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Zinc interception and absorption in wheat spike contribute significantly to grain zinc biofortification

Naiyue Hu, Zhiqiang Gao, Wanqing Zhang, Chenghang Du, Yinghua Zhang , Zhigan Zhao, Zhimin Wang

Abstract

Context. Spike was a crucial organ for intercepting exogenous Zn at the late growth stage. The role of spike in wheat biofortification has drawn little attention from scholars. Knowledge gaps exist for the absorption and translocation of exogenous Zn by wheat. Aims. This study aims to determine the role of spikes in wheat biofortification when Zn is applied in the canopy. And the absorption, translocation of Zn applied to different wheat organs were characterized. Methods. Two field experiments and one pot experiment were conducted to investigate the response of wheat to Zn application. Key results. Zn interception rate of spike was 13% at the heading stage and 28% at the early filling stage. Grain Zn concentration was improved by 17%-33% under AFL (Apply Zn to flag leaf) and 30%-37% under AS (Apply Zn to spike). Zn absorption amount of AFL and AS accounted for 68%-90% and 88%-99% of Zn application rate, respectively. Zn applied at the heading stage was translocated to the rest of plants before anthesis, and then to spikes. Zn applied at the early filling stage was entirely translocated to spikes. Zn translocation amount of AFL and AS accounted for 16-40% and 13%-14% of the absorbed Zn, respectively. Conclusions. Spikes are critical in intercepting and absorbing exogenous Zn. The effect of Zn absorbed by spike on grain Zn biofortification was more effective than that by flag leaf. Implications. The information generated from this study could assist in understanding how wheat plants intercept, absorb and translocate Zn.

CP23170  Accepted 19 April 2024

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