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1.
半胱氨酸蛋白酶(cysteine proteinase,CP)是参与植物多种生理过程的一类重要的蛋白酶。为探究CP家族基因在橡胶树(Hevea brasiliensis)中的生理作用,本研究从橡胶树胶乳中克隆了两个CP基因的全长cDNA,分别命名为HbCP2(1 245 bp)(GenBank登录号:KF771829)和HbCP3(1 268 bp)(GenBank登录号:KF771830),分别编码约41和40 kD的蛋白质;获得的基因DNA序列全长分别为1 919和1 634 bp,均包含4个外显子和3个内含子;属于木瓜蛋白酶(C1)家族,分别与同属大戟科植物蓖麻(Ricinus communis)(86.86%)及麻风树(Jatropha curas)(84.74%)的一个CP的亲缘关系最近。实时荧光定量PCR分析显示,HbCP2在雄花而HbCP3在胶乳中的表达量最高;HbCP2和HbCP3的表达受割胶、伤害、乙烯利、赤霉素和茉莉酸调控,但不同基因对同一种处理或同一基因对不同处理的反应程度存在较明显差异。研究结果表明,HbCP2可能参与橡胶树的环境胁迫应答和细胞组织衰老过程的调控,而HbCP3可能参与橡胶树的胶乳再生调控以及病害胁迫应答。本研究为橡胶树CP基因家族的研究,探讨CP在橡胶树中对胁迫应答和胶乳再生调控机制提供了相关信息。 相似文献
2.
本研究采用RT-PCR结合RACE技术,成功地克隆了一个新的巴西橡胶树(Hevea brasiliensis)K+通道蛋白基因并分析了其结构和表达特征.结果表明,该基因cDNA全长1482 bp,拥有1059 bp的开放阅读框(ORE),编码353个氨基酸残基.同源性和聚类分析证实,该基因属于植物KCO家族,命名为HbKCO1(GenBank登录号为EU827609).半定量RT-PCR分析结果显示,HbKCOl在巴西橡胶树不同器官中均有表达,但叶片中表达量最高,茎次之,根、胶乳和树皮中的表达量最低;高钾、盐胁迫(NaC1)和Ca~(2+)可以促进叶片中HbKCOl的表达,钾饥饿和ABA则起到抑制作用;胶乳中HbKCOl的表达几乎不受乙烯利(ET)和茉莉酸(JA)的影响. 相似文献
3.
梨果实石细胞的发育和木质素的合成、转运及沉积密切相关。咖啡酸氧甲基转移酶(COMT)是木质素合成途径中的1种关键酶,主要参与紫丁香基木质素(syringyl lignin,S-木质素)的生物合成。本研究以砀山酥梨果实为材料,利用RT-PCR技术并结合RACE方法,得到砀山酥梨COMT基因的全长c DNA,命名为Pb COMT(Gen Bank登录号为KC905086)。该基因全长1 371 bp,开放阅读框为1 098 bp,编码365个氨基酸。进化树分析发现砀山酥梨COMT蛋白具有很高同源性,与苹果的相似性达到94%。将该基因重组到表达载体p ET-32a(+)中进行原核表达,电泳检测到1条大约60.0 k D的外源蛋白,与预测的融合蛋白分子量相符。荧光定量表达分析得知,梨果实Pb COMT基因表达量变化与木质素的含量变化趋势基本一致,并且和石细胞发育规律有很大的相关性。本研究为阐明梨石细胞发育分子机理奠定基础,为分子调控石细胞含量、改善梨果实口感提供了科学依据。 相似文献
4.
植物特有的NAC转录因子在植物的生长发育、胁迫应答和激素调节等方面具有重要功能。本研究从橡胶树胶乳cDNA中克隆了HbNAC33基因,生物信息学分析显示该基因的完整开放阅读框（ORF）为1 092 bp,编码363个氨基酸。HbNAC33蛋白的N-端第3～156位氨基酸之间含有一个典型的NAC结构域,酵母试验表明,HbNAC33具有转录激活活性,转录激活区在C-端,具备了NAC转录因子的基本特征。序列比对和系统进化分析表明HbNAC33蛋白属于NAC转录因子家族中的ANAC011亚族。实时荧光定量PCR分析表明,HbNAC33在叶中的表达量显著高于其他部位;割胶,乙烯利（ET）和茉莉酸（JA）处理均能诱导HbNAC33的表达上调。以上结果表明,HbNAC33可能参与植物的生长发育和胁迫应答过程。 相似文献
5.
巴西橡胶树HbMCS1基因的克隆及表达分析 总被引：1，自引：0，他引：1
2C-甲基-D-赤藓糖醇-2,4-环化磷酸合成酶（2C-methyl-D-erythritol 2,4-cyclodiphosphate synthase,MCS）是异戊烯基焦磷酸合成途径之一——甲基赤藓糖磷酸（methylerythritol phosphate,MEP）途径中的第五个酶,催化2-磷酸-4- (胞苷-5’-二磷酸)- 2-C-甲基-D-赤藓糖醇生成2-C-甲基-D-赤藓糖醇-2-4-环化磷酸。根据植物MCS的同源序列设计引物,通过RT-PCR结合RACE的方法在橡胶树中获得了与其相应的MCS基因,命名为HbMCS1。序列分析表明HbMCS1长965bp,编码241个氨基酸,该氨基酸序列与长春花、拟南芥、水稻、银杏和三尖杉的MCS同源性分别达到70.8%、69.4%、64.9%和63.3%和62.2%。半定量RT-PCR结果显示,伤害诱导胶乳HbMCS1的表达,乙烯对HbMCS1的表达几乎没有影响;HbMCS1的表达具有组织差异性,在愈伤组织中大量表达,在叶片和胶乳中微量表达。HbMCS1的克隆和表达分析为了解MEP途径在橡胶树胶乳中的作用和对天然橡胶生物合成的调控作用打下了基础。 相似文献
6.
利用生物信息学分析方法挖掘玉米(Zea mays)不同组织间差异表达的基因,揭示玉米生长发育过程的分子机理,本研究从NCBI数据库中下载获得玉米自交系Mo17和B73根和芽的转录组数据,发现了5个在根中高表达的氧甲基转移酶(O-methyltransferase,OMT)基因,在B73全基因组中鉴定到另外的23个拷贝.对玉米的28个氧甲基转移酶基因的结构、保守模体以及进化分析表明,其不同于咖啡酸氧甲基转移酶(caffeic acid O-methyltransferase,COMT)基因和咖啡酰辅酶A氧甲基转移酶(caffeoyl coenzyme A 3-O-methyltransferase,CCoAOMT)基因,是一类新型的氧甲基转移酶基因家族.这类基因家族含有5个进化分支,其中有两个进化分支分别包含苯并噁嗪类基因7(benzoxazinless 7,Bx7)和Bx10,参与苯并噁嗪类物质的生物合成,表明该类基因在玉米的抗病虫反应中发挥着重要作用.染色体结构与进化分析表明,这类新型氧甲基转移酶基因家族的扩增大多是通过串联重复和片段复制来实现的.对这些基因在玉米的巢式关联定位(nested association mapping,NAM)群体亲本中的表达模式分析表明,其表达模式十分复杂.该研究结果为进一步了解COMT基因的生物学功能及其利用提供了理论依据和参考,并对研究该基因家族的催化机制及其表达调控模式具有重要的指导意义. 相似文献
7.
植物阿魏酰转移酶(feruloyl transferase)是负责将阿魏酸从阿魏酰CoA转移至阿拉伯木聚糖分子上的关键酶之一,在阿拉伯木聚糖与木质素的连接上起到关键作用,因此与细胞壁抗降解屏障的形成密切相关。本研究以禾本科模式植物二穗短柄草(Brachypodium distachyon)为材料,通过qRT-PCR技术克隆得到了Bra1(PlantGDB No.:5g14720)基因的cDNA序列,其片段大小为1 369 bp。该基因的ORF编码443个氨基酸,蛋白质的理论分子质量为48.45 kD;基因原核表达以及蛋白质谱分析确定该基因的开放阅读框能正确编码蛋白,分子量大小与理论值基本一致。生物信息学分析显示该Bra1蛋白的氨基酸序列中包含有BAHD酰基转移酶家族特有的HXXXD功能区以及DFGWG保守结构域,说明其是BAHD酰基转移酶家族的一个成员。对二穗短柄草基因组中89个BAHD酰基转移酶氨基酸序列的系统进化树分析发现,这89个酰基转移酶大致划分为4个大的亚族,每个大亚族又包含几个小的亚族,Bra1蛋白(属于第I亚族)与他人研究过的与香豆酸(p-coumalic acid, p-CA)代谢相关的阿魏酰基转移酶(属于第Ⅲ亚族)不属于同一亚族,其蛋白功能可能存在差异;同时,从89个蛋白的编码基因中选取了第Ⅲ亚族另外一个小亚族中的几个基因及与第Ⅲ亚族亲缘关系较远的第Ⅰ亚族的几个基因做了表达分析。qRT-PCR分析表明Bra1基因与其他几个基因相比较,表达量高并且稳定,并且在二穗短柄草成熟期的茎、叶和幼穗等组织器官中的表达量约为其幼苗期的2倍,与二穗短柄草体内阿魏酸的积累特征基本一致,表明这个基因可能参与调控植物细胞壁中的阿魏酸(ferulic acid, FA)介导的交联反应。本研究的结果为该基因的生物学功能研究提供了资料,为禾本科能源植物开发利用和农作物秸秆的再生利用提供了新思路。 相似文献
8.
在成功构建乙烯利刺激条件下巴西橡胶树胶乳差异表达cDNA消减文库的基础上,我们克隆了巴西橡胶树胶乳UEP（ubiquitin extension protein）基因的cDNA全长序列。结构分析表明,该基因cDNA全长771bp,拥有一个468bp的开放阅读框架,77个核苷酸的5`UTR和226个核苷酸的3`UTR,编码156个氨基酸;Southern blot检测结果显示,UEP基因在巴西橡胶树基因组中属低拷贝基因。胶乳UEP基因的表达受到乙稀利的调节。在乙烯利处理后的24小时内,12小时收集的胶乳中UEP基因表达最强,对照和处理6小时的胶乳中表达最弱。乙烯利刺激可以促进巴西橡胶树胶乳增产和加速乳管衰老。这一结果暗示,UEP基因可能参与了乙烯利刺激巴西橡胶树胶乳增产或加速乳管衰老程的分子调控。 相似文献
9.
甾醇14α-去甲基化酶(sterol 14α-demethylase,CYP51)是细胞色素P450家族的重要成员之一。基于从巴西橡胶(Hevea brasiliensis)胶乳转录组文库分离出的目的基因,利用实时荧光定量PCR方法研究橡胶树在不同机械损伤(割次)中和外施乙烯利和茉莉酸后,其胶乳中Hb CYP51 m RNA表达差异,探讨不同刺激方式和水平对Hb CYP51基因表达的影响。BLAST结果表明,本研究克隆了1个与细胞色素P450相关的基因,该基因与毛果杨(Populus trichocarpa)(90%)和苹果(Malus domestica)(88%)中已报道的CYP51同源性最高,命名为Hb CYP51(Gen Bank登录号:KM203677),含有3个外显子和2个内含子,其c DNA全长2 305 bp,包括1 461 bp的开放阅读框(ORF),推测编码1个含486个氨基酸的蛋白。定量RT-PCR分析表明,胶乳Hb CYP51基因是诱导型表达,并被割胶、乙烯利和茉莉酸调控表达,其中受24 h茉莉酸诱导上调表达最显著(P0.01),首次证明了割胶、乙烯利和茉莉酸可激活Hb CYP51的表达。相关性分析表明,割胶刀次与Hb CYP51基因的表达量和胶乳产量均呈极显著正相关(P0.01),而胶乳产量与Hb CYP51基因的表达量无显著相关。研究结果初步说明,Hb CYP51可能是巴西橡胶的重要防御因子,直接或间接参与对割胶和乙烯利的防御反应。 相似文献
10.
JAZ蛋白是茉莉酸(JA)信号调控途径中的重要组分，也是调节JA参与植物生长发育以及逆境应答的关键因子。JAZ9基因是编码TIFY家族JAZs蛋白的基因之一。为研究欧洲葡萄VvJAZ9蛋白参与低温胁迫的功能，本试验以欧洲葡萄霞多丽叶片为研究材料，通过同源克隆获得了VvJAZ9基因序列，其全长807 bp，编码268个氨基酸，定位于第11条染色体，有5个外显子和4个内含子；VvJAZ9蛋白具有JAZs家族蛋白中特有且高度保守的TIFY和CCT＿2结构域，与拟南芥AtJAZ1和AtJAZ2亲缘关系最近。实时荧光定量PCR(qRT-PCR)分析结果表明，VvJAZ9基因在低温处理1～24 h后表达量呈上升趋势，在24 h表达量最高。亚细胞定位结果证实VvJAZ9定位于细胞核。将VvJAZ9的开放阅读框(ORF)序列克隆至原核表达载体pET28b上，在大肠杆菌(E. coli BL21)中经37℃、1.0 mmol·L-1异丙基-β-d-硫代半乳糖苷(IPTG)诱导表达获得VvJAZ9-His融合蛋白，再经抗原免疫，血清纯化后制备anti-VvJAZ9兔源多克隆抗体。蛋白... 相似文献
11.
【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions. 相似文献
15.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
16.
Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization
and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition
with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the
decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots
with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass,
soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration,
N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially
(<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation
in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils,
indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but
the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation
for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community
performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea. 相似文献
17.
《中国生态农业学报》2014,(7)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
18.
《中国生态农业学报》2014,(6)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
19.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献