供磷水平对小麦玉米锌吸收、累积的影响及其作用机制
发布时间：2018-08-12 13:10
【摘要】：全球锌营养缺乏严重影响人体健康。日常饮食中较低的锌摄取量是造成人体缺锌的重要因素之一,尤其是以谷类作为主要食物来源的人群。研究表明,农业生产中大量磷肥的施用显著降低了小麦、玉米籽粒锌浓度。但是田间条件下,磷肥施用如何影响根层土壤有效锌与根系在空间上的匹配、如何影响锌的吸收以及在植株体内的转移和再转移过程,最终影响其在籽粒中的累积等还不清楚。因此,本研究利用田间试验和盆栽试验,研究了磷肥施用水平对高产小麦玉米锌营养的影响,并对其作用机制进行了初步探讨。主要研究结果如下:1.磷肥施用显著影响小麦和玉米产量。在田间条件下,小麦和玉米籽粒产量对磷肥的响应均符合线性-平台的模型:当施磷量分别超过50和12.5 kg P ha-1时,继续施磷不再增加小麦和玉米的产量。同时,达到小麦和玉米叶面积指数和光合速率平台的土壤有效磷(Olsen-P)临界浓度分别为17.7 mg kg-1和12.4 mg kg-1。在小麦上,随着施磷量的增加(0-50 kg ha-1),根系干重、根表面积、根系体积和根长密度显著增加,继续增加施磷量(50 kg ha-1)小麦根系特征参数没有继续增加;在玉米上,相同的拐点出现在25 kg ha-1的供磷水平。2.田间条件下,磷肥施用显著降低了小麦和玉米根系锌浓度以及单位根干重的吸锌量。在小麦上,随着磷肥施用量从0增加至50 kg ha-1,根系锌累积量增加;但当施磷量高于50 kg ha-1,根系锌累积量开始下降。同样,在玉米上,根系锌累积量的最高值出现在25 kg ha-1供磷水平,过低或者过高的磷肥投入均会降低根系锌的累积。3.根系形态特征和根系菌根侵染率是影响根系锌累积的重要因素。在小麦开花期,根系干重随施磷量的增加有利于根系锌的累积;但根系和植株锌累积量以及成熟期籽粒锌累积量随着菌根侵染率的增加(4%-39%)先增加后下降(39%)。玉米盆栽试验的结果进一步表明随着施磷量的增加,菌根侵染率的降低部分解释了根系及总的锌累积量的降低(19%),尤其是在低锌土壤中。从根系与植株锌浓度比值的角度,磷肥用量并没有影响锌由根系向地上部的转移。4.在植株锌累积层面上,磷肥施用降低了小麦植株锌浓度和玉米各器官锌浓度。尽管磷肥施用增加了拔节期小麦植株锌累积量,但开花以后植株锌累积量先随磷肥增加(0-50 kg ha-1)而显著增加,然后显著下降(50kgha-1)。玉米植株锌累积量随施磷量的增加而下降。5.磷肥施用影响小麦玉米花后锌吸收和锌再转移对籽粒锌累积的贡献。在小麦上,籽粒锌的累积主要依靠花后锌从植株向籽粒的再转移(约占47-70%),且随施磷量增加,锌向籽粒的再转移效率呈现下降的趋势;而在玉米上,籽粒锌的累积主要依靠花后的锌吸收(约占67-85%),且花后锌的吸收比例随施磷量增加呈现下降的趋势。6.随着磷肥用量的增加,小麦玉米籽粒锌浓度和锌的生物有效性显著下降。与全麦粉和粗粉的锌生物有效性相比,标准粉、面包粉和精粉的锌生物有效性更高。同时,磷肥施用增加了玉米籽粒的磷/锌、磷/铁、磷/锰和磷/铜的摩尔比值,降低了铁锰铜锌的生物有效性。综上所述,在磷锌拮抗关系中,磷对锌的抑制过程可能主要发生在根系对锌的吸收:较高土壤有效磷导致菌根侵染率显著降低,根系锌吸收显著下降,籽粒锌浓度下降。同时磷肥施用使得籽粒植酸浓度增加,这两方面的综合作用使得籽粒锌的有效性显著下降。
[Abstract]:Global zinc deficiency seriously affects human health. Low zinc intake in daily diet is one of the important factors contributing to zinc deficiency, especially in people whose main food source is cereals. It is not clear how the application of phosphorus fertilizer affects the spatial matching of soil available zinc with root system, the absorption of zinc, the process of transfer and re-transfer in plant, and the accumulation of zinc in grain. The main results were as follows: 1. The yield of wheat and maize was significantly affected by the application of phosphorus fertilizer. Under the field conditions, the response of wheat and maize grain yield to phosphorus fertilizer conformed to the linear-platform model: when the phosphorus application rate exceeded 50 kg and 12.5 kg P HA-1 respectively, the continuous application of phosphorus did not increase small. At the same time, the critical concentrations of soil available phosphorus (Olsen-P) were 17.7 mg kg-1 and 12.4 mg kg-1 respectively. With the increase of phosphorus application rate (0-50 kg ha-1), the dry weight, root surface area, root volume and root length density of wheat and maize increased significantly. The root characteristic parameters of wheat did not continue to increase at 50 kg ha-1; the same inflection point appeared at 25 kg HA-1 phosphorus supply level in maize. 2. under field conditions, the application of phosphorus fertilizer significantly reduced zinc concentration in wheat and maize roots and zinc uptake per unit root dry weight. Zinc accumulation in roots began to decrease when phosphorus application was higher than 50 kg ha-1. Similarly, zinc accumulation in roots of maize appeared at 25 kg HA-1 phosphorus supply level, too low or too high phosphorus application could reduce zinc accumulation in roots. The main factors were as follows: at flowering stage, root dry weight increased with phosphorus application, which was beneficial to the accumulation of zinc in root system; but the accumulation of zinc in root system, plant and grain at maturity increased first and then decreased with the increase of mycorrhizal infection rate (4%-39%). The decrease partly explained the decrease in root and total zinc accumulation (19%), especially in low-zinc soils. From the point of view of the ratio of zinc concentration between root and plant, the amount of phosphate fertilizer did not affect the transfer of zinc from root to shoot. 4. On the level of zinc accumulation in plant, the application of phosphorus fertilizer reduced zinc concentration in wheat plant and zinc concentration in Maize organs. Although the application of phosphorus fertilizer increased the zinc accumulation of wheat at jointing stage, the zinc accumulation increased significantly with the increase of phosphorus fertilizer (0-50 kg ha-1) and then decreased significantly (50 kg ha-1). The zinc accumulation of maize decreased with the increase of phosphorus application. 5. The effect of phosphorus fertilizer application on zinc absorption and zinc redistribution after anthesis of wheat and maize grains. Zinc accumulation in wheat grains was mainly dependent on zinc redistribution from plant to grain (about 47-70%) after anthesis, and the efficiency of zinc redistribution to grain decreased with the increase of phosphorus application. In maize, zinc accumulation in grain mainly relied on zinc absorption after anthesis (about 67-85%) and the proportion of zinc absorption after anthesis decreased with the increase of phosphorus application. With the increase of phosphorus fertilizer application, the zinc concentration and bioavailability of wheat and maize grain decreased significantly. Compared with zinc bioavailability of whole wheat flour and crude flour, zinc bioavailability of standard flour, bread flour and refined flour was higher. At the same time, phosphorus fertilizer application increased phosphorus / zinc, phosphorus / iron, phosphorus / iron, and phosphorus / iron in maize grain. In conclusion, in the antagonistic relationship between P and Zn, the inhibition process of P on Zn may mainly occur in the uptake of Zn by roots. Higher available P in soil led to a significant decrease in mycorrhizal infection rate, zinc uptake by roots, and zinc concentration in grains. As a result, the phytic acid concentration in grains increased, and the zinc availability in grains decreased significantly.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S513;S512.1
本文编号：2179152
[Abstract]:Global zinc deficiency seriously affects human health. Low zinc intake in daily diet is one of the important factors contributing to zinc deficiency, especially in people whose main food source is cereals. It is not clear how the application of phosphorus fertilizer affects the spatial matching of soil available zinc with root system, the absorption of zinc, the process of transfer and re-transfer in plant, and the accumulation of zinc in grain. The main results were as follows: 1. The yield of wheat and maize was significantly affected by the application of phosphorus fertilizer. Under the field conditions, the response of wheat and maize grain yield to phosphorus fertilizer conformed to the linear-platform model: when the phosphorus application rate exceeded 50 kg and 12.5 kg P HA-1 respectively, the continuous application of phosphorus did not increase small. At the same time, the critical concentrations of soil available phosphorus (Olsen-P) were 17.7 mg kg-1 and 12.4 mg kg-1 respectively. With the increase of phosphorus application rate (0-50 kg ha-1), the dry weight, root surface area, root volume and root length density of wheat and maize increased significantly. The root characteristic parameters of wheat did not continue to increase at 50 kg ha-1; the same inflection point appeared at 25 kg HA-1 phosphorus supply level in maize. 2. under field conditions, the application of phosphorus fertilizer significantly reduced zinc concentration in wheat and maize roots and zinc uptake per unit root dry weight. Zinc accumulation in roots began to decrease when phosphorus application was higher than 50 kg ha-1. Similarly, zinc accumulation in roots of maize appeared at 25 kg HA-1 phosphorus supply level, too low or too high phosphorus application could reduce zinc accumulation in roots. The main factors were as follows: at flowering stage, root dry weight increased with phosphorus application, which was beneficial to the accumulation of zinc in root system; but the accumulation of zinc in root system, plant and grain at maturity increased first and then decreased with the increase of mycorrhizal infection rate (4%-39%). The decrease partly explained the decrease in root and total zinc accumulation (19%), especially in low-zinc soils. From the point of view of the ratio of zinc concentration between root and plant, the amount of phosphate fertilizer did not affect the transfer of zinc from root to shoot. 4. On the level of zinc accumulation in plant, the application of phosphorus fertilizer reduced zinc concentration in wheat plant and zinc concentration in Maize organs. Although the application of phosphorus fertilizer increased the zinc accumulation of wheat at jointing stage, the zinc accumulation increased significantly with the increase of phosphorus fertilizer (0-50 kg ha-1) and then decreased significantly (50 kg ha-1). The zinc accumulation of maize decreased with the increase of phosphorus application. 5. The effect of phosphorus fertilizer application on zinc absorption and zinc redistribution after anthesis of wheat and maize grains. Zinc accumulation in wheat grains was mainly dependent on zinc redistribution from plant to grain (about 47-70%) after anthesis, and the efficiency of zinc redistribution to grain decreased with the increase of phosphorus application. In maize, zinc accumulation in grain mainly relied on zinc absorption after anthesis (about 67-85%) and the proportion of zinc absorption after anthesis decreased with the increase of phosphorus application. With the increase of phosphorus fertilizer application, the zinc concentration and bioavailability of wheat and maize grain decreased significantly. Compared with zinc bioavailability of whole wheat flour and crude flour, zinc bioavailability of standard flour, bread flour and refined flour was higher. At the same time, phosphorus fertilizer application increased phosphorus / zinc, phosphorus / iron, phosphorus / iron, and phosphorus / iron in maize grain. In conclusion, in the antagonistic relationship between P and Zn, the inhibition process of P on Zn may mainly occur in the uptake of Zn by roots. Higher available P in soil led to a significant decrease in mycorrhizal infection rate, zinc uptake by roots, and zinc concentration in grains. As a result, the phytic acid concentration in grains increased, and the zinc availability in grains decreased significantly.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S513;S512.1
【引证文献】
相关博士学位论文 前1条
1 曹寒冰;基于降水和产量的黄土高原旱地小麦施肥调控[D];西北农林科技大学;2017年
，本文编号：2179152
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