【摘要】：全球鋅營養(yǎng)缺乏嚴重影響人體健康。日常飲食中較低的鋅攝取量是造成人體缺鋅的重要因素之一,尤其是以谷類作為主要食物來源的人群。研究表明,農業(yè)生產中大量磷肥的施用顯著降低了小麥、玉米籽粒鋅濃度。但是田間條件下,磷肥施用如何影響根層土壤有效鋅與根系在空間上的匹配、如何影響鋅的吸收以及在植株體內的轉移和再轉移過程,最終影響其在籽粒中的累積等還不清楚。因此,本研究利用田間試驗和盆栽試驗,研究了磷肥施用水平對高產小麥玉米鋅營養(yǎng)的影響,并對其作用機制進行了初步探討。主要研究結果如下:1.磷肥施用顯著影響小麥和玉米產量。在田間條件下,小麥和玉米籽粒產量對磷肥的響應均符合線性-平臺的模型:當施磷量分別超過50和12.5 kg P ha-1時,繼續(xù)施磷不再增加小麥和玉米的產量。同時,達到小麥和玉米葉面積指數(shù)和光合速率平臺的土壤有效磷(Olsen-P)臨界濃度分別為17.7 mg kg-1和12.4 mg kg-1。在小麥上,隨著施磷量的增加(0-50 kg ha-1),根系干重、根表面積、根系體積和根長密度顯著增加,繼續(xù)增加施磷量(50 kg ha-1)小麥根系特征參數(shù)沒有繼續(xù)增加;在玉米上,相同的拐點出現(xiàn)在25 kg ha-1的供磷水平。2.田間條件下,磷肥施用顯著降低了小麥和玉米根系鋅濃度以及單位根干重的吸鋅量。在小麥上,隨著磷肥施用量從0增加至50 kg ha-1,根系鋅累積量增加;但當施磷量高于50 kg ha-1,根系鋅累積量開始下降。同樣,在玉米上,根系鋅累積量的最高值出現(xiàn)在25 kg ha-1供磷水平,過低或者過高的磷肥投入均會降低根系鋅的累積。3.根系形態(tài)特征和根系菌根侵染率是影響根系鋅累積的重要因素。在小麥開花期,根系干重隨施磷量的增加有利于根系鋅的累積;但根系和植株鋅累積量以及成熟期籽粒鋅累積量隨著菌根侵染率的增加(4%-39%)先增加后下降(39%)。玉米盆栽試驗的結果進一步表明隨著施磷量的增加,菌根侵染率的降低部分解釋了根系及總的鋅累積量的降低(19%),尤其是在低鋅土壤中。從根系與植株鋅濃度比值的角度,磷肥用量并沒有影響鋅由根系向地上部的轉移。4.在植株鋅累積層面上,磷肥施用降低了小麥植株鋅濃度和玉米各器官鋅濃度。盡管磷肥施用增加了拔節(jié)期小麥植株鋅累積量,但開花以后植株鋅累積量先隨磷肥增加(0-50 kg ha-1)而顯著增加,然后顯著下降(50kgha-1)。玉米植株鋅累積量隨施磷量的增加而下降。5.磷肥施用影響小麥玉米花后鋅吸收和鋅再轉移對籽粒鋅累積的貢獻。在小麥上,籽粒鋅的累積主要依靠花后鋅從植株向籽粒的再轉移(約占47-70%),且隨施磷量增加,鋅向籽粒的再轉移效率呈現(xiàn)下降的趨勢;而在玉米上,籽粒鋅的累積主要依靠花后的鋅吸收(約占67-85%),且花后鋅的吸收比例隨施磷量增加呈現(xiàn)下降的趨勢。6.隨著磷肥用量的增加,小麥玉米籽粒鋅濃度和鋅的生物有效性顯著下降。與全麥粉和粗粉的鋅生物有效性相比,標準粉、面包粉和精粉的鋅生物有效性更高。同時,磷肥施用增加了玉米籽粒的磷/鋅、磷/鐵、磷/錳和磷/銅的摩爾比值,降低了鐵錳銅鋅的生物有效性。綜上所述,在磷鋅拮抗關系中,磷對鋅的抑制過程可能主要發(fā)生在根系對鋅的吸收:較高土壤有效磷導致菌根侵染率顯著降低,根系鋅吸收顯著下降,籽粒鋅濃度下降。同時磷肥施用使得籽粒植酸濃度增加,這兩方面的綜合作用使得籽粒鋅的有效性顯著下降。
[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.
【學位授予單位】：中國農業(yè)大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：S513;S512.1

【引證文獻】

相關博士學位論文 前1條

1 曹寒冰;基于降水和產量的黃土高原旱地小麥施肥調控[D];西北農林科技大學;2017年

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本文編號：2179152