Microbial Phytases and Phytate: Exploring Opportunities for Sustainable Phosphorus Management in Agriculture

Myo-inositol phosphates (phytates) are important biological molecules produced largely by plants to store phosphorus. Phytate is very abundant in many different soils making up a large portion of all soil phosphorus. This review assesses current phytase science from the perspective of its substrate, phytate, by examining the intricate relationship between the phytate-hydrolyzing enzymes and phytate as their substrate. Specifically, we examine available data on phytate’s structural features, distribution in nature and functional roles. The role of phytases and their localization in soil and plant tissues are evaluated. We provide a summary of the current biotechnological advances in using industrial or recombinant phytases to improve plant growth and animal nutrition. The prospects of future discovery of novel phytases with improved biochemical properties and bioengineering of existing enzymes are also discussed. Two alternative but complementary directions to increase phosphorus bioavailability through the more efficient utilization of soil phytate are currently being developed. These approaches take advantage of microbial phytases secreted into rhizosphere either by phytase-producing microbes (biofertilizers) or by genetically engineered plants. More research on phytate metabolism in soils and plants is needed to promote environmentally friendly, more productive and sustainable agriculture.

Combining Phytate/Ca^(2+) Fractionation with Trichloroacetic Acid/Acetone Precipitation Improved Separation of Low-Abundant Proteins of Wheat (Triticum aestivum L.) Leaf for Proteomic Analysis

Proteomic assessment of low-abundance leaf proteins is hindered by the large quantity of ribulose-1,5-bisphosphate carboxylase/oxygenase （Rubisco） present within plant leaf tissues. In the present study, total proteins were extracted from wheat （Triticum aestivum L.） leaves by a conventional trichloroacetic acid （TCA）/acetone method and a protocol first developed in this work. Phytate/Ca2＋ fractionation and TCA/acetone precipitation were combined to design an improved TCA/acetone method. The extracted proteins were analysed by two-dimensional gel electrophoresis （2-DE）. The resulting 2-DE images were compared to reveal major differences. The results showed that large quantities of Rubisco were deleted from wheat leaf proteins prepared by the improved method. As many as （758±4） protein spots were detected from 2-DE images of protein extracts obtained by the improved method, 130 more than those detected by the TCA/acetone method. Further analysis indicated that more protein spots could be detected at regions of pI 4.00-4.99 and 6.50-7.00 in the improved method-based 2-DE images. Our findings indicated that the improved method is an efficient protein preparation protocol for separating low-abundance proteins in wheat leaf tissues by 2-DE analysis. The proposed protocol is simple, fast, inexpensive and also applicable to protein preparations of other plants.

Association of Phytate Formation with Grain Filling in Rice

The grain-filling characteristics of six rice varieties (combinations) and the relationships between their relative biochemistry composition during phytate synthesizing and grain plumpness were studied. Regarding results for ISHR1, ISHR2, R198 and JW21, with good grain plumpness, the two-step-filling in superior spikelets and inferior spikelets was not clear, while for ISHR3 and 559, with poor grain plumpness, it was very clear. From booting stage to flowering stage, the contents of phytate and inositol in varieties with good grain plumpness was obviously higher than those in varieties with poor grain plumpness. While at grain filling stage, the content of inorganic phosphorus in varieties with poor grain plumpness was obviously higher than that in varieties with good grain plumpness. The contents of phytate and inositol from booting stage to flowering stage was highly significantly correlated with the initial filling power (R_0), the mean filling rate (R_M) and grain filling percentage (P_(GF)), and the content of inorganic phosphorus at grain filling stage was negatively significantly correlated with R_0, F_M and P_(GF). Furthermore, effective approach to improving grain filling was put forward.

A major quantitative trait locus controlling phosphorus utilization efficiency under different phytate-P conditions at vegetative stage in barley

Organic phosphorus（P） is an important component of the soil P pool, and it has been proven to be a potential source of P for plants. The phosphorus utilization efficiency（PUE） and PUE related traits（tiller number（TN）, shoot dry weight（DW）, and root dry weight） under different phytate-P conditions（low phytate-P, 0.05 mmol L^-1 and normal phytate-P, 0.5 mmol L^-1） were investigated using a population consisting of 128 recombinant inbred lines（RILs） at the vegetative stage in barley. The population was derived from a cross between a P-inefficient genotype（Baudin） and a P-efficient genotype（CN4027, a Hordeum spontaneum accession）. A major locus（designated Qpue.sau-3 H） conferring PUE was detected in shoots and roots from the RIL population. The quantitative trait locus（QTL） was mapped on chromosome 3 H and the allele from CN4027 confers high PUE. This locus explained up to 30.3 and 28.4% of the phenotypic variance in shoots under low and normal phytate-P conditions, respectively. It also explains 28.3 and 30.7% of the phenotypic variation in root under the low and normal phytate-P conditions, respectively. Results from this study also showed that TN was not correlated with PUE, and a QTL controlling TN was detected on chromosome 5 H. However, dry weight（DW） was significantly and positively correlated with PUE, and a QTL controlling DW was detected near the Qpue.sau-3 H locus. Based on a covariance analysis, existing data indicated that, although DW may affect PUE, different genes at this locus are likely involved in controlling these two traits.

Effect of phytate on the amylosynthetase activity and rice grain quality

Phytate of three concentrations was sprayed on the leaves of an indica rice Yuanfengzao in heading stage, full heading stage, filling stage and wax ripeness stage respectively. The effects of phytate on the enzyme activity in endosperm and rice grain quality were determinated. Plants sprayed with distilled water were used as control. It was showed that spraying solutions in full heading stage had the most manifest effect. The activity of amylosynthetase between the 100mg/kg and 150mg/kg phytate treatment was identical, which was 7.4% higher than that of 50mg/kg treatment. On the other hand, amylase activity on the 50mg/kg treatment was 12.5% and 8.7% lower than those

Preventive effect of regional radiotherapy with phosphorus-32 glass microspheres in hepatocellular carcinoma recurrence after hepatectomy

AIM: To evaluate the preventive effects of phosph-orus-32 glass microspheres (P32-GMS) in the recurrence of massive hepatocellular carcinomas (HCCs) after tumor resection. METHODS: Twenty-nine patients with massive HCCs received local P32-GMS implantation after liver tumors were removed,while the other 38 patients with massive HCCs were not treated with P32-GMS after hepatectomies. The radioactivity of the blood,urine and liver were examined. The complications,HCC recurrence and overall survival rates in the patients were analyzed. RESULTS: P32-GMS implanted in the liver did not cause systemic absorption of P32. There were no significant differences of postoperative complications between the patients with and without P32-GMS treatment. The short-term (six months and 1 year) and long-term (2,3 and over 3 years) recurrence rates in patients who received P32-GMS radiotherapy were signifi cantly decreased,and the overall survival rates in this group were signifi cantly improved. CONCLUSION: P32-GMS implantation in the liver can significantly decrease the postoperative recurrence and improve the overall survival in HCCs patients after hepatectomy. This therapy may provide an innovative method in prevention of HCC recurrence after operation.

前期饲粮非植酸磷水平对仔鹅屠宰性能、肉品质及器官指数的影响

试验旨在研究前期(1~35日龄)饲粮非植酸磷水平对仔鹅屠宰性能、肉品质及器官指数的影响。选取1日龄健康江南白鹅公雏300只,随机分成5组,每组6个重复,每个重复10只仔鹅。试验分为两个时期,饲养前期(1~35日龄)饲粮为含非植酸磷水平分别为0.18%、0.28%、0.38%(对照组)、0.48%和0.58%的玉米-豆粕型饲粮,后期(36~63日龄)试验鹅统一饲喂正常非植酸磷水平(0.37%)的玉米-豆粕型饲粮。结果显示:28日龄时,0.28%组和0.38%组仔鹅对饲粮中磷的表观利用率显著高于0.18%组、0.48%组和0.58%组(P<0.05)。饲粮非植酸磷水平为0.18%~0.58%时,63日龄鹅屠体重和全净膛重随饲粮非植酸磷水平的增加呈线性增加(P<0.01),且0.48%组和0.58%组极显著高于0.18%组、0.28%组和对照组(P<0.01);0.58%组空肠重量极显著高于对照组和其他处理组(P<0.01),且随饲粮非植酸磷水平的增加呈线性增加(P<0.01);0.48%组和0.58%组腿肌剪切力极显著大于对照组和0.28%组(P<0.01);前期饲粮非植酸磷水平有影响63日龄仔鹅心脏指数的趋势(0.05≤P<0.10)。前期饲粮非植酸磷水平与腿肌剪切力及28日龄磷的表观利用率呈二次曲线关系(P<0.05),由此预测剪切力值最低和磷表观利用率最高的非植酸磷含量分别为0.29%和0.35%。综上所述,在钙水平为0.80%的情况下,若后期饲喂正常水平非植酸磷(0.37%)饲粮,仔鹅前期饲粮非植酸磷水平在0.28%~0.38%可节约磷用量并获得较好的磷利用率和腿肌肌肉嫩度;将水平提高到0.48%~0.58%可改善屠宰性能,但降低了腿肌嫩度和磷表观利用率。

磷-锡环保复合协效阻燃剂制备及其在PVC中的应用

通过沉淀包覆法制备不同包覆比例的植酸锡包覆羟基锡酸锌(tin phytate coated zinc hydroxystannate,ZHS@Sn-Phyt)复合协效阻燃剂,并应用在软质聚氯乙烯(polyvinyl chloride,PVC)中.采用X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和热重分析(thermo-gravimetric analysis,TGA)对包覆结构进行分析表征,同时对PVC复合材料进行极限氧指数(limiting oxygen indexand,LOI)、锥形量热(cone calorimetry,CONE)和力学性能测试.结果表明:在羟基锡酸锌(zinc hydroxystannate,ZHS)表面和植酸锡(tin phytate,Sn-Phyt)包覆层之间以Sn—O—P—O—Zn离子键的形式形成稳定的包覆结构;当复合阻燃剂中Sn-Phyt∶ZHS质量比为1∶9时,对PVC的阻燃效果最佳,表现出较好的协同阻燃作用,LOI比加入相同份数ZHS的PVC样品增加了1.6%,热释放速率峰值和热释放总量分别降低了18.9%和31.7%,残炭率提高了6.1%,烟释放总量相差不大,拉伸强度和断裂伸长率分别为26.79 MPa和296.5%,也均优于后者.因此,制备了一种高效绿色阻燃剂用以阻燃PVC,所制备的磷-锡协效阻燃剂具有绿色环保和工艺简单的优点.

Effect of Soybean Cultivars on the Nutrients and Consumer Acceptance of Soymilk

Soymilk is one of the most available beverages, an alternative to dairy milk and is recognized for its nutritional value. The nutritional quality, the presence of anti-nutritional factors, isoflavones and sensory acceptability of soymilk depended on the soybean variety as well as the processing conditions. The soymilks from conventional and specialty Brazilian soybean cultivars were compared regarding the composition and consumer acceptance. There were significant differences on the protein, oil, sugars, isoflavones, presence of anti-nutritional factors (phytate and trypsin inhibitor activity) and NSI (nitrogen solubility index) among cultivars and soymilks and for sensory acceptance of soymilks. The preference mapping and cluster analysis identified three different segments of consumers. The soymilk from the conventional cultivar BRS284 achieved higher and similar acceptance score for the three consumer’s segments while the lipoxygenase free cultivars (BRS213 and BRS257) and specialty cultivar BRS216 showed higher score for two segments of consumers. The sensory evaluation of soymilk from different soybean cultivars could improve consumer uptake.

Amino acid and mineral digestibility,bone ash,and plasma inositol is increased by including microbial phytase in diets for growing pigs

Background The effect of microbial phytase on amino acid and energy digestibility is not consistent in pigs,which may be related to the phytase dosage or the adaptation length to the diet.Therefore,an experiment was conducted to test the hypotheses that increasing dietary phytase after an 18-day adaptation period:1)increases nutrient and energy digestibility;2)increases plasma P,plasma inositol,and bone ash of young pigs;and 3)demonstrates that maximum phytate degradation requires more phytase than maximum P digestibility.Results Data indicated that increasing inclusion of phytase[0,250,500,1,000,2,000,and 4,000 phytase units(FTU)/kg feed]in corn-soybean meal-based diets increased apparent ileal digestibility(AID)of Trp(quadratic;P<0.05),and of Lys and Thr(linear;P<0.05),and tended to increase AID of Met(linear;P<0.10).Increasing dietary phytase also increased AID and apparent total tract digestibility(ATTD)of Ca and P(quadratic;P<0.05)and increased ATTD of K and Na(linear;P<0.05),but phytase did not influence the ATTD of Mg or gross energy.Concentrations of plasma P and bone ash increased(quadratic;P<0.05),and plasma inositol also increased(linear;P<0.05)with increasing inclusion of phytase.Reduced concentrations of inositol phosphate(IP)6 and IP5(quadratic;P<0.05),reduced IP4 and IP3(linear;P<0.05),but increased inositol concentrations(linear;P<0.05)were observed in ileal digesta as dietary phytase increased.The ATTD of P was maximized if at least 1,200 FTU/kg were used,whereas more than 4,000 FTU/kg were needed to maximize inositol release.Conclusions Increasing dietary levels of phytase after an 18-day adaptation period increased phytate and IP ester degradation and inositol release in the small intestine.Consequently,increasing dietary phytase resulted in improved digestibility of Ca,P,K,Na,and the first 4 limiting amino acids,and in increased concentrations of bone ash and plasma P and inositol.In a corn-soybean meal diet,maximum inositol release requires approximately 3,200 FTU/kg more phytase than that required for maximum P digestibility.

有机酸活化植酸-矿物络合物的作用机制与影响因素综述

植酸(myo-inositol hexakisphosphate,肌醇六磷酸)是一种有机磷类化合物,是土壤磷库的重要组成部分,占土壤有机磷的50%~80%,总磷的20%~50%。然而,植酸分子含有6个磷酸基团,具有强络合能力,极易被土壤矿物(针铁矿、赤铁矿、勃姆石等)吸附形成难溶性或不溶性络合物,导致生物可利用性极低。植酸-矿物络合物的形成及稳定性决定了植酸被活化和利用的难易程度,该过程受植酸浓度、pH值、环境温度、络合方式、参与配位的磷酸基团数、吸附亲和力及土壤矿物种类等因素的影响。植物根系和微生物分泌的有机酸(柠檬酸、草酸等),可通过竞争吸附、络合、溶解等方式活化络合物中的植酸,并释放与植酸络合的矿质元素,提高土壤中磷和矿质元素的生物可利用性,对减少外源磷肥施用和降低磷流失污染风险具有重要的现实意义。因此,本文通过综述土壤中植酸-矿物络合物的形成过程与影响因素(植酸浓度、环境介质pH值、环境温度)、稳定性及其影响因素(络合方式、矿物类型),重点阐述有机酸活化植酸-矿物络合物的机制(配体交换、竞争吸附、氢键作用、溶解作用等)、效率及影响因素(络合物种类、稳定性及植酸吸附密度,有机酸种类与浓度,环境pH值),以期为提高土壤内源植酸磷的生物有效性和利用率提供理论依据和技术参考。

AZ31B镁合金表面无机-有机复合化学转化与膜层性能

[目的]镁合金具有优异的加工性能、抗震性能、电磁屏蔽性能等,但较差的耐蚀性限制了镁合金的使用寿命,因此对其进行有效的表面防护处理具有重要的意义。[方法]通过化学转化法在AZ31B镁合金表面原位制备了无机-有机复合膜层。先通过正交试验得到较优的转化液配方,进而研究了转化处理时间对膜层形貌和耐蚀性的影响,并通过X射线光电子能谱(XPS)分析了较佳条件下所得膜层的成分。[结果]化学转化的较优配方和工艺参数为:植酸钠3 g/L,六氟锆酸3 g/L,处理时间40 s,温度25℃。所得转化膜主要由MgO、MgF_(2)、ZrO及有机氟化物组成,具有均匀的色泽、适中的厚度和致密的结构,展现出良好的耐蚀性。[结论]该无机-有机复合转化工艺可有效提高镁合金基体的耐蚀性。

植酸锌对固废基复合涂料阻燃性能的影响

以工业固废硅灰为基料,以植酸锌(ZnPA)作为生物基阻燃剂,以三聚氰胺(MEL)作为增效剂,构建阻燃体系,采用溶胶-凝胶法制备硅灰基复合防火涂料。通过锥形量热仪(CONE)、扫描电镜(SEM)、同步热分析仪和热解动力学等手段,研究了ZnPA用量对硅灰基复合防火涂料阻燃性的影响。结果表明,与未加ZnPA相比,加入2.5%ZnPA的硅灰基复合涂层的热释放速率峰值和产烟量分别降低了41.83%和42.84%,在731~940℃时的活化能Eα增大了22.73%,复合防火涂层在燃烧过程中形成了不可燃的互穿网络结构,提高了残余层的强度,有效提高了涂料的阻燃性能。

不同标记时间的锝[^(99)Tc^(m)]植酸盐注射液在靶器官中放射性摄取量的显著性差异分析

目的判断在标记后第0小时和标记后第6小时锝[^(99)Tc^(m)]植酸盐注射液在小鼠肝脏和甲状腺中的放射性摄取率是否存在显著差异,为产品有效期的制定提供依据。方法以3批锝[^(99)Tc^(m)]植酸盐注射液和9只小鼠为实验对象,将小鼠分为3组,每组3只。通过尾静脉注射的方式向第1~3组小鼠体内注射第1~3批标记后第0小时的锝[^(99)Tc^(m)]植酸盐注射液604~734kBq,通过单因素方差分析(One-Way ANOVA)对实验数据进行统计分析,先行判断批间显著性差异;以3批锝[^(99)Tc^(m)]植酸盐注射液和18只小鼠为实验对象,将小鼠分为6组,每组3只。其中,通过尾静脉注射的方式向第1~3组小鼠体内注射第1~3批标记后第0小时的锝[^(99)Tc^(m)]植酸盐注射液440~584kBq,同法向第4~6组小鼠体内注射第1~3批标记后第6小时的锝[^(99)Tc^(m)]植酸盐注射液440~584kBq,通过单因素方差分析对实验数据进行统计分析。结果第1~3组小鼠肝脏和甲状腺摄取率的假设检验F值分别为0.307和0.800,均小于F-crit值5.143,即3批锝[^(99)Tc^(m)]植酸盐注射液的肝与甲状腺放射性摄取率差异没有统计学意义;第1~3组、4~6组小鼠肝脏和甲状腺摄取率的假设检验F值分别为0.084和0.941,均小于F-cirt值4.494,即标记后0h和标记后6h的锝[^(99)Tc^(m)]植酸盐注射液在小鼠体内的分布差异无统计学意义。结论标记6h后的锝[^(99)Tc^(m)]植酸盐注射液在小鼠肝脏和甲状腺的放射性摄取率均满足药典要求,且药物仍然可以保持良好的生物分布特性,锝[^(99)Tc^(m)]植酸盐注射液的有效期制定为不大于6h。

肉桂精油-β-环糊精微胶囊的制备

肉桂精油有很好的抑菌性能,而其挥发性使得其作为食品防腐剂的应用受到了限制。为扩大肉桂精油在食品中的应用,采用β-环糊精包埋法研究了肉桂精油微胶囊工艺,通过单因素试验和正交试验确定肉桂精油微胶囊制备的较好工艺条件为芯壁材质量比(肉桂精油∶β-环糊精)为1∶8,包合温度为70℃,包合时间为2 h。此工艺条件下制备的微胶囊包埋率可达86.75%。

施磷量对双季早、晚稻产量及稻米品质的影响

以双季早、晚稻超高产品种陆两优996和淦鑫688为材料,以金优402和汕优10号为对照,研究了施磷量对其产量和稻米品质的影响。结果表明,施磷对早稻的增产效应大于晚稻,陆两优996和淦鑫688的适宜施磷(P2O5)量为30 kg/hm2,而对照品种的适宜施磷量为60 kg/hm2。施磷对早稻的增产作用主要是增加有效穗数,而对晚稻的增产作用主要是增加每穗粒数。施磷降低稻米蛋白质含量,对整精米率和垩白的影响在品种间和季别间存在差异。施磷显著增加稻壳和糙米中的植酸含量,其中,晚稻糙米植酸含量的增加程度大于早稻,但糙米中植酸含量在不同施磷量处理间差异不显著。

植酸酶生产菌的筛选及生长条件的研究

从单胃动物的粪便垃圾堆中分离出一种可分泌植酸酶的青霉 .进一步的研究表明这种青霉培养液最佳的淀粉含量为 40g·L-1.青霉生长与其分泌植酸酶之间存在矛盾 .青霉生长旺盛时产酶少 ,测出的酶活性低 .青霉生长缓慢时产酶多 ,测出的酶活性高 .

影响高粱饲用价值主要内在因素及其对策

大量研究结果显示,饲用高粱含有3种物质不利于高粱在动物体内的消化,一是酚类化合物,二是醇溶蛋白,三是植酸。本文从3类化合物的特征、对消化酶的抑制作用、醇溶蛋白与淀粉以及氨基酸的消化率、植酸和植酸磷以及酶制剂在高粱型畜禽饲粮中的应用等方面,就高粱在动物饲料应用的研究动态和进展进行了简要综述。

微生物植酸酶或麦麸对断奶到肥育阶段猪的生产性能和骨骼发育的影响

本研究选用４８头（长白×梅山）×（汉普夏×梅山）断奶仔猪（１１．０±０．２４ｋｇ），在断奶到肥育阶段（１１～５０ｋｇ为前期，５０～９０ｋｇ为后期），研究不同来源植酸酶对植酸磷利用的影响。设４个试验处理，每试验处理设４个重复（每重复３头猪）。在玉米─豆饼基础饲粮中，分别添加微生物（Ａｓｐｅｒｇｉｌｌｕｓｎｉｇｅｒ）来源的植酸酶（ＭＰ，前期１２００ＰＵ／ｇ，后期１０００ＰＵ／ｇ），麦麸（Ｗ８，前期１０％，后期２０％）、及无机磷（前期０．３％，后期０．２％），组成４种不同的试验饲粮。试验结果表明，ＭＰ或ＷＢ使猪的生产性能达到了与添加无机磷类似的水平（Ｐ＞０．０５），明显高于对照组（Ｐ＜０．０１）．并且明显提高５０及９０ｋｇ时 骨和掌骨的强度（Ｐ＜０．０１）。试验猪５０ｋｇ时，ＷＢ对骨骼强度的作用低于ＭＰ或无机Ｐ（Ｐ＜０．０１），但９０ｋｇ时三个处理组之间没有差异（Ｐ＞０．０５）。以上结果说明在断奶到肥育阶段，ＭＰ可以代替添加无机磷的作用，ＷＢ对生产性能的改善作用与ＭＰ和无机磷相似。ＷＢ的有益作用是由于其中含有较多的植酸酶。

施锌方法对小麦籽粒不同脱皮组分中锌与植酸及蛋白质分布的影响

【目的】探讨施Zn方式对小麦籽粒不同脱皮层次中Zn、植酸及蛋白质含量的影响,为通过农艺措施提高小麦全粒尤其是可食部分（胚乳）Zn含量及其生物有效性提供理论依据。【方法】以陕715（Zn高效基因型）和西农889（Zn低效基因型）为供试材料,设置不施锌肥（对照）、土施锌肥（15 kg/hm2）、喷施锌肥（质量浓度为3 g/L,总量为1.5 kg/hm2）、土施＋喷施锌肥4个处理,采用裂区设计进行田间试验,并利用JNMJ3型碾米机对小麦籽粒进行脱皮分层（从外向内依次为P1、P2、P3、P4、P5、P6,其中P1~P5主要为麸皮部分,P6主要为胚乳部分）,分析了小麦籽粒各层中Zn、植酸和蛋白质含量。【结果】在2个喷施Zn肥（土施＋喷施、喷施）处理下,P1-P5和P6层的Zn含量均显著增加,P1-P5中Zn平均分别增加53.4%,43.2%,P6层中分别增加61.1%,52.7%,而单纯土施Zn肥效果不明显。Zn、植酸在小麦籽粒P2层含量最高,蛋白质则在P3层含量最高,3种组分含量随着脱皮进程的增加从外层到内层呈现递减趋势;3种施Zn方式对P1-P5植酸含量影响不显著,但增加了P6层植酸含量;同时降低了籽粒各层蛋白质含量。土施＋喷施和喷施Zn肥处理均能显著降低P1~P5和P6层中植酸与Zn的物质的量（[植酸]/[Zn2＋]）,土施Zn肥处理则不能。【结论】Zn、植酸和蛋白质在小麦籽粒中分布不均匀,在籽粒外层含量均很高,尤其是糊粉层,胚乳中最少,且这种分布规律基本不受施Zn方式和小麦品种的影响。喷施Zn肥是提高潜在性缺Zn土壤上小麦全粒Zn尤其是胚乳部分Zn含量和生物有效性较为经济的方式,对缓减人体Zn缺乏有重要意义。