【作者】 曹玉贤；

【导师】 田霄鸿；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2010， 硕士

【摘要】 小麦是我国最重要的粮食作物之一,作为我国北方大部分居民的主食,是人体能量和矿质营养的主要来源。但由于小麦主要种植在我国北方大部分缺锌或潜在缺锌的石灰性土壤上,导致小麦籽粒锌缺乏现象比较普遍。此外,小麦籽粒中还含有较多能够降低锌生物有效性的化合物,其中植酸是最主要的抗营养因子。植酸是小麦籽粒中磷的主要储存形式,它能与锌结合,限制了锌在人体内的吸收,从而加剧了人体的锌缺乏症状。因此提高小麦籽粒中锌的含量和(或)降低抗营养物质植酸的含量对解决人体锌缺乏现象是非常重要的。本研究通过对目前北方地区部分小麦和小黑麦品种进行品质的分析测定以及一个田间肥料试验来评价小麦籽粒的锌营养品质,并探讨影响小麦籽粒锌营养品质的因素。主要结论如下:(1)通过选取不同小麦主产区的31种面包型小麦(Triticum aestivum L.)和6种小黑麦(×Triticosecale Wittmack),分析其籽粒中部分大量和微量元素、蛋白质以及抗营养因子-植酸的含量。结果表明不同小麦品种间籽粒矿质元素、蛋白质和植酸含量均存在显著差异,微量元素含量顺序为铁>锰>锌>铜;锌、铁、植酸含量的变异较大;大量元素磷和钾以及蛋白质含量较稳定。小黑麦籽粒矿质元素、蛋白质含量与小麦的规律基本相同;籽粒中植酸含量高但同时磷含量也高。不同地区间小麦和小黑麦的主要矿质元素、植酸以及蛋白质含量差异显著,青海的锌铁含量、山东的锰含量以及新疆的铜含量相对较高。所有测试品种中植酸与锌的摩尔比值均高于20。小麦籽粒中植酸与锌、蛋白质之间均呈负相关。综上所述,供试品种中微量元素含量较低且变异大,通过生物强化提高的潜力较大;籽粒中锌铁含量呈显著正相关,因此可以同时提高;植酸蛋白质含量呈负相关,表明选育低植酸品种时有可能同时得到高蛋白含量的品种。(2)在潜在缺锌土壤上,选用5个冬小麦品种进行了土施和喷施锌肥的田间裂区试验。结果表明,供试土壤条件下不同施锌方式对小麦产量均无显著影响,但是,在一定施锌方式下小麦籽粒锌含量大幅度提高。与对照相比,土施、喷施及土施+喷施锌肥提高小麦籽粒锌含量幅度分别为-6.1%、64%和83%,提高小麦籽粒锌携出量幅度分别为-3.6%、69%和83%;同时三个施锌处理降低籽粒中植酸含量的幅度分别为-2.4%、7.2%和1.5%,降低植酸与锌摩尔比的幅度分别为-25%、41%和44%,且不同品种之间也存在一定差异;虽然植酸与锌的摩尔比有所下降,但均高于20,还需进一步降低。此外,单独土施锌肥虽可大幅度提高耕层土壤有效Zn含量,但对籽粒锌含量及生物有效性的影响很小。总之,在小麦生长后期喷施锌肥是提高潜在缺锌土壤上小麦籽粒锌含量和生物有效性的最经济方式,对改善小麦锌营养品质具有重要意义。(3)在田间试验的基础上,对小麦地上部不同部位的锌铁含量进行了分析测定。结果表明,喷施锌肥能显著提高小麦籽粒锌的含量和吸收量,而土施锌肥则受到一定限制;铁的含量和吸收量略微降低,但不显著,因此提倡通过喷施锌肥来提高小麦籽粒锌铁含量和吸收量,从而改善小麦籽粒的锌营养品质;小麦地上部不同器官锌含量一般顺序为籽粒>叶>颖壳>茎,由此表明小麦地上部其他器官的锌含量大部分都转移至籽粒中,有利于锌在籽粒中的累积。更多还原

【Abstract】 Wheat, as the second crop in China, covers daily caloric and mineral nutrition requirement of our northern people. However, wheat mainly distributes in calcareous soil area which is zinc (Zn) deficient or potentially Zn-deficiency, resulting in a lower Zn concentration of wheat grain. Besides, some substances, especially phytic acid, have an inhibitory effect on the utilization (bioavailability) of Zn in the human digestive tract. Phytic acid, as the major anti-nutritional factor, is the storage compound of phosphorus in grain. Phytic acid could bind Zn, resulting in reduce in solubility of Zn in food and finally restricts its utilization in human body. So it is very important to improve Zn concentration and (or) decrease phytic acid concentration. To evaluate wheat Zn nutritional quality, grains of triticale and some variety of wheat grown in northern part were measured. A field experiment was carried out by application of Zn fertilizer to investigate the best method to improve Zn nutritional quality in wheat grain. Conclusions as follows:(1) Variation for microelements, protein and phytic acid in wheat grain existed among different cultivars, in which were large variation among Zn, Fe and phytic acid concentrations, and the concentrations of total P, total K and protein in wheat grain were steady comparatively. Concentrations of the microelements in triticale grain were low, but the concentrations of phytic acid in triticale grain were higher compared with that of wheat grain. Large variations and low concentrations of major mineral elements existed in different regions, and the phytic acid concentrations in Xinjiang and Qinghai provinces were high. The amount of substance of phytic acid to Zn ratios in wheat and triticale grain of all tested cultivars were higher than 20. The correlations among PA and many mineral elements were positive or negative, and the correlation between Zn and Fe concentrations was positive. In Conclusion, there was a low concentration and a large variation for microelements of tested cultivars, and the potential of increasing the concentration of microelements through biofortification was large. The amount of substance of phytic acid to Zn ratios of all tested varieties were higher than 20, resulted in the low bioavailability of Zn, it should be decreased instantly. In view of the significant variation for major mineral elements and phytic acid concentrations of wheat and triticale grain existed in different regions, indicated breeders should consider region factor. The correlation between Zn and Fe concentration was significant, so we can increase Zn and Fe concentrations in wheat grain at the same time.(2) A field experiment with a split plot design was conducted in potentially Zn-deficient calcareous soil, in order to investigate the effect of different Zn application methods (soil application or foliar spray) on increasing grain Zn concentration and Zn bioavailability of 5 winter wheat cultivars. Results showed that, applying Zn fertilizer had little effects on grain yield; however, certain methods of Zn application could increase grain Zn concentration significantly. Compared with the control treatment (no Zn application), the methods of soil application, foliar spray and soil + foliar application of Zn increased grain Zn concentration by -6.1%, 63.9% and 82.6%, and increased grain Zn uptake by -3.6%, 69% and 83%, respectively. The phytic acid concentration was decreased by -2.4%, 7.2% and 1.5%, and the phytic acid to Zn molar ratios were decreased by -25%, 41% and 44%, respectively, under the three treatments of applying Zn. And there were also differences among wheat cultivars. Although the molar ratios of phytic acid to Zn were decreased by Zn application, the ratios were still higher than 20, and it needs a further decrease. The soil application of Zn significantly increased the content of soil DTPA-Zn, however, the effect of soil application of Zn on grain Zn concentration and bioavailability was not significant. In conclusion, comparing with the 3 Zn application methods, the foliar application of Zn fertilizer to wheat at late growth stage (for example: milk and dough stage) is the economical and effective method to attain high Zn concentration and bioavailability in potentially Zn-deficiency calcareous soil, with improving the Zn quality of wheat grain.(3) To investigate the relationship between Zn and Fe concentration in wheat grain, a field experiment was carried out. Results show that foliar application of Zn increased the Zn concentration and content in wheat grain. However, apply Zn fertilizer to soil had no significant effect on wheat grain Zn concentration. Foliar application of Zn was the idea fertilization to improve the Zn nutritional quality of wheat grain. The order of Zn concentration in wheat shoots reduced as grain>leaf>glume>stem, suggesting that most of Zn accumulated in grains.更多还原