性积累 Zn。
