品种和养分管理影响冬小麦籽粒锌营养

Wheat grain zinc nutrition as affected by cultivar and nutrient management

【目的】小麦籽粒中的锌含量对人类锌营养具有重要影响,研究品种特性、磷肥和丛枝菌根真菌(Arbuscular mycorrhizal fungal,AMF)对小麦籽粒锌含量的影响,为通过选择基因型育种和绿色养分管理最大化小麦锌营养提供理论依据。【方法】开展盆栽试验,供试小麦品种包括育成年代为1940s的蚂蚱麦(MZ)、1950s的碧蚂1号(BM)、1960s的丰产3号(FC)和2010s的长旱58号(CH),每个品种设置两个磷肥处理:施磷200 mg/kg(HP)和不施磷(LP);两个接菌处理:接种60 g Rhizophagus intraradices菌剂(A)和未接种(CK),每个品种均包括4个处理。在小麦开花期和成熟期,测定各部位锌含量和植株生物量、产量,分析菌根侵染率,计算菌根生长以及与菌根生长相关联的磷、锌吸收响应值(MGR、MPR、MZnR),以偏最小二乘路径模型分析锌吸收相关指标对籽粒锌含量的效应。【结果】冬小麦不同品种间籽粒产量存在显著差异,随品种的更替籽粒产量显著增加,而籽粒锌浓度随品种的更替呈降低趋势。HP-CK处理冬小麦籽粒产量较LP-CK处理显著增加36.73%~42.16%,籽粒锌浓度显著降低11.57%~27.07%,FC、CH的籽粒锌累积量分别显著增加25.75%、14.44%。LP�A处理下4个冬小麦品种的根系菌根侵染率存在显著差异;施磷显著降低了冬小麦菌根侵染率(13.04%~23.63%)且导致品种间菌根侵染率无显著差异。与LP-CK处理相比,LP-A处理冬小麦籽粒锌浓度增加6.78%~9.37%,累积量显著提高23.75%~29.79%;HP-A处理仅CH的籽粒锌累积量较HP-CK处理显著提高。磷肥施用显著降低了4个冬小麦品种的MPR值(99.29%~140.76%),BM、FC和CH的MGR值(68.22%~71.77%)和MZnR值(56.47%~67.18%)。偏最小二乘路径分析结果显示,品种对籽粒锌浓度变化影响最大(−0.656),其次是磷肥(−0.557)、产量(−0.456)和AMF(0.191)。现代品种CH始终表现出较低的籽粒锌浓度和更高的产量及籽粒锌累积量。【结论】品种的产量潜力和养分管理是影响籽粒锌浓度最重要的因素。相比于育成年代较早的品种,当代品种小麦产量潜力高,对施肥(磷肥)和接种AMF的反应也高于育成年代较早的品种,因而进一步加剧了锌含量的稀释效应。因此,当代小麦品种需特别注意补充锌肥,以缓解稀释效应带来的籽粒低锌营养。

【Objectives】Wheat grain Zn content plays important roles for ensuring human Zn nutrition.We studied the influence factors causing the low grain Zn content,to provide reference for maximizing wheat Zn nutrition through breeding and nutrient management.The function of arbuscular mycorrhizal fungi(AMF)is one of the important ways to improve agricultural sustainability.【Methods】Pot culture method was used in this study.The four winter wheat cultivars were bred in different decades:Mazha in 1940s(MZ),Bima 1 in 1950s(BM),Fengchan 3 in 1960s(FC),and Changhan 58 in 2010s(CH).For each cultivar,two phosphorus treatments were set up as no P application and applying P 200 mg/kg;and two inoculation treatments as:without inoculation(CK)and inoculation of 60 g Rhizophagus intraradices(A).At pre-and post-anthesis stages,the wheat plant biomass,yield,and root mycorrhizal infection rate were investigated,the Zn contents in plant and grains were analyzed,the responsiveness of mycorrhizal growth(MGR),shoot zinc uptake(MZnR)and P uptake(MPR)of each cultivar were then calculated,and the importance of zinc absorption related traits was determined for the grain Zn content using the partial least squares path analysis(PLS-PM).【Results】The grain yield differed significantly among cultivars under different treatments and the grain yield increased significantly with the replacement of cultivars,while the grain zinc concentration decreased with the replacement of cultivars.Compared with LP-CK treatment,the HP-CK treatment increased the grain yield by 36.73%−42.16%,significantly reduced the grain Zn concentration by 11.57%−27.07%,and the Zn accumulation of FC and CH increased by 25.75%and 14.44%,respectively.The mycorrhizal colonization rates differed significantly among cultivars under LP-A treatment,but the differences lost and the colonization rates declined under HP-A.Compared with LP-CK treatment,the LP-A treatment increased grain Zn concentration by 6.78%−9.37%,and the Zn accumulation increased by 23.75%−29.79%.While only the grain zinc accumulation of CH in HP-A treatment was significantly higher than that in HP-CK treatment.P application significantly reduced MPR of all the cultivars by 99.29%−140.76%,reduced the MZnR,MGR of BM,FC and CH by 56.47%−67.18%,68.22%−71.77%,respectively.The results PLS-PM showed that the cultivar had the greatest effect on the grain zinc concentration(−0.656),followed by phosphate fertilizer(−0.557),yield(−0.456)and AMF(0.191).The modern cultivar CH always showed lower grain zinc concentration and higher grain zinc accumulation.【Conclusions】The yield potential of cultivar and nutrient management are the most important factors deciding the wheat grain Zn content.High yield produces dilution effect,and the fertilization will exaggerate the dilution effect.AMF inoculation shows a certain effect on the Zn uptake,but the effect will be offset greatly by fertilization.Therefore,Zn fertilization should be paid attention in modern wheat cultivars.