水氮运筹对冬小麦籽粒锌积累的调控研究

Zinc (Zn) is an important essential microelement to maintain the normal life. Zn deficiency is recognized as a serious threat to both crop production and human health globally. Currently, more than 30 percent of the world population is at risk of Zn deficiency causing severe health complications. Continuous reliance on high proportion of cereal-based foods with low amount and availability of Zn appears to be the major reason for the widespread occurrence of the Zn-deficiency problem in humans. Enrichment of cereal grains with Zn through both genetic and agronomic biofortification is, therefore, a high priority area of research, and will contribute to improving grain quality and minimizing Zn-deficiency-related health problems in human populations. Wheat is one of the major grain crops grown in China, and the grain yield and quality is directly related to food security. From 2005, we keep doing intensive research on microelement content in wheat especially Zn. We have studied the characters of Zn absorption and accumulation in wheat plants, and the difference of Zn concentration in wheat grains. Based on our research, we think that not only genetic factors but also environmental factors and their interaction affected Zn concentration in wheat grains, and the influence of environments is unallowable to be neglected. But their regulation mechanisms are still undefined. It is well known that water and nitrogen are the most important controlling measures in wheat growth, and they are directly related to grain yield and quality. How these agronomic measures affect Zn accumulation in grains during grain building? In this research, two wheat varieties which have been grown widely in Henan province were chosen as experimental materials. With field experiment and ear in Vitro culture technology, Zn concentration in grains of different spikelet and grain positions will be studied. The field experiments will be arranged by split plots design, 2 water treatments are settled in main plots and 5 nitrogen measures in secondary plots. In ear Vitro culture, detached ears will be grown in culture solution with different nitrogen content. Based on the research of grain Zn distribution characters in different times and spaces, we want to develop the mathematical model of Zn accumulation in wheat grains. Meanwhile, effects of water and nitrogen application on Zinc accumulation in grains of winter wheat will also be analyzed. From the research, we can provide theoretical bases for water and nitrogen measures efficiently in wheat growth. And it is useful to realize the sustainable development of wheat production.

锌是维持机体正常生命活动所不可缺少的必需微量元素。目前，全球有30%以上的人群表现出锌等微量元素的缺乏症状，由此导致的“隐性饥饿”日益引起关注。小麦是我国重要的粮食作物，通过遗传育种和农艺措施提高籽粒锌含量对改善籽粒营养品质、缓解人体微营养缺乏具有重要意义。近年来，我们研究了小麦植株锌吸收积累的特性及籽粒锌含量的基因型和环境差异，认为小麦籽粒锌含量除受自身遗传因素影响外，还与环境及二者互作有关，但环境因素对籽粒锌积累的调控机制尚不明确。水氮运筹是小麦栽培生产中重要的调控措施，直接关系到籽粒的产量和品质。本研究以河南省主栽小麦品种为材料，采用田间试验和离体穗培养技术，分析不同小穗位和粒位籽粒Zn含量和积累量的分布规律，建立小麦穗发育过程中籽粒Zn积累的数学模型，探讨水氮运筹模式对小麦籽粒Zn积累时空分布的影响，为高产优质高效的水氮运筹栽培技术提供理论依据，以期实现小麦生产的可持续发展。

小麦籽粒Zn含量直接关系到人们的饮食健康。为提高小麦的微营养品质，保证小麦生产的高效、安全，我们以河南省主栽小麦品种为供试材料，以田间试验和离体穗培养方法研究了小麦植株Zn吸收和籽粒Zn积累对水分和氮肥的响应，分析了籽粒Zn含量的穗粒位空间分布，以期为小麦栽培生产中高产优质高效的水氮栽培技术提供理论依据。在项目实施期间，按照项目计划书，完成了相应的研究任务。(1) 田间试验结果表明，植株Zn积累总量在三水条件下基施180 kg/ha N肥基础上追施N肥处理时较高。籽粒Zn分配比率以三水条件下底施120 kg/ha N时较高。籽粒Zn产量以三水条件下底施180 kg/ha N时较高。(2) 从空间分布来看，植株地上各部位Zn含量和积累量均随空间位置下移而降低，拔节期追氮能够调控花后各部位Zn的积累和转运。籽粒Zn产量与拔节期追氮量之间的关系可用二次曲线函数进行模拟。(3) 穗离体培养过程中，周麦18培养20d、J22培养15d和20d时，在所有氮浓度处理下均以籽粒Zn积累量较高，旗叶鞘较低。培养25d，周麦18籽粒Zn积累量高于济麦22，但在N(0.5)和N(1.5)处理下其旗叶、旗叶鞘、穗下节及穗轴+颖壳Zn积累量则低于济麦22。外源氮供给对小麦离体穗的Zn积累有促进作用，但是过高浓度的氮供应会抑制Zn积累。培养25 d，周麦18和济麦22离体穗的Zn积累量均以N(0.5)处理最高，籽粒Zn积累量分别以N(1.0)和 N(0.5)处理最高。在试验研究中，籽粒Zn积累的数学模型目前仍在完善中，增加了不同穗型品种小麦籽粒Zn积累差异的研究，以大穗型品种（兰考矮早八）籽粒Zn分配比率高达67.93%，显著高于其他品种。在本研究基础上，我们开展了低温冷害对籽粒Zn积累影响的研究，目前正在进行中。项目实施期间，目前已发表研究论文4篇，培养硕士研究生5人。