锌与氮磷钾配合喷施对小麦锌累积、分配及转移的影响

摘要

[Objectives] Combined foliar application of Zn and macronutrients (N,P or K) has been thought an effective way to fortify Zn nutrition of human.In this study,the Zn accumulation,distribution and translocation within wheat plants were investigated to clarify mechanism of N,P,and K applications to enhance Zn concentration in wheat grains.[Methods] Field experiment was conducted using wheat as materials from October 2010 to June 2014.A split plot design was used with soil N rates of 0,120 and 240 kg/hm2 as the main plot factor,and the foliar application of distilled water (CK),ZnSO4 0.3％ (Zn),ZnSO4 0.3％ plus urea 1.7％ (Zn +N),ZnSO4 0.3％ plus KH2PO4 0.2％ (Zn + P + K) and ZnSO4 0.3％ plus K2SO4 0.5％ (Zn + K) as subplot factors.By analyzing Zn concentrations in grain and vegetative tissues (leaves,glumes and stems) of wheat,the influences of combined foliar application of Zn with N,P and K on Zn distribution,and the relative contributions of Zn remobilization and post-anthesis shoot Zn uptake to grain Zn accumulation were evaluated.[Results] Under the treatments of foliar applying Zn,Zn + N,Zn + P + K and Zn + K,the Zn concentrations were increased by 2.4-7.7 folds in the leaves,2.0-4.7 folds in the glumes and 1.8-2.4 folds in grains,which were much greater than the increase in the stems (0.2-1.0 folds),compared with foliar distilled water application (CK).The increases of Zn distribution were significant in leaves and glumes.Compared with foliar Zn application alone,foliar Zn + N and Zn + K applications increased grain and leaf Zn concentrations,while foliar Zn + P + K application reduced grain and leaf Zn concentrations.Compared with foliar Zn application alone,the postanthesis shoot Zn uptake and its mobilization to grain were increased by 12 and 14 g/hm2 in foliar Zn + N application,and 44 and 32 g/hm2 in foliar Zn + K application,but decreased by 37 and 18 g/hm2 in foliar Zn + P + K application.Soil N application significantly increased the concentration and remobilization of Zn in all the wheat organs,but these increases were much lower than those of the foliar Zn treatments.The combined foliar application of Zn with N,P and K did not affect Zn distribution within wheat.The Zn recovery rates in foliar Zn+ N and Zn + K applications were higher than that in foliar Zn application alone,while that in foliar Zn + P + K application was lower.[Conclusions] The increased grain Zn concentrations in foliar Zn + N and Zn + K applications were resulted from increased post-anthsis Zn uptake and mobilization,while the decreased grain Zn concentrations in foliar Zn + P + K applications were resulted from decreased post-anthsis Zn uptake and mobilization.%[目的]在作物上喷施锌肥与目前应用较广泛的喷施大量元素肥料(氮、磷或钾肥)相配合,是解决人体锌缺乏问题的重要途径.本研究初步阐明了锌与氮、磷及钾肥配合喷施对小麦籽粒锌营养品质的影响机制,为小麦籽粒有效可行富锌方法提供理论参考.[方法]2010-2014年连续进行了4年裂区田间试验.主处理为不同氮肥用量土施(N 0、120和240 kg/hm2),副处理为喷蒸馏水(CK)、喷0.3％ ZnSO4(Zn)、喷0.3％ ZnSO4和1.7％尿素(Zn+N)、喷0.3％ ZnSO4和0.2％ KH2PO4(Zn+P+K)、喷0.3％ ZnSO4和0.5％K2SO4(Zn+K).分析测定小麦开花期地上部以及成熟期各部位(籽粒、叶片、颖壳和茎秆)锌含量,研究锌与氮、磷或钾肥配合喷施对锌在成熟期小麦各部位的分配,以及花前和花后锌分配比例及其对籽粒锌累积的表观贡献率的影响.[结果]喷施Zn、Zn+N、Zn+P+K或Zn+K处理后锌含量提升幅度以叶片最大(2.4～7.7倍),颖壳(2.0～4.7倍)和籽粒(1.8～2.4倍)次之,茎秆最小(0.2～1.0倍),锌在叶片和颖壳分配比明显提高.与单喷Zn相比,Zn+N或Zn+K处理籽粒和叶片锌含量进一步增加,而Zn+P+K处理籽粒和叶片锌含量均有所降低.与Zn处理相比,花后营养器官锌吸收量及其向籽粒的转移量在喷Zn+N时分别增加12和14 g/hm2,在喷Zn+K时增加44和32 g/hm2,但喷Zn+P+K时分别降低37和18 g/hm2.土施氮肥亦可显著增加籽粒和各营养器官锌含量,以及锌在营养器官的累积和再转移,但增幅明显低于各喷锌处理.此外,与Zn处理相比,Zn+N、Zn+P+K或Zn+K处理未进一步影响锌在小麦各部位的分配,但锌肥的回收率在Zn +N或Zn+K处理下显著提高,在Zn+P+K处理下显著降低.[结论]锌肥与氮肥或钾肥配合喷施,主要通过增加营养器官对锌的吸收及向籽粒的转移量,进一步提高籽粒锌含量,而磷锌配合喷施通过降低营养器官对锌的吸收及向籽粒的转移进而降低籽粒锌含量.