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1.
在YMA平板上对18株分离自四川的慢生型花生根瘤菌进行Fe、Co、Zn、B、Mo、pH的耐性实验。结果表明,在柠檬酸铁、钼酸铵浓度为0.50%时供试菌株均能生长,当柠檬酸铁浓度增至1%时有22%的供试菌株能正常生长,当钼酸铵浓度增至0.6%时有11%的菌株能正常生长;在硼酸浓度为0.05%时所有菌株生长受抑制或不生长;在硫酸锌或硫酸钴浓度为0.025%时分别有50%或28%的菌株能正常生长,当浓度增至0.075%时,供试菌株不生长或61%的菌株不生长。表明供试菌株对Fe、Mo的耐性较强,而对Co、Zn、B的耐性较弱;不同根瘤菌株对同一微量元素的耐性差异较大,同一根瘤菌对不同微量元素的耐性差异也较大。多数菌株在pH 6.0~8.0范围内生长正常,耐碱能力比耐酸能力强。因此,在研制"根瘤菌 微量元素"复配的根瘤菌剂时,微量元素不能随意复配,同时还需注意菌剂的pH。 相似文献
2.
尖孢镰刀菌(Fusarium oxysporum)是兼性寄生真菌,引起农作物枯萎病,防治困难。研究来自不同寄主的尖孢镰刀菌在不同pH马铃薯蔗糖(PS)琼脂培养基上的生长情况,构建动力学模型,以了解培养基的初始pH差异对尖孢镰刀菌生长特性的影响。测定了尖孢镰刀菌菌株在不同pH培养基、25℃培养条件下的生长速度,构建生长动力学模型。供试6个尖孢镰刀菌菌株在pH为3~10的液体培养基中均有不同程度生长,不同菌株对培养基pH的影响规律相似,在不同pH的PS液体培养基中培养14 d后,液体培养基的pH均有靠近6~7的趋势。在pH为3~9的培养条件下,尖孢镰刀菌菌落可以分成4类:菌丝型、粘滑层型、菌丝粘滑层型和菌丝带粉状物,各菌株的菌丝和培养基色泽也有所差异。同一菌株在培养基不同pH下生长速度不同,其生长的最适pH为6~8,菌落平均直径最大(45~49 mm),亚适pH为4、5和9;而在pH为3、10和11时菌落直径明显变小(17~21 mm)。培养14 d后培养基pH对菌落形态、色泽有一定的影响,不同菌株在不同pH培养基培养下产孢量也存在差异。pH在4~8时其平均产孢量最大,达(223.8~273.3)×104cfu.mL 1,其中pH为6.38(自然pH)时产孢量最高,pH为11时产孢量最低。供试菌株在不同pH条件下的菌落生长速度和产孢量变化动力学模型均符合二次曲线方程。 相似文献
3.
从生长在西北部分矿区的豆科植物根瘤中分离筛选到对重金属有抗性的38株根瘤菌,采用PCR-RFLP分子技术进行16S rDNA指纹图谱分析,选取每种类型的代表菌株进行16S rDNA全序列测定,建立系统发育树状图,并对38株菌进行Zn、Hg、Cu、Cd和Pb5种重金属的抗性研究。结果表明,供试菌株分别归属于中华根瘤菌属(Sinorhizobium)、根瘤菌属(Rhizobium)和土壤杆菌属(Agrobacterium)。代表菌株CCNWSX1277和CCNWSX1294可耐受2.0mmol·L-1的Zn2+,CCNWSX1277可耐受0.25mmol·L-1的Hg2+,多数代表菌株可耐受1.6mmol·L-1的Cu2+,仅3株代表菌株可以耐受Cd2+,其中CCNWSX1277能耐受1.4mmol·L-1的Cd2+,所有代表菌株能耐受2.5mmol·L-1的Pb2+。Agrobacterium属的2株代表菌株对5种重金属均有较强的耐受性;而Rhizobium属的4株菌和Sinorhizobium属的3株菌对5种重金属的耐受性不同,表现出较大的差异。总体来看,供试菌株对重金属的耐受性顺序为Agrobacterium〉Rhizobium〉Sinorhizobium。 相似文献
4.
土壤和大豆品种是影响根瘤菌遗传多样性的主要因素。本研究通过土壤捕捉试验,分别从冬小麦茬口和玉米茬口土壤中种植的4个大豆品种根瘤中分离得到149株快生根瘤菌和49株慢生根瘤菌。对这些菌株进行16S rDNA限制性酶切分析(ARDRA)、16S-23S基因间隔(IGS)以及共生基因(nod C)的限制性片段长度多态性分析(RFLP),考察土壤茬口和大豆品种对大豆根瘤菌遗传多样性的影响。ARDRA分析结果表明,快生根瘤菌全部属于中华根瘤菌属(Sinorhizobium),慢生根瘤菌全部属于慢生根瘤菌属(Bradyrhizobium)。IGS酶切分型将所有菌株分为3种图谱类型,其中型Ⅰ与辽宁慢生根瘤菌(B.liaoningense)的模式菌株酶切图谱类型完全一致,型Ⅱ和型Ⅲ与费氏中华根瘤菌(S.fredii)的模式菌株酶切图谱类型完全一致。综合以上结果,本研究分离到的菌株分属于以上2个种。在两种茬口土壤中快生根瘤菌费氏中华根瘤菌均为优势种群,在冬小麦茬口土壤中的比例(平均95.18%)远高于玉米茬口土壤(平均53.78%)。‘冀豆12’大豆品种的费氏中华根瘤菌在两种茬口土壤中所占比重均高于其他品种。对菌株的IGS基因型与宿主大豆品种的相关性分析表明,大豆品种与根瘤菌IGS基因型之间具有一定相关性。nod C-RFLP酶切分型结果表明,土壤茬口和大豆品种对菌株的共生基因无明显影响。本研究表明根瘤菌、土壤茬口和大豆品种间存在一定的相关性。土壤茬口对根瘤菌的种群结构影响较大,大豆品种对根瘤菌的基因型具有一定的选择性。 相似文献
5.
试验比较了不同保存温度和培养基Ca3(PO4)2含量下解磷根瘤菌SL01的生长和解磷能力。结果表明:固体培养条件下,增大Ca3(PO4)2添加量能促进菌落生长,8g·L-1处理菌落直径(d)为5g·L-1、3g·L-1、1g·L-1和0.5g·L-1处理的116.9%、127.7%、130.1%和132.7%。0~8g·L-1的Ca3(PO4)2含量范围内,菌株的解磷能力无显著差异,故更适于以溶磷圈直径D与菌落直径d的比值D/d来衡量菌株在固态环境如土壤中的解磷能力;其菌液最适宜于15℃下保存,4℃次之。不同保存温度下菌种的解磷能力为-18℃-10℃4℃15℃28℃35℃;不同保存温度下SL01菌株的菌落直径为4℃15℃-18℃28℃-10℃35℃;菌液在不同温度下保存60d后的活菌含量为15℃4℃28℃-10℃35℃-18℃。 相似文献
6.
对分离自陕西、甘肃金属尾矿废弃地寄主为刺槐、鸡眼草、草木樨等23种豆科植物的188株根瘤菌进行了7种重金属的抗性分析、最大抗性水平(MRL)的确定和抗性菌株的系统发育研究。结果表明,菌株之间对重金属的耐受性存在较大差异,大部分菌株表现出对Hg^2+、Cd^2+、Cr^6+(〈0.5 mmol·L^-1)敏感,而对Pb^2+(〈2.5 mmol·L^-1)不敏感。在液体培养基中,CCNWSX0403和CCNWSX0360可耐受4.0 mmol·L^-1 Zn^2+,分别可耐受2.4 mmol·L^-1 和2.8 mmol·L^-1 Cu^2+,CCNWGS0139可耐受0.4 mmol·L^-1 Hg^2+,CCNWSX0003可耐受2.4 mmol·L^-1 Ni^2+,CCNWGS0284和CCNWGS0142可耐受4.8 mmol·L^-1 Pb^2+。9株抗性菌株的16S rDNA全序列分析表明:CCNWGS0122和CCNWSX0003分别属于中慢生根瘤菌属(Mesorhizobium)和中华根瘤菌属(Sinorhizobium);4株对Pb^2+、Hg^2+耐受性较强的菌株CCNWSX0386、CCNWGS0139、CCNWGS0284和CCNWGS0142均属于土壤杆菌属(Agrobacterium);而属于慢生根瘤菌属(Bradyrhizobium)的3株菌CCNWGS0309、CCNWSX0403和CCNWSX0360对Cu^2+、Zn^2+耐受性较好。总体上Agrobacterium对Hg^2+和Pb^2+的耐受性较好,Bradyrhizobium比Rhizobium、Sinorhizobium、Mesorhizo 相似文献
7.
从长期经有机磷农药污染的土壤中分离到一株能高效降解三唑磷的菌株mp 4,通过生理生化实验和16 S rDNA同源性序列分析将该菌鉴定为苍白杆菌属(Ochrobactrum sp.)。mp 4菌能以三唑磷为唯一碳源生长,对三唑磷的降解率为98. 3%。在25~37℃、pH值为6.6时生长较好,27~32℃、pH7 5~8 8时有较好的降解性能。在水稻大田试验中,米壳的三唑磷残留去除率为91 9%,糙米的三唑磷残留去除率为100%。 相似文献
8.
GUS基因标记法对慢生花生根瘤菌竞争结瘤和接种效果的研究 总被引:1,自引:0,他引:1
应用GUS基因标记技术,可简便、快速、准确、原位、直观地确定标记花生根瘤菌株形成的根瘤,从而方便地研究标记菌株与土著根瘤菌的竞争结瘤能力。无氮水培试验表明,标记菌株gusA4-5、gusA2-9分别与土著菌混和接种占瘤率为71.4%、77.0%。盆栽试验表明,接种供试菌株Spr4-5、Spr2-9占瘤率分别为57.9%、63.0%,比对照极显著增产52.5%、22.7%;接种Spr4-5比Spr2-9极显著增产24.2%。初步说明两个供试菌株的竞争结瘤力比土著根瘤菌强,菌株Spr2-9强于Spr4-5;Spr4-5比Spr2-9有效性高,是结瘤适量,竞争结瘤能力强的高效菌株。 相似文献
9.
通过构建快生型大豆根瘤菌B52的基因文库和三亲本杂交,将增效因子DNA片段导入优良的慢生型大豆根瘤菌22-10中,获得携带来自快生菌增效因子DNA片段的工程菌株HN32,经盆栽和小区试验,证明基因工程菌株HN32比出发菌株22-10平均增产6%,比对照平均增产13.2%~16.9%,相当于每公顷施75~150kg尿素.1992~1995年,在广西推广应用基因工程大豆根瘤菌HN322.16万hm2,每公顷平均增产19%,投入产出比1:30。增加经济效益1409.8万元。 相似文献
10.
通过含有R68.45质粒的大肠杆菌将快生型大豆根瘤ACCC15067菌株的大质粒转到慢生型大豆根瘤菌61A76菌株中去,共接合转移出22个接合子菌株,对其中的12个菌株进行了与83-119大豆的共生接种试验,其效果是部分接合子菌株超过供体菌和受体菌对接合子BF2-A1菌株进行了质粒检测。田间应用亦有增产趋势。 相似文献
11.
山西省快生型大豆根瘤菌资源调查和鉴定 总被引:3,自引:0,他引:3
从山西省主要大豆产区的不同土壤和大豆品种中分离得到的38个快生型大豆根瘸菌株的鉴定表明,这些分离物的IAR除了氨苄青霉素外,均较慢生型为低。38个菌株被分为4个血清型,其中2个为新发现的,命名为2077和2120型。细胞成分N%含量为2.01-3.78,C%含量为50.52-55.53%,N/C值<10。所检测的7个菌株都有1-2个大质粒,且每个均有112 Md的大质粒。分离株的共生效应和结瘤竞争由于大豆品种不同而有显著差异。本研究表明,我国大豆起源地之一的山西省,快生型大豆根瘸菌的分布广泛,分离频率较高,菌株类型也多。 相似文献
12.
In Ethiopia, inoculation of soybean with rhizobial inoculants is not common practice, but could provide an option to increase grain yields in low nitrogen (N) acidic soils. In these acid soils, the selection of acid tolerant rhizobia is one strategy that may increase the performance of soybean. In this study, rhizobial strains isolated from Ethiopian soils were evaluated for their acid tolerance and symbiotic N fixation efficiency with soybean, in controlled environments. Following this, four isolated rhizobial strains were evaluated in six field experiments in major soybean growing areas of Ethiopia. Inoculation with the commercial strain or with one of two locally sourced isolates, that were developed as inoculants, improved soybean yield. The yield increase due to inoculation with the commercial strain was consistent and greater than other treatments, while the increase due to the two locally sourced strains was comparable to, or greater than, application of 46 kg N/ha in soils, where the resident rhizobial population was ≤1.4 × 103 cfu/g soil. For soils with high background rhizobial populations, there was no response to inoculation. In one of the experimental sites (Bako), the percentage of N fixed (%Ndfa) was 55 for the commercial strain and 35 for the local strain, ES3. This study demonstrated that field validation is a necessary step in the selection of acid-tolerant strains of rhizobia to increase soybean production for Ethiopia. 相似文献
13.
Promiscuous soybean lines have been bred on the basis that they would nodulate freely without artificial inoculation. However, our recent studies have demonstrated that the indigenous rhizobia are not able to meet their full nitrogen (N) requirement. Rhizobia inoculation might be necessary. We examined the competition for nodule formation among native Rhizobia spp. and two inoculated Bradyrhizobia strains (R25B indigenous strain and a mixture of R25B+IRj 2180A indigenous strain from soybean lines in the savanna of northern Nigeria), their effect on N fixation, and their contribution to the yield of four soybean cultivars, grown in the field in three different agroecological zones in the moist savanna of Nigeria. About 34% of nodules were formed by the mixture of introduced R25B+IRj 2180A, while R25B formed only about 24% of the nodules but did not influence biomass and grain yield production. The indigenous rhizobia strains that nodulated the soybean varieties fixed up to 70% of their accumulated total N, confirming the promiscuous nature of these soybean varieties. Even though these varieties fixed about 75 kg N ha -1; this was not enough to sustain their optimum grain yield, as earlier reported. However, the grain yield from inoculated soybean was not significantly higher than that from the uninoculated soybean, showing a degree of competitiveness among the introduced rhizobial strains and the native rhizobia population. 相似文献
14.
研究铅锌尾矿区豆科植物根瘤菌对铅锌的响应,可为利用豆科植物改良尾矿区土壤及植被恢复提供理论依据。会泽铅锌尾矿土壤被铅锌严重污染,铅锌含量分别是全国土壤(A层)的110倍和54倍。通过现场采样、室内分离和耐性培养,对10株分离自会泽铅锌尾矿区豆科植物的根瘤菌的铅、锌单盐与铅锌双盐逆境进行了耐性研究。结果表明,该区域的豆科植物根瘤菌对铅、锌单盐逆境具有良好的耐性,但是对铅锌双盐的耐受明显减弱。对这10株根瘤菌的生理生化特征研究结果表明,会泽尾矿区根瘤菌的生理生化特性存在广泛差异,根瘤菌铅锌耐性越强,其阳性生理生化特征越多。一株与三叶草共生接瘤的HS3,一株与香豌豆共生接瘤的HX6和一株与猪屎豆共生接瘤的HZ8,它们不但表现出耐铅锌,而且生理代谢广泛,显示这3株根瘤菌在铅锌尾矿区的利用具有较好的潜能。 相似文献
15.
Summary Six fast-growing soybean rhizobia (Rhizobium fredii) and thirteen slow-growing soybean rhizobia (Bradyrhizobium japonicum) were examined for resistance to 10 antibiotics. Axenic studies were carried out to determine the competitiveness of dual-strain inocula consisting of fast- and slow-growing rhizobia isolated from subtropical-tropical soils for nodule occupancy on a hybrid of Asian and US soybean cultivars. Nodule occupancy was determined by intrinsic resistance to erythromycin and neomycin. The results showed wide variability in resistance to 10 antibiotics for fast- and slow-growing rhizobia. The intrinsic antibiotic resistance of fast- and slow-growing rhizobia was extremely high against nalidixic acid (400 g ml–1) and penicillin (200 g ml–1). The competitive ability of inoculant strains for nodule occupancy varied for different combination sets and with the plant growing media. Our results show that fast-growing rhizobia nodulate a hybrid of Asian and US soybean cultivars. Fast-growing soybean rhizobia did not completely exclude nodulation by the slow-growing strains, which formed 0–79% nodules, depending on the strain used in the inoculum. 相似文献
16.
Soil samples were collected at an altitude of 500, 1,060, 1,500, 1,950, 2,400 and 3,100 m, respectively, from Shennongjia, a forest reserve in Hubei province (central China). Their corresponding pHs were 5.50, 4.91, 5.64, 5.28, 5.49 and 4.60. By using a plant trap method, a total of 25 soybean rhizobia were isolated from the soil above an altitude of 1,500 m and all identified to be Sinorhizobium fredii. Their genetic biodiversity was characterized by 16S–23S rDNA internally transcribed spacer (ITS) region polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and random amplification DNA (RAPD) analysis. All the tested strains produced a 2.1 kb 16S–23S rDNA ITS fragment. After digestion with three restriction endonucleases (HaeIII, MspI and CfoI), respectively, great variations in 16S–23S rDNA ITS PCR-RFLP patterns were observed. The tested strains could be differentiated into 11 ITS genotypes. The genotypes of rhizobia were not related to geographical location. Twelve primers were applied to RAPD analysis and a dendrogram was obtained, showing that all the strains (including reference strain S. fredii USDA205) were divided into two diverging groups. Moreover, each group could be further divided into two subgroups. Both RAPD and 16S–23S rDNA ITS PCR-RFLP analysis indicated that a high degree of genetic diversity existed among S. fredii strains isolated from Shennongjia virgin soils. Since Shennongjia is an unexploited forest region in central China and the gene centre of soybean is located in China, the symbiotic genes harboured by these strains may be of great importance and the rich diversity of these strains might contribute to the adaptation of soybean to an alpine environment. 相似文献
17.
Chinnaswamy Appunu Narayanasamy Sasirekha Vaiyapuri Ramalingam Prabavathy Sudha Nair 《Biology and Fertility of Soils》2009,46(1):57-63
The diversity among 269 rhizobia isolated from naturally occurring root nodules of soybean collected from two different agro-ecological
regions of India, based on RFLP and sequences of the intergenic spacer (IGS) between the 16S and 23S rRNA genes, growth rate,
and indole acetic acid production, revealed their significant, site-dependent genomic diversity. Among these bacteria, nine
IGS genotypes were identified with two endonucleases. They were distributed into five divergent lineages by sequence analysis
of each IGS representative strain, i.e., (1) comprising IGS genotypes I, II, III, and reference Bradyrhizobium yuanmingense; (2) with genotype IV and strains of unclassified bradyrhizobia genomic species; (3) including genotypes V, VI, and Bradyrhizobium liaoningense; (4) with IGS genotype VII and Bradyrhizobium elkanii strains; and (5) comprising IGS genotypes VIII, IX, and different Ensifer genus bacteria. Host-specificity test revealed that all rhizobia-nodulated soybean and cowpea and only part of them formed
nodules on Arachis hypogeae and Cajanus cajan. The great diversity of soybean nodulators observed in this study emphasises that Indian soil is an important reservoir of
nitrogen-fixing rhizobia. 相似文献
18.
Abisoye Ojo Olajire Fagbola Olubukola Babalola 《Archives of Agronomy and Soil Science》2013,59(3):371-380
Nodule formation in legumes is a process that starts with root infection by rhizobia. The present study assessed the population and infectivity of the indigenous rhizobial strains in rainforest soils of Nigeria. Soils were collected from three sites – Idi-Ayunre, Orile-Ilugun (OI) and the University of Ibadan Teaching and Research Farm (UITRF) – and analysed for physico-chemical properties and rhizobial population. Soybean varieties TGx1448-2E and TGx1456-2E and a cowpea variety IT89KD-288 were planted as trap crops on each of the soils, and rhizobia were isolated from their nodules. Infectivity assay was conducted using eight varieties of soybean and a cowpea variety. Most probable number estimate of the rhizobial population showed that the UITRF had significantly higher rhizobial population than the other two locations. OI and the UITRF soils planted with TGx1448-2E had significantly higher nodules and number of strains than other treatments. Among the 70 slow-grower strains isolated, only nine were infective. Three of the nine strains – IDC8, TRC2 and OISa-6e – nodulated at least seven of the eight soybean varieties used for infectivity test. Indigenous rhizobial infectivity of the studied locations was low, and cultivation of grain legume may require rhizobial inoculation for high productivity. 相似文献
19.
The ability of 4 strains of Rhizobium trifolii to compete with naturalized strains in nodulating Trifolium subterruneum cv. Mt Barker and cv. Woogenellup was assessed at 5 sites in New South Wales. The populations of naturalized rhizobia at these sites ranged from 4 × 106 rhizobia/g to one where no rhizobia were detected. The introduced strains were inoculated singly or as mixed strain inocula onto seed of the host at 2 × 106 rhizobia/seed. There were marked differences in competitive ability between the strains but these differences were modified by the host cultivar and the site.At the R. trifolii-free site the inoculum strain formed 100% of the nodules in the 1st yr; by the second year serologically unrelated strains had invaded the plots and these formed almost all of the nodules in the 3rd yr. At the site where competition was greatest (4 × 106 naturalized rhizobia/g), there were no differences in the competitive abilities of the strains in the first year but at all other sites WU95 was superior whether used as a single strain or in a mixed strain inoculum. In these sites also the proportion of nodules formed by the inoculum strains declined markedly by the 2nd yr. 相似文献
20.
Odair Alberton Glaciela Kaschuk Mariangela Hungria 《Soil biology & biochemistry》2006,38(6):1298-1307
Biological nitrogen fixation plays a key role in agriculture sustainability, and assessment of rhizobial diversity contributes to worldwide knowledge of biodiversity of soil microorganisms, to the usefulness of rhizobial collections and to the establishment of long-term strategies aimed at increasing contributions of legume-fixed N to agriculture. Although in recent decades the use of molecular techniques has contributed greatly to enhancing knowledge of rhizobial diversity, concerns remain over simple issues such as the effects of sampling on estimates of diversity. In this study, rhizobia were isolated from nodules of plants grown under field conditions, in pots containing soil, or in Leonard jars receiving a 10−2 or a 10−4 serially-diluted soil inoculum, using one exotic (soybean, Glycine max) and one indigenous (common bean, Phaseolus vulgaris) legume species. The experiments were performed using an oxisol with a high population (105 cells g−1 soil) of both soybean rhizobia, composed of naturalized strains introduced in inoculants and of indigenous common-bean rhizobia. BOX-PCR was used to evaluate strain diversity, while RFLP-PCR of the ITS (internally transcribed spacer) region with five restriction enzymes aimed at discriminating rhizobial species. In both analyses the genetic diversity of common-bean rhizobia was greater than that of soybean. For the common bean, diversity was greatly enhanced at the 10−4 dilution, while for the soybean dilution decreased diversity. Qualitative differences were also observed, as the DNA profiles differed for each treatment in both host plants. Differences obtained can be attributed to dissimilarity in the history of the introduction of both the host plant and the rhizobia (exotic vs. indigenous), to host-plant specificity, rhizobial competitiveness, and population structure, including ease with which some types are released from microcolonies in soil. Therefore, sampling method should be considered both in the interpretation and comparison of the results obtained in different studies, and in the setting of the goals of any study, e.g. selection of competitive strains, or collection of a larger spectrum of rhizobia. Furthermore, effects of sampling should be investigated for each symbiosis. 相似文献