不同品种杞柳对高锌胁迫的忍耐与积累研究

采用营养液培养实验方法,研究了高浓度Zn对3个杞柳品种"微山湖","大红头"、"一枝笔"生长,耐性及Zn吸收积累的影响.结果表明,Zn对杞柳生长的影响与品种、植物部位以及介质中Zn浓度有关,低Zn(100 μmol·L-1)、高Zn(1 000 μmol·L-1)均不同程度降低了3个杞柳品种的生长参数,低Zn显著减少了"微山湖"、"大红头"的根长及"大红头"根生物量,高Zn显著降低了3个品种株高、根长、生物量等生长参数;3个品种对Zn吸收与积累存在一定差异,地上部Zn含量随介质中Zn浓度升高而降低,根系中Zn含量随Zn浓度升高而增加,Zn在根中含量高于地上部,低Zn时3个品种地上部Zn含量为1477.58～1 583.19 μg·g-1,平均1 530.29 μg·g-1;位移系数(TF)随Zn浓度升高而降低,低Zn时"微山湖"、"一枝笔"位移系数高于"大红头"而接近1;迁移总量随Zn处理浓度增加而降低,3个品种迁移总量为2 332.58～3 871.41 μg,平均3 266.27μg,迁移总量比大于1;耐性指数(TI)随营养液中Zn浓度增加而降低,低Zn时3个品种耐性指数均大于0.5.以上结果表明,高Zn严重干扰了3个杞柳品种的生长,3个品种对低Zn有较强的耐性及积累能力,显示出具有修复≤100 μmol·L-1Zn潜力.     

旱稻苗期品种(系)间锌吸收与利用的差异研究

为了探讨旱稻品种(系)间苗期锌吸收与利用的差异,揭示旱稻前期锌反应和锌高效机理,在温室盆栽条件下,对12个旱稻品种(系)进行不同锌水平处理,出苗后35.d对植株锌含量进行了测定,分析了不同品种(系)间锌吸收和利用率。结果表明,品种(系)间对低锌的敏感性存在显著差异。在低锌条件下适当补施锌肥可显著提高旱稻植株的锌含量和植株体内的锌积累量1～2倍,并增加干物质生产量20%左右,其中云南旱稻、秦爱-3混、辽旱109和91B特9-7四个品种锌的相对生物量均大于100%,对低锌表现不敏感;而旱稻7号则对低锌较敏感,相对生物量仅为68%。     

螯合-缓冲营养液中不同磷锌配比对小麦苗期磷-锌关系的影响

采用螯合-缓冲营养液培养方法对小麦进行了苗期培养试验,在3个磷水平(0、0.6 mmol·L-1、3.0mmol·L-1)和3个锌水平(0、3μmol·L-1、30 μmol·L-1)的完全组合下对小麦苗期的磷-锌关系进行了研究,以期为提高小麦籽粒锌的生物有效性提供理论依据.结果表明,与正常磷锌供应比较,磷锌的缺乏与过量均不利于小麦生长,缺磷比过量供磷的抑制程度更大,而过量供锌比缺锌的影响更为强烈,缺磷和过量供锌主要影响小麦幼苗的分蘖和地上部干物质的积累.过量供磷时,小麦根部存在明显的磷-锌拮抗,抑制了根部对锌的吸收,但磷的供应却提高了锌在小麦植株体内向地上部的转运;缺锌时,小麦叶片会积累大量磷,而供锌后则会抑制磷在小麦植株体内向地上部的转运.在小麦苗期,磷、锌均处于正常水平时其交互作用有利于锌的吸收和向地上部转运,但抑制了磷向叶部的转运.此外,磷、锌的缺乏均降低了叶绿素SPAD值,而磷的正常供应和锌的供应促进了叶绿素的合成.缺磷胁迫时小麦叶片的SOD和POD活性较高,而CAT活性较低;锌缺乏和过量时叶片SOD活性较低,而缺锌时POD和CAT活性较高,供锌后二者活性降低.总之,磷-锌拮抗作用主要发生在小麦根部,但在其他器官内也会发生;且不仅在二者配比不合理时发生,即使在配比合理时也会发生.     

叶面喷施褪黑素调控水稻幼苗耐盐性的浓度效应研究

为了探讨褪黑素(MT)对植物耐盐性的调控,以水稻"盐稻12号"为试验材料,研究了外源MT对75 mmol L-1 Na Cl胁迫下水稻幼苗株高、干重(DW)、根冠比(R/S)、氮磷钾(NPK)及钠(Na)含量的影响,并计算不同处理下各器官的K/Na和K、Na的选择性比率(SK,N a)。结果表明:盐胁迫下,外源喷施25~400μmol L-1 MT能够有效提高水稻植株的株高、DW,降低R/S;且随着MT浓度的升高,该效应越发显著,在MT施用浓度为200μmol L-1时,植株株高和DW均达到最大值。MT浓度为200和400μmol L-1时,植株生长指标差异均不显著。盐胁迫下,喷施MT明显提高植株的NPK含量,降低Na含量,显著增加氮转运系数(N-TF)、磷转运系数(P-TF)和钾转运系数(KTF),显著提高植株根吸收SK,Na(ASK,N a),而叶片运输SK,Na(TSK,Na)随着MT浓度增加逐渐降低。综上所述,盐胁迫下,喷施25~400μmol L-1 MT可明显提高水稻幼苗的NPK吸收,降低植株Na的积累,显著提高了水稻幼苗对K的选择性吸收,维持体内的离子稳态,增加植株地上部和根部生物量积累,从而显著提高水稻的耐盐性,其中,提高水稻耐盐的最适MT浓度为200μmol L-1。     

多种外源性化学物质对烤烟幼苗生长影响及影响差异分析

为研究烤烟根系分泌物对烤烟幼苗生长的影响,在烤烟幼苗生长过程中施加不同浓度与烤烟根系分泌物主要组成成分相同的3种外源性化学物质(苯甲酸、水杨酸和烟碱),模拟烤烟根系分泌物对烤烟幼苗生长的影响,对比三者的影响差异。结果表明,水杨酸、苯甲酸和烟碱3种物质促进烤烟幼苗根系生长和幼苗光合特性的浓度范围主要集中在0~200、0~400、0~800μmol·L-1(其中根表面积达到1 000μmol·L-1,气孔导度和蒸腾速率达到600μmol·L-1),促进烤烟幼苗叶绿素荧光参数的浓度范围主要集中在0~200、0~800、0~800μmol·L-1,而3种外源物质的PSⅡ实际光合效率在200μmol·L-1时均达到最大。由此可知,在烤烟幼苗生长过程中,3种外源性化学物质对幼苗的根系形态结构、光合特性和叶绿素荧光参数表现为低浓度促进、高浓度抑制,且浓度越高抑制程度越大,但不同组分对烤烟幼苗生长影响不同,相同浓度下3种物质的促进作用表现为烟碱苯甲酸水杨酸。本研究可为解决烤烟连作障碍提供理论依据。     

曼地亚红豆杉(Taxus media cv“Hicksii”)栽培基质中适宜的锰、锌、铜浓度及采收时期研究

【目的】紫杉醇具有独特的抗癌机理和广谱强效的抗癌活性,被认证为目前最有效的天然抗癌药物之一。曼地亚红豆杉作为提取紫杉醇重要地天然源料,而备受重视。本试验旨在分析锰(Mn)、锌(Zn)和铜(Cu)三种微量元素对两种树龄曼地亚红豆杉植株生长及紫杉醇含量的影响,为曼地亚红豆杉药用原料林定向培育及通过合理施用微肥确定适宜采收期提供科学借鉴。【方法】以3年和5年生曼地亚红豆杉"Hicksii"幼苗为材料,采用砂基培养方式,使用高效液相色谱检测了施用不同浓度锰(0、4.50、9.00、13.50和18.00μmol/L)、锌(0、0.15、0.30、0.45和0.60μmol/L)和铜(0、0.40、0.80、1.20和1.60μmol/L)对3年和5年生曼地亚红豆杉"Hicksii"树苗生长及紫杉醇含量的影响。【结果】1)3种微量元素对两种不同年龄树苗的生长和枝叶紫杉醇含量影响显著。最适宜3年和5年生树苗生长(株高、地径、新梢长度)和生物量(枝叶与根系鲜/干重)积累的Mn浓度为9.00μmol/L,Zn浓度为0.40μmol/L;3年生树苗的最适宜Cu浓度为0.30μmol/L,5年生为0.15μmol/L。3年生树苗的Mn浓度为9.00μmol/L,5年生树苗为4.50μmol/L以及两种树龄树苗的Zn浓度为0.40μmol/L和Cu浓度为0.30μmol/L时,微量元素有利于两种不同年龄树苗枝叶的紫杉醇积累。高于该适宜浓度则抑制树苗枝叶的紫杉醇积累,且浓度越高抑制作用越强。2)3种微量元素处理下,5年生树苗紫杉醇含量显著高于3年生树苗,对两种树苗紫杉醇含量影响效果顺序为MnZnCu。3)在生长期3~10月,不同浓度Mn、Zn、Cu处理下的两种树苗均表现出相同规律:3~6月树苗紫杉醇积累量逐渐降低,6月降到最低,7月开始逐渐升高,9~10月含量趋于稳定。【结论】施用微量元素Mn 9.00μmol/L、Zn 0.40μmol/L和Cu 0.15~0.30μmol/L,5年龄"Hicksii"树苗,在9~10月份进行采收是紫杉醇含量高的关键点。     

褪黑素浸种对豌豆幼苗生长及镉积累的影响

通过盆栽试验,研究了不同浓度褪黑素浸种对豌豆幼苗生长及镉积累的影响。结果表明:用50、100、150、200μmol/L的褪黑素浸种处理后,豌豆幼苗的生物量、含水量、光合色素含量、抗氧化酶活性均高于对照,且豌豆幼苗植株的镉含量明显降低。当褪黑素浓度为200μmol/L时,豌豆幼苗的生物量、光合色素含量均达到最大值;而根系及地上部分的镉含量最低,分别为6.72 mg/kg和0.104 mg/kg,较对照分别降低了20.28%和46.39%。因此,褪黑素浸种能够促进豌豆幼苗生长,降低其对镉的吸收,其中200μmol/L褪黑素效果最好。     

铝、镉胁迫对空心菜生长及抗氧化特性的影响

为明确铝(Al)、镉(Cd)胁迫对空心菜植株生长、有害元素积累和抗逆生理代谢的影响,采用营养液培养试验,模拟酸性环境(p H值4.5),对空心菜幼苗进行Al、Cd单一及复合处理3周,测定相关指标。试验结果表明,与对照组相比,单独10μmol·L-1Al和0.5μmol·L-1Cd处理促进空心菜植株生长;高浓度Al(100μmol·L-1)、Cd(5μmol·L-1)胁迫导致植株根系和地上部Al、Cd大量积累,诱导叶片中超氧化物歧化酶(SOD)和过氧化物酶(POD)活性增强,丙二醛(MDA)含量增多;叶片叶绿素含量明显降低,植株生物量大幅下降。Al、Cd复合处理植株各器官有害元素含量均显著高于单一毒害处理,尤其是根系,并诱发更严重的植株生长抑制效应和氧化胁迫,表明Al、Cd对空心菜植株的生长抑制和氧化胁迫具有协同性。本试验研究结果可为Al、Cd复合污染酸性菜园蔬菜安全栽培提供理论指导。     

不同基因型玉米品种对Pb的富集特征

为了研究不同基因型玉米品种对Pb的富集特征,选用2个Pb低富集玉米品种(曲辰11号、曲辰3号)和2个Pb高富集玉米品种(靖丰8号、旭玉1446),开展Pb胁迫(2 000 mg·kg-1)下的大田试验,研究了玉米植株生物量的变化、各部位Pb含量、Pb总吸收量、富集与转运规律、土壤p H值及有效态Pb含量。结果表明:(1)与对照相比,Pb胁迫导致4个玉米品种根、茎、叶和籽粒生物量不同程度的下降,总生物量下降9.65%~20.46%,但低富集玉米品种生物量的下降程度小于高富集玉米品种;(2)玉米各部位的Pb含量分配规律为根叶茎籽粒,分别为95.39~121.02、25.56~43.21、14.06~25.41、2.52~5.38 mg·kg-1;低富集玉米品种根的Pb含量高于高富集玉米品种,而茎、叶和籽粒的Pb含量低于高富集玉米品种;玉米植株对Pb的总吸收量为4.46~7.94 mg·株-1,低富集玉米品种植株的Pb总吸收量显著低于高富集玉米品种;(3)不同基因型玉米品种对Pb的富集系数和转运系数均小于1,表现为低富集玉米品种低于高富集玉米品种;(4)不同基因型玉米品种土壤p H值为6.60~6.82,且低富集玉米品种显著高于高富集玉米品种,土壤有效态Pb含量范围为969.86~1 116.15 mg·kg-1。     

9个高羊茅品种种子萌发和幼苗生长对锌胁迫的响应

采用液培试验,研究了不同浓度Zn2+(0、75mg·L-1、150mg·L-1)胁迫对9个高羊茅品种种子发芽势、发芽率、幼苗根长、苗高、鲜重、叶绿素含量、丙二醛含量、细胞质膜透性的影响。结果表明,随Zn2+浓度增加,供试品种中"爱瑞3号"的发芽势和"火凤凰"幼苗的鲜重呈先上升后下降趋势,其他品种两指标均呈下降趋势;"红象"、"金娜多"、"宇宙星"、"火凤凰"、"爱瑞3号"等品种种子的发芽率呈先上升后下降的变化趋势,其他4个品种呈下降趋势;9个品种的幼苗根长、苗高、叶绿素含量均呈下降趋势,丙二醛含量和细胞质膜透性均呈上升趋势。采用Delphi法对8项指标进行综合分析显示,75mg·L-1Zn2+胁迫下,耐锌性顺序为"火凤凰""红象""缤狗"、"家园""宇宙星"、"里园2号""麦哲伦""金娜多""爱瑞3号";150mg·L-1Zn2+胁迫下,耐锌性顺序为"火凤凰"、"里园2号""缤狗""金娜多""爱瑞3号""宇宙星""红象""麦哲伦""家园"。因此,在治理Zn2+污染时,要根据污染程度,合理选用高羊茅品种。     

Mobility of Organic and Inorganic Zinc Fertilizers in Soils

Abstract

Zinc sulfate (ZnSO₄ · H₂O) has traditionally been the “reliable” source of zinc (Zn) fertilizer, but other sources of Zn are also available. Some are derived from industrial by‐products, varying from flue dust reacted with sulfuric acid to organic compounds derived from the paper industry. The degree of Zn mobility in Zn sources derived from these various by‐products is related to the manufacturing process, the source of complexing or chelating agents (organic sources), and the original product used as the Zn source. Many claims are made regarding the relative efficiency of traditional inorganic Zn fertilizers and complexed Zn sources. The objective of this column study was to compare the mobility of several commercial Zn fertilizer materials (organic and inorganic) that are commonly used to correct Zn deficiencies in soils. The sources included three granular inorganic Zn sources, two granular organically complexed Zn sources, and liquid ZnEDTA. Soil columns were leached five times with deionized water. Leaching events were separated by approximately 48 h. At the conclusion of the leaching phase, columns were analyzed for plant‐available Zn. Water solubility was the primary factor affecting Zn movement, not total Zn content or organic complexation of the fertilizers. The Zn sources evaluated can be separated into three groups: ZnEDTA, ZnLigno, and ZnSO₄ were the most mobile Zn sources; the ZnOx55 was less mobile, but seemed mobile enough to meet crop needs; ZnOx26 and ZnSuc were relatively immobile Zn sources.     

Effects of Green Manures and Zinc Fertilizer Sources on DTPA-Extractable Zinc in Soil and Zinc Content in Basmati Rice Plants at Different Growth Stages

Rice is very sensitive to low zinc(Zn) supply in submerged paddy soils and Zn deficiency is one of the major limiting factors in determining rice production in India. A field experiment was conducted during the summer-rainy seasons of 2009 and 2010 at the research farm of the Indian Agricultural Research Institute, New Delhi, to determine the effects of summer green manure crops and Zn fertilizers on diethylenetriaminepentaacetic acid(DTPA)-extractable(available) Zn concentration in soil and total Zn content in Basmati rice cultivar Pusa Basmati 1 at periodic intervals. Summer green manure crops included Sesbania aculeata(Dhaincha),Crotalaria juncea(Sunhemp), and Vigna unguiculata(Cowpea) and the Zn fertilizers used were ethylenediaminetetraacetic acid(EDTA)-chelated Zn, ZnSO_4·7H_2O, ZnSO_4·H_2O, ZnO, and ZnSO_4·7H_2O + ZnO. Beneficial effects of summer green manure crops and Zn fertilizers on DTPA-extractable Zn concentration in soil and total Zn content in dry matter of Basmati rice at periodic intervals were observed, with significant increases in all the determined parameters, in comparison with those in the control(no Zn application or summer fallow). The rate of increase varied among summer green manure crops and Zn fertilizers during both years. Among the summer green manures, incorporation of S. aculeata led to a significant increase in mean Zn content in Basmati rice grain and straw when compared with C. juncea, V. unguiculata, and summer fallow treatments. Among the Zn fertilizers, significant increases in Zn content in Basmati rice dry matter and DTPA-extractable Zn concentration in soil during various growth stages of the plant were recorded with EDTA-chelated Zn application, followed by the application of ZnSO_4·7H_2O, ZnSO_4·H_2O, ZnSO_4·7H_2O + ZnO, ZnO,and no Zn. The highest mean Zn content in Basmati rice grain and straw was recorded with EDTA-chelated Zn application in 2009 and 2010, respectively. The application of ZnSO_4·7H_2O was the second best treatment after EDTA-chelated Zn; however, it was statistically inferior to EDTA-chelated Zn. The lowest values were recorded with the control(no Zn application) during both years of study. The amount of Zn concentration in soil was found to be significantly positively correlated with the Zn content in Basmati rice dry matter during both years. Significantly higher levels of residual fertility in soil after the harvest of Basmati rice were observed with application of EDTA-chelated Zn and incorporation of S. aculeata when compared with those of other Zn sources and summer green manures.     

Zinc Nutrition of Pistachio: Interaction of Zinc with Other Trace Elements

The antagonistic effect of zinc (Zn) with other micronutrients was studied in a calcareous soil under greenhouse conditions. Three levels of Zn were applied to pistachio seedlings along with other essential plant nutrients. It was observed that Zn application had an adverse effect on iron (Fe) concentration in plants. Zinc-deficient plants had significantly greater concentrations of Fe. The results indicated that as the Zn concentration in the substrate was increased, the Fe concentration in plants decreased. Zinc also antagonized the uptake of manganese (Mn) and copper (Cu) in the plants. The roots always showed greater concentrations of these elements than shoots.     

Zinc priming promotes seed germination and seedling vigor of rice

The present study evaluated effects of seed zinc (Zn) priming at concentrations from 0 to 25 mM ZnSO₄ on seedling vigor and viability in rice (Oryza sativa L.). Zinc priming substantially increased Zn concentration in the husk, but not in brown rice. The movement of primed Zn from the husk into the inner layers of rice seed during germination was suggested by Zn concentration declining in the husk coinciding with the increase in brown rice over time (r = –0.62; p < 1%), which did not happen in unprimed seed. Zinc priming significantly enhanced seedling growth and development up to 5 mM. Germination rate, root number, and dry weight were much higher than in unprimed seed, but higher Zn concentrations (10 and 25 mM) depressed seedling vigor. Priming rice seed with 2.5 mM Zn also improved the germination rate of rice in a Zn‐deficient soil, with or without soil Zn application. The results confirm that priming rice seed with Zn can improve germination and seedling vigor and for the first time show how Zn requirement of germinating rice seed and seedlings can be met by the prime Zn accumulated in the husk.     

Soil Zinc Transformations as Affected by Applied Zinc and Organic Materials

Information on soil zinc (Zn) distribution is essential for understanding its chemical reactions and bioavailability. An experiment was conducted to evaluate the effect of wheat straw, cow manure, and vermicompost applied with Zn rates on Zn distribution in a calcareous soil. A sequential extraction scheme was used to fractionate Zn into soluble and exchangeable, bound to carbonate, organically bound, bound to manganese (Mn) oxide, bound to amorphous iron (Fe) oxide, bound to crystalline Fe oxide, and residual forms. In untreated soil, Zn was mainly in the residual fraction. Increasing rates of applied Zn increased all forms of Zn. Carbonate and residual forms showed the greatest increase. Organic materials application increased all fractions, except Mn-oxide form, and this increase was more pronounced for the organically bound form. Concentration of soluble, exchangeable, and organically bound forms was greatest in cow manure–amended samples as compared to other organic materials, suggesting that cow manure contained more bioavailable Zn than other organic materials.     

Zinc Fertilizer Test Kit for Semi-Quantitative Verification of Fertilizer Quality

Zinc (Zn) addition is often recommended for rice culture, but the quality of Zn fertilizer is variable. A semi-quantitative test kit was developed from a zincon colorimetric method to provide buyers an estimate of Zn content in zinc sulfate or zinc oxide fertilizers. The kit includes tools for sample dilution, capsules with sufficient zincon and borax buffer reagent for color development of one sample, and a five-panel color chart to categorize the sample at 0, 5, 10, 15, or 20% Zn. An analysis of user errors indicated that water impurity would cause the most significant problem, resulting in errors of one color category or more. The errors associated with the semi-quantitative measurements of fertilizer and water using tools provided in the kit did not cause significant problems affecting the final color category of the fertilizer, making the kit an acceptable method of estimating Zn content of granular fertilizers.     

Maize Yield Response to Zinc Sources and Effectiveness of Diagnostic Indicators

Maize yield is often limited by zinc (Zn) deficiency. The objectives of this study were to (i) evaluate maize yield response to Zn applied at four different rates, (ii) evaluate the yield response and agronomic efficiency of maize to the application of a complex fertilizer, MicroEssentials SZ (12N–40P–0K–10S–1Zn), compared to different rates of monoammonium phosphate (MAP) + ammonium sulfate (AS) + zinc sulfate (ZnSO4), and (iii) evaluate the association between tissue Zn concentration and soil-test Zn with the maize response to Zn fertilizer. Eleven experiments were carried out during the 2010, 2011, and 2012 growing seasons throughout eight states in the USA. Treatments consisted of four Zn rates of a physical blend of MAP + AS + ZnSO₄ (0, 2.24, 4.48, 6.72, and 11.2 kg/ha Zn) and MicroEssentials SZ at a Zn rate of 2.24 kg/ha Zn. Nitrogen, phosphorus (P), and sulfur (S) rates were balanced across treatments (40 kg/ha P, 22 kg/ha S) and fertilizers were broadcast and incorporated immediately prior to planting. Treatment and location main effects were significant (P < 0.001) on corn yields, whereas the interaction treatment × location was not (P = 0.33). Maize responded positively to Zn fertilization; average yields across locations increased from 10,540 kg ha^?1 without Zn to 11,530 kg ha^?1 with 11.21 kg Zn ha^?1 applied as a physical blend. The yield response and Zn agronomic efficiency of maize with the application of the complex fertilizer at a rate of 2.24 kg Zn ha^?1 averaged 1004 kg ha^?1 and 448 kg maize kg Zn^?1, respectively, significantly higher (P < 0.1) than the yield response and Zn agronomic efficiency with the application of a physical blend with the same Zn rate, which averaged 293 kg ha^?1 and 131 kg maize kg Zn^?1, respectively. The Zn concentration in plant tissue of unfertilized plots varied greatly and was not related to the maize response to Zn fertilizer (r = 0.01; P = 0.98). With respect to soil Zn, a negative but nonsignificant relationship was found between maize response to Zn fertilizer and soil-test Zn (r = ?0.51; P = 0.16).     

Zinc Concentration in Rice (Oryza sativa L.) Grains and Allocation in Plants as Affected by Different Zinc Fertilization Strategies

Concern over the food chain transfer of zinc (Zn) is increasing because of its importance in human health. A field experiment was conducted on a low Zn soil to determine the effect of different Zn fertilization strategies on grain Zn concentration and Zn allocation in different plant tissues of rice. Six treatments were used: (1) no Zn fertilization; (2) soil fertilization at transplanting; (3) Zn soil fertilization at transplanting and flowering; (4) foliar application during grain filling; (5) foliar applications during tillering, flowering, and grain filling; and (6) combination of treatments 3 and 5. Zn fertilization significantly increased Zn concentration in brown rice. The largest effect on grain Zn was observed by combination of soil and foliar applications. The increase in brown rice was much smaller (20%) than the increase in the vegetative parts (100%), indicating that grain Zn concentration of rice is not strongly increased by Zn fertilization. More increased Zn by Zn fertilization was allocated into straw not into grain. From the perspective of human nutrition, it seems that there is too little scope to enhance Zn concentration in rice by fertilization alone. the major bottleneck to increase Zn concentration in rice grain seems to be internal translocation/retranslocation of Zn from shoot to panicle or from rachis to grain, rather than root uptake of Zn from the soil.     

磷锌配施对花生不同生育期磷锌吸收与分配的影响

对植物体内磷–锌复杂的交互关系,采用田间试验,研究了磷锌配施对花生不同生育期磷锌吸收、积累、分配及花生产量的影响。结果表明:施磷和施锌均显著提高了花生地上部干重和产量。相同锌用量下,施磷提高了花生地上部、花生壳和花生仁的磷含量和积累量,但降低了其锌含量、磷锌收获指数和荚果磷利用率。其中,施磷对地上部锌含量的降低程度取决于生育期和锌施用水平。随施磷量的增加,在花生苗期、花针前期及不施锌肥时,花生地上部锌含量显著降低;而在花针后期、结荚期和成熟期及施锌肥时,花生地上部锌含量的降低程度逐渐减弱,表明磷-锌拮抗作用在花生生育前期强于生育后期,不施锌肥强于施锌肥。施磷对花生锌积累量的影响取决于锌供应水平和花生生长部位。不施锌肥时,仅适量供磷促进了地上部锌积累,而施锌肥时,适量供磷和高量供磷均促进了地上部锌积累;不同于地上部,高量供磷显著降低了花生壳和花生仁锌积累量。相同磷用量下,增施锌肥对整个生育期花生各部位磷含量和花生生育后期磷积累量无显著影响,显著增加了花生苗期和花针前期地上部及成熟期花生壳和花生仁的磷积累量、磷收获指数和荚果磷利用率。总之,花生体内磷–锌相互作用大小受其生育期、生长部位和锌供应水平的影响,且施磷对锌的影响较施锌对磷的影响大。     

Phytoextraction of Zinc by Indian Mustard and Tall Fescue

Abstract

This experiment evaluated the capacity of two species, Indian mustard (Brassica juncea Czern.) and tall fescue (Festuca arundinacea Schreb.) to extract zinc (Zn) from soils. Also, this experiment focused on using nitrogen (N) fertilizers to increase the phytoextraction of Zn. Two soils of the Hadley series (Typic Udifluvents) were studied. A treatment array of Zn concentrations in soils was supplied as zinc sulfate. Nitrogen was supplied at 200 mg N/kg of soil as calcium nitrate, urea, or compost. Two successive plantings of Indian mustard in the same media were grown until flowering and harvested. Fescue was grown from seeding to a height of 15 cm, harvested, grown again in the same media to a height of 15 cm, and harvested again. After the second harvests of Indian mustard and fescue, soil samples were taken for analysis of extracts with water and with Morgan's solution. Indian mustard was grown with Zn additions ranging from 0 to 100 mg/kg soil. The shoot mass of Indian mustard in both harvests increased to a soil‐Zn level of 25 mg/kg and then decreased. Although growth decreased as the soil‐Zn levels increased beyond 25 mg/kg, Zn concentration and total accumulation increased linearly as the soil‐Zn levels increased. Zinc concentration and accumulation in Indian mustard were highest in soils amended with urea and were lowest in soils with no fertilizer. Fescue was grown with Zn additions ranging from 0 to 1000 mg/kg soil. The shoot mass of fescue increased to a soil‐Zn level of 125 mg/kg (harvest 1) or 250 mg/kg (harvest 2) and then decreased as the soil‐Zn levels increased. Concentration and accumulation of Zn in fescue increased linearly as the soil‐Zn levels increased. Zinc concentration and accumulation were highest in fescue grown in soils amended with urea and lowest in soils with no fertilizer. The highest accumulation of Zn in fescue (3800 mg/pot) occurred at 1000 mg Zn/kg soil. Highest concentrations of soil Zn were extracted with Morgan's solution or water from soils amended with urea, regardless of the species grown in the soils. Lowest concentrations of Zn were extracted from soils with no fertilizer added, regardless of extract or species. In general, if fertilizers (calcium nitrate, urea, or compost) were added to the soils, the pH decreased. Fescue was easy to grow, tolerated much higher soil‐Zn levels than Indian mustard in this research, and could be a species useful for phytoextraction of Zn.