国内外主要粮食作物对施用锌肥响应的研究进展

【目的】锌 (Zn) 对于人体健康至关重要,缺Zn会影响人体正常发育,并易受致病菌的入侵,降低人体耐受氧化胁迫的能力。人体主要通过摄食的方式补Zn,占全球50%的用于种植粮食作物的耕地缺Zn,主要粮食作物中可食部分的Zn含量普遍偏低,世界上50%的人口健康受到了影响。本文通过探讨国内外主要粮食作物对Zn肥施用的响应,旨在为以后相关的作物富Zn研究提供理论依据。主要进展施用Zn肥可以有效改善主要粮食作物籽粒部分的缺Zn状况,土施与叶面喷施均可提高主要粮食作物小麦、水稻和玉米可食部分的Zn含量,并能够增加产量。但由于受到土壤pH、有机质含量等的影响,土施Zn肥有效性偏低,施用的量较大,Zn肥的表观利用率低于叶喷Zn肥,叶喷Zn肥的增产效果显著低于土施Zn肥;锌肥的效果还受营养元素之间交互作用的影响,Zn与P和Fe存在拮抗作用,与Cu存在协同作用;Zn元素在籽粒的不同组份中为不均匀分配,在麦麸、小麦籽粒、白面粉中的含量依次递减,在水稻籽粒、糙米、精米中的含量也依次下降,Zn元素在主要食用的白面和精米中的分配较低;小麦籽粒部分的Zn来自于根的吸收以及茎和叶的再分配,水稻籽粒部分的Zn主要来自于根的吸收。问题与展望目前有关Zn在肥–土–作物系统中的迁移分配规律尚不清楚,施用Zn肥的成本较高,肥料中各营养元素的最佳投入量与最佳配比还不确定。因此,Zn肥施用可在以下六个方面进行深入研究:1) Zn元素在肥–土–作物系统中的吸收分配机制,清楚掌握Zn元素在肥–土–作物系统中的富集与分配规律,建立全国主要农田土壤的Zn数据库,构建产量、富Zn量与Zn肥之间的响应模型;2) 研发肥料施用技术及新型廉价肥料,降低补施Zn肥的成本;3) 继续研究Zn与其它营养元素之间的协同和拮抗作用,找到最佳投入量与最佳配比,整体提升粮食作物的营养价值;4) 改善土壤理化性质,提高Zn肥对于农作物的有效性及其肥效的持久性;5) 加强高富Zn品种的筛选,获得对Zn肥高产量与高富Zn量响应的品种类型;6) 研究主要粮食作物富Zn的分子生物学机制,进行品种的改良。

Research advances on the response of main food crops to zinc fertilization at China and abroad

【Objectives】Trace element Zn is essential for human health. Without sufficient Zn nutrition, the development of human body might be affected, be more vulnerable to the invasion of pathogenic bacteria and susceptible to diseases, and less tolerate to oxidative stress. Zn supplement of human body is mainly from food intake, however, about 50% of the world’s arable land is deficient in Zn, and the Zn contents in edible parts of main food crops are generally low. In this paper, we discussed the response of main grain crops to Zn fertilizers for providing a theoretical basis for future research on Zn enrichment.Major advancesDeficiency of Zn in grain parts of main food crops could be improved by soil application and forliar spraying of Zn fertilizers, and both the two ways showed significant effects in improving the Zn contents in edible parts of main food crops (wheat, rice and maize) and the yields, the effectiveness of soil application of Zn fertilizers is low and the applied rate is high, due to the influence of soil physicochemical properties, such as soil pH, organic matter content, the apparent utilization rates of soil application of Zn fertilizers are lower than those of leaf spray, the leaf spray of Zn fertilizers could not increase yields as high as soil application did; interactions between the nutrient elements affect the application effect of Zn, Zn is antagonistic to P and Fe, synergistic to Cu; Zn is not evenly distributed in the different grain components, the contents of Zn gradually become lower in bran, grain and flour of wheat, the same in rice grain, brown rice and polished rice, and Zn contents in the main consumables flour and rice are low; Zn in grain part derives from both the root absorption and the redistribution of stems and leaves in wheat, and mainly from root absorption in rice.Suggestions and expectationsAt present, the migration and distribution of Zn in the fertilizer-soil-crop systerm is not clear, the cost of the application of Zn fertilizer is high, the optimal input and the ration of the different nutrient elements is still uncertain. In view of problems existing in the application of Zn fertilizers and its causes, this future researches should focus on the following six aspects: 1) Study the uptake and distribution of Zn in the fertilizer-soil-crop system, clearify the enrichment and allocation of Zn in the fertilizer-soil-crop system, and establish a database of Zn in major farmland soils throughout the country and build a response model between yield and Zn content and Zn fertilizer; 2) Research of effective Zn feitilization technology and cost effective Zn fertilizers; 3) Study the synergistic and antagonistic effects of Zn with other nutrient elements, so as to find satisfactory input way and achieve the best nutritional value of food crops as a whole; 4) Improve soil physicochemical properties, so to alleviate the effectiveness and durability of Zn fertilizers; 5) Screening grain crop cultivars with both high yield and high Zn content; 6) Study the Zn-rich molecular biological mechanism of the main food crops, serving breeding of crop cultivars.