转植酸酶基因(phyA2)玉米定性、定量PCR检测

转植酸酶基因玉米检测是对转植酸酶基因玉米释放进行有效监管的重要前提和技术支撑。本研究根据转植酸酶基因玉米(Zeamays)外源植酸酶基因phyA2序列设计基因特异性引物,进行了定性、定量PCR检测。定性结果显示,该引物可有效检测植酸酶玉米中phyA2基因,而在其他不含植酸酶基因的材料中则检测不到相应基因,表明该引物具有很高的特异性。以玉米内标准基因玉米淀粉合酶异构体zSTSII-2基因(zSSIIb)和植酸酶基因phyA2为对象,进行SYBRGreenⅠ染料法荧光定量PCR反应,绘制2种基因扩增循环数-拷贝数标准曲线图,根据混合样品中(zSSIIb)和植酸酶基因phyA2的拷贝数计算样品中的转基因含量,并做熔解曲线分析。结果表明,zSSIIb和phyA2标准曲线相关系数分别为0.998和0.995,相关性较好,两个基因的熔解曲线均呈单峰型,表明引物特异性较强,混合玉米样品(植酸酶玉米含量分别为1%、0.5%和0.1%)中植酸酶玉米含量分别为1.1%、0.54%和0.17%,实测值与理论值接近。本研究建立了转植酸酶基因玉米定性、定量PCR检测体系,可有效地对转植酸酶基因玉米进行检测。     

磷高效利用型转植酸酶基因玉米

植酸又称肌醇六磷酸,是植物中磷的主要储存形式,也是土壤有机磷的主要存在形式。动植物利用植酸磷,需要利用植酸酶将其降解为肌醇和磷酸。但自然条件下,植物的植酸酶表达量较低,不能提供足量的植酸酶活力。据此,我国科学家培育出磷高效利用型转黑曲霉源植酸酶基因phyA2玉米,该玉米不但可以通过根系向土壤中分泌大量的植酸酶,提高植株对土壤有机磷的利用效率;还可以在玉米的籽粒中积累丰富的植酸酶(干物质植酸酶活力高达7032U·kg~(-1)),提高动物对饲料磷及植酸螯合的钙、镁、锌、铜等微量元素的利用效率。     

转植酸酶玉米大田种植对根际土壤磷含量及组成的影响

转基因作物种植推广中的生态风险是广泛关注的焦点。转植酸酶玉米可以提高动物对玉米籽粒的磷素利用率,但是对土壤磷素的影响尚未见报道。本研究基于2011年开始的田间实验,通过2012年和2013年玉米生长季的动态采样,研究转植酸酶玉米种植对土壤磷含量和组成的影响。结果表明,与亲本相比,转植酸酶玉米对土壤磷的影响强烈依赖于采样时间和磷形态,2012年玉米播种前和2013年抽穗期土壤水溶态磷(H2O-Pi)、氢氧化钠提取态无机磷(NaOH-Pi)和氢氧化钠提取态有机磷(NaOH-Po)含量均显著低于对照;碳酸氢钠提取态有机磷(NaHCO3-Po)在2012年播种前和2013年成熟期显著低于对照,而微生物生物量磷(MBP)只在2013年成熟期有显著差异。种植转植酸酶玉米没有影响土壤全磷(TP)、稀盐酸提取态无机磷(Dil.HCl-Pi)、浓盐酸提取态无机磷(Conc.HCl-Pi)、浓盐酸提取态有机磷(Conc.HCl-Po)和残留态磷(Residual-P)含量。总之,连续3年种植转植酸酶玉米仅在某些采样期对土壤高活性和中等活性磷产生影响。转植酸酶玉米种植对土壤磷素影响的评价和影响机制研究需要结合植物和土壤,并在不同地点开展长期监测。     

组成型表达转植酸酶基因(phyA2)玉米的获得

本研究将黑曲霉（Aspergullus nige）来源的植酸酶基因（phyA2）,通过基因枪法转化玉米（Zea maysL.）幼胚,获得再生苗。RT-PCR和Western blot检测证明,植酸酶基因已经整合到玉米基因组中并在玉米中稳定表达和遗传。转基因植株根组织的酶活性测定及利用植酸作为唯一磷源的培养基生长实验证明,植酸酶基因在植株根组织表达并能够分泌到根围高效利用植酸磷。     

转植酸酶基因玉米提高土壤磷素有效性初步研究

大田栽培条件下,研究了3种转植酸酶(phyA2)基因事件C63、C83-1-7和C84-1-14玉米根系分泌的植酸酶对土壤酸性磷酸酶活性、土壤磷素有效性以及作物磷积累量的影响。结果表明,3种转基因玉米根系植酸酶活性远远高于阴性对照,显著提高了根际土壤酸性磷酸酶的活性、增加了对根际土壤有机磷的活化和利用、减少了土壤速效磷的降低;与阴性对照相比,转phyA2基因玉米生长发育状况更好,C63和C84-1-14植株干重和磷积累量显著高于阴性对照,磷积累量分别是阴性对照的4.3倍和3.4倍。初步说明在土壤条件下,转phyA2基因玉米对土壤有机磷的利用增加,土壤磷素有效性显著提高。     

构建食品级植酸酶黑曲霉工程菌

植酸是植物种子中肌醇和磷的主要存在形式,由于单胃动物体内缺乏能分解植酸的酶,以植酸磷形式存在的磷难以被单胃动物吸收。植酸酶作为饲料添加剂已经广泛应用,但在食品中的应用研究刚刚开始。本研究以黑曲霉(Aspergillus niger)CICC2462基因组DNA为模板,PCR扩增植酸酶基因片段,并在其两端加上糖化酶基因(glaA)的5'同源臂和3'同源臂,构建农杆菌Ti质粒基因置换载体pSZHG-phy。通过农杆菌(Agrobacterium tumefaciens)介导法转化黑曲霉,筛选以植酸酶基因替换糖化酶基因的同源重组转化子,以实现植酸酶基因的高效表达。结果表明,筛选获得4株同源重组转化子,同源重组率为100%,通过分光光度计法测定重组植酸酶菌株的最高发酵酶活为316.2 U/mL,为出发菌株的20.8倍,证明植酸酶phy基因是可以在黑曲霉糖化酶生产菌中实现高效表达。本研究为进一步构建食品级植酸酶工程菌提供了基础资料。     

生态营养学理论在环保型饲料生产的应用

从营养生理角度综述了动物营养及饲料科学最新研究进展,阐明采用理想蛋白氨基酸模式配制日粮可降低N的排泄和节约蛋白质资源;饲料添加植酸酶等酶制剂可减少粪中40％左右P的排泄;微量元素螯合物和微生物制剂的应用可大大提高微量元素利用率,减少甚至杜绝抗生素在饲料中的添加。并提出生产生态环保型饲料的具体措施。     

浅谈饲料微生物添加剂在养殖业中的应用

将饲料微生物添加剂应用于养殖业,具有诸多作用:可以使畜禽消化道内的微生物数量始终保持动态平衡;保证畜禽体内营养均衡;降低有害物质的危害,净化饲养环境;提高动物机体免疫力;提高畜禽的繁殖能力。由此可知,将饲料微生物添加剂应用于养殖业具有重要意义。为充分发挥饲料微生物添加剂在养殖业中的作用,以《饲料微生物添加剂在养殖业中的应用》为课题,从饲料微生物添加剂常用菌种入手,对其进行全面而深入的分析,并在此基础上探究饲料微生物添加剂在养殖业中的应用和应用原则。     

奥瑞金获得农业部转基因植酸酶玉米的商业化批准

奥瑞金种业股份有限公司是一家以农业生物技术研发为基础,以优良品种供给为目的的现代化农业高新技术企业。目前,该公司已收到农业部生物安全证书,并成为世界上第一家获得转基因植酸酶玉米商业化生产的企业。据称,奥瑞金的植酸酶玉米的销售主要面向国内市场。作为首例转基因玉米,植酸酶玉米的面世也带动了下一代玉米种子的生产审批。     

转Bt基因棉叶对土壤微生物多样性的影响

应用Biolog方法研究了转Bt基因棉粉碎叶腐解对土壤微生物群落结构功能多样性的影响。取腐解10d、25d、40d、55d、70d土样分析土壤微生物群落多样性指数及土壤微生物对聚合物、胺类、氨基酸、糖、羧酸和其他类碳源利用情况。结果表明:在腐解过程中,转Bt基因棉粉碎叶土壤微生物群落丰富度下降,群落多样性显著降低,而群落优势集中性明显提高;转Bt基因棉粉碎叶影响了土壤微生物群落对碳源的利用程度,表现为可显著增加对糖类、胺类和氨基酸类碳源的利用,初期显著降低对羧酸类碳源的利用,对聚合物类和其他类碳源的利用率无显著影响;主成分分析表明转Bt基因棉粉碎叶对土壤微生物群落原有结构功能影响具有持续性。     

丛枝菌根真菌对棉花耐盐性的影响研究

盆栽灭菌试验研究丛枝(AM)真菌对棉花耐盐性的影响结果表明,自然盐渍化土壤和人工模拟盐渍条件下接种AM真菌处理的生物产量显著高于不接种处理,相同土壤下菌根真菌对棉花植株生长的促进作用随盐水平的提高而增大,表明AM真菌与植株建立的共生关系有利于棉花在盐渍土壤中生长。盐胁迫下棉花植株对P的需要量增加,接种AM真菌可提高植株含P量,促进植株生长,提高棉花的耐盐性。     

Amounts and distribution of organic phosphorus in some profiles in tanzania

The amounts and distribution of organic phosphorus in profiles from several soil orders commonly occurring in the tropics have been determined. Organic phosphorus was found to decrease with depth, except in a few profiles where the maximum tended to occur in the second horizon. This was attributed to soil erosion due to wind and water, which had carried away most of the original A horizon. Poor vegetative growth and the effect of seasonal burning of the natural grassland were also considered to be contributing factors in the higher amounts of organic phosphorus in the second horizon of some profiles.The distribution of the organic phosphorus in the profiles is considered to be a function of climate, vegetation and the parent material. The C/P ratio differed from order to order and within profiles, suggesting that the humic material could affect the content and nature of the organic P fraction and that it is thus possible that the chemical form of the organic phosphorus is not the same in all of the profiles.     

Some properties of a chrono-toposequence of soils from granite in new Zealand, 2. forms and amounts of phosphorus

The loss of total and organic phosphorus and the transformations of inorganic phosphorus fractions were investigated in a chrono-toposequence of strongly weathered and leached soils formed from granite. Over 80% of the total phosphorus originally present was lost from the system during the period of soil development studied. Non-occluded and occluded phosphorus showed a regular, and residual phosphorus an irregular, overall decline in absolute profile quantity with increasing soil development (i.e. increasing weathering and leaching). The proportion of non-occluded phosphorus in the profile declined asymptotically whereas residual phosphorus increased conversely to non-occluded phosphorus and ranged from 58% to 72% of total inorganic phosphorus in the most strongly developed profiles. Proportions of occluded phosphorus increased with increasing soil development. The relative rates of decline of the inorganic phosphorus fractions and forms were shown to be in the order: acid-extractable CaP > non-occluded P > occluded P > residual P.The final profile in the sequence is considered to represent a terminal steady-state system in which small losses of phosphorus from the system are balanced by gains of phosphorus from the atmosphere.The nature and extent of the vegetation on the sequence profiles was linked with declining acid-extractable CaP and non-occluded phosphorus contents. The tendency towards a heath-type vegetation on the later profiles of the sequence leads to a decline in many properties associated with the organic cycle, including total soil nitrogen, oxidisable carbon, and cation-exchange capacity. Declines in profile weights of several other soil properties were also observed. These included total soil calcium, magnesium, potassium, aluminium, iron, and profile clay content. In many cases the observed declines followed an asymptotic path. The declines were attributed to the completion of weathering of stones and gravels in the later profiles of the sequence whereupon no fresh minerals enter the pedogenetic process.     

Organic phosphorus in upland soil

The nature and behaviour of soil organic phosphorus has been studied in many places of the world, especially in Iowa, U.S.A., and Quebec, Canada.     

纳板河自然保护区土壤酶对不同海拔、坡向的响应

在纳板河自然保护区内分海拔和坡向采集土样,测定分析了尿酶、蛋白酶、蔗糖酶、过氧化氢酶4种主要土壤酶活性和主要养分指标的变化。结果表明:土壤有机质、水解氮含量随海拔升高显著增加;阳坡全氮含量随海拔升高呈现由中间向两端减小的趋势,阴坡全氮含量随海拔升高波动增加;土壤速效磷含量随海拔呈现由中间向两端减小趋势;蛋白酶活性高海拔 > 低海拔,海拔对表层过氧化氢酶活性影响较小,脲酶、蔗糖酶活性随海拔呈现波动。土壤有机质、全氮、水解氮、速效磷含量阳坡 > 阴坡;土壤蛋白酶、过氧化氢酶、蔗糖酶活性阴坡 > 阳坡,各土层土壤脲酶活性阳坡 > 阴坡。各养分含量及酶活性表层 > 中下层。土壤酶活性与各肥力因子间相关关系显著,各土壤酶活性间相关性显著。有机质、全氮、全磷是影响蛋白酶活性的主导因子,速效磷和水解氮为次要因子;全磷、速效磷、水解氮为影响脲酶活性的主要因子,有机质、全磷、速效钾为次要因子。主成分分析结果表明蛋白酶和脲酶活性作为保护区土壤肥力指标具有可行性。     

Chemical Fractions of Phosphorus: The Effect of Soil Orders,Soil Properties,and Land Use

Low availability of phosphorus (P) in Turkish soils is a significant problem of agricultural production depending on carbonates in slightly weathered and iron/aluminum oxides in highly weathered soils. Thus, crop-based P fertilization along with inherited nature of P partition can lead to changes in the amounts and geochemical fractions of phosphorus. For this reason, horizon-based surface samples were taken from 16 soil series that belong to four orders with different pedotransfer functions. The geochemical phosphorus fractions were sequentially extracted by sodium bicarbonate (NaHCO₃), sodium hydroxide (NaOH), citrate-dithionite-bicarbonate buffer system (CBD), hydrochloric acid (HCl), and aqua-regia. Results indicated that weathering sequence was inversely related to plant available P fractions. The fertilizer P was possibly converted to HCl-extractable (Ca-Pi) fraction in calcareous soils through NaOH-Po and NaHCO₃-Po fractions whereas it accumulated in the CBD-P fraction in relatively weathered soils. The carbonates and Al/Fe oxides were most significant constituents in P partitioning as consequences of parent material and weathering chronosequence.     

不同利用方式及施肥对黑土地表磷素养分流失的影响

本文针对黑土利用现状,在吉林农业大学教学试验场黑土区选择不同利用方式的玉米地、休闲地、果园、草地,并在玉米区进行了不同数量的施肥。通过野外试验,采集2002年度5~10月历次自然降雨(共7次)产流及泥沙样品,同时采集降雨前后的耕层土壤样品,研究了黑土区地表径流对磷素养分特征及肥力退化的影响。结果表明:径流TP流失比和DP流失比随覆盖度都表现为先增加后逐渐降低;不同利用方式表层土壤的TP和DP相差很大,就全磷富积表现为果园>草地>玉米地>休闲地,可溶性磷的富积却表现为:休闲地>玉米>果园>草地;随P肥用量的增加而径流磷素(TP、DP)浓度及径流磷素流失量也增加;流失泥沙TP浓度随着磷素施入的增加而增加;泥沙磷素浓度、泥沙磷素流失量均比CK大,但泥沙流失量均比CK小;增施氮磷虽能增加作物的产量,但N、P施用量必须适度,从试验期间径流、泥沙的TP、DP流失量观测,可以初步得出黑土氮磷配合施肥的宜于选配的方案是B5区N98P44N570。     

Forms of phosphorus in soils of Rajasthan

Phosphorus in soils is found to be present in organic combinations, inorganic form or in adsorted form on clay complex. Different forms of soil phosphorus have different solubilities and consequent availability in soils. A knowledge about the content and types of soil phosphorus enables one to understand the organic behaviour and predict the response of added phosphatic material to crops (Parker 1953). The form in which phosphorus is present in soil is directly related to pH and CaCO₃ in the soil as well as the intensity of the development of the soil. Williams (1950) has found that in calcareous soils of South Australja most of the phosphorus was in combination with calcium, whereas in acid soils it forms compounds with alumina and iron. Hibbard (1931) concluded that in alkaline and calcareous soils, phosphorus exists mostly in the form of hydroxyapatite, chloroapatite, and the like. Kanwar and Grewal (1959) studied fractionation of phosphorus in Punjab soils and reported that differences in the nature and amounts of the phosphorus present in acid and alkaline soils of the State explain the causes of different phosphatic fertilizer responses to the crops. A similar report has been given by Goel and Agarwal (1959) who studied the fractionation of phosphorus in Kanpur soils and concluded that the mature soils are rich in iron and aluminium bound phosphorus and respond better to phosphatic fertilizer than the immature soils rich in Ca²⁺ and Mg²⁺ bound phosphorus. Chai Moo Cnoo and Caldwell (1959) reported that Fe³⁺ and Al³⁺ bound phosphorus was abundant in acid soils while Ca²⁺ and Mg²⁺ bound phosphorus content in alkaline soils, and organic phosphorus agreed, in general, with the content of organic matter, with some deviations.     

长顺冗雷河小流域草地治理模式下土壤肥力评价

采用野外调查和室内分析相结合的方法,对贵州省长顺县冗雷河小流域坡耕地、人工草地和天然草地3种地类的全氮和碱解氮,全磷和有效磷,全钾和有效钾,酸碱度,有机质进行了研究,以层次分析法进行肥力综合评价,揭示冗雷河小流域草地治理模式下对土壤肥力的影响。结果表明:坡耕地实施人工种草措施后,土壤全氮含量相对增加42.64%,碱解氮增加50.86%,中层和下层（20—30 cm）土壤碱解氮改善最为明显;土壤全磷含量相对增加45.24%,有效磷降低23.58%,坡耕地相比草地在全磷含量上相对较为匮乏,但用于作物吸收的有效磷素却高于人工草地;土壤全钾和有效钾含量降低,pH值无变化,其中全钾含量相对降低43.28%,有效钾降低37.32%;土壤有机质含量相对增加77.24%,其中表层（0—10 cm）、中层和下层土壤有机质含量分别提升48.06%,85.58%和107.78%,中层和下层土壤有机质含量改善幅度大。天然草地综合肥力指数最大,坡耕地最小,天然草地综合肥力指数是人工草地的1.09倍,是坡耕地的1.14倍,人工草地是坡耕地的1.05倍。土壤肥力整体水平上得到提升。     

Evaluation of Groundnut Genotypes for Tolerance to Phosphorus Deficiency

Phosphorous (P) is one of the most deficient nutrients owing to its fixation and low mobility in acid soils. A total of 324 genotypes were screened in both P sufficient and insufficient conditions to evaluate the P uptake efficiency. Thirty-four responsive genotypes were evaluated in solution culture with two checks, ICGV 86590 and JL 24. The components of variability revealed high magnitude and highly heritable nature of the variation. Highly responsive genotypes to P insufficiency; ICG 14475, ICGV 92188, and M 68 were further tested for phosphorus uptake efficiency at 15, 30, and 45 days after sowing (DAS) along with checks in sand culture in pots. ICG 14475, ICGV 92188, and ICGV 86590 were found superior in both acquisition and utilization of phosphorus due to enhanced root production for P exploration and shoot expansion, respectively. JL 24 was poor in acquisition due to lack of response in root traits under P insufficiency.