Occurrence of nodulation in unexplored leguminous trees native to the West African tropical rainforest and inoculation response of native species useful in reforestation

Despite the abundance and diversity of timber tree legumes in the West African rainforest, their ability to form nitrogen-fixing nodules in symbiosis with rhizobia, and their response to rhizobial inoculation, remain poorly documented. In the first part of this study the occurrence of nodulation was determined in 156 leguminous species growing in six natural forest areas in Guinea, mostly mature trees. In the second part, an in situ experiment of rhizobial inoculation was performed on eight selected tree species belonging to three genera: Albizia, Erythrophleum and Millettia. Of the 97 plant species and 14 genera that had never been examined before this study, 31 species and four genera were reported to be nodulated. After 4 months of growing in a nursery and a further 11 months after transplantation of plants to the field, we observed a highly significant (P < 0.001) and positive effect of inoculation with Bradyrhizobium sp. strains on the growth of the eight tree species tested. The importance of determining the nodulation ability of unexplored local trees and subsequently using this information for inoculation in reforestation programmes was demonstrated.     

我国豆科树种结瘤调查

据国内资料报道,我国豆科树种约94属763种,已调查过结瘤状况的有含羞草亚科的123种(包括近几年来从国外引种的54种)、蝶形花亚科的211种和苏木亚科的70种,其中可以结瘤的有含羞草亚科的116种、蝶形花亚科的207种和苏木亚科的18种。含羞草亚科中的2种、蝶形花亚科中的3种均有结瘤和不结瘤的报道。     

我国豆科树种结瘤调查(续)

据国内资料报道,我国豆科树种约94属763种,已调查过结瘤状况的有含羞草亚科的123种(包括近几年来从国外引种的54种)、蝶形花亚科的211种和苏木亚科的70种,其中可以结瘤的有含羞草亚科的116种、蝶形花亚科的207种和苏木亚科的18种。含羞草亚科中的2种、蝶形花亚科中的3种均有结瘤和不结瘤的报道。     

Actinomycetous root nodules in angiosperms of Pakistan

Summary In a survey, out of the nineteen genera of non-leguminous angiosperms that are already reported to bear actinomycete-induced nitrogen-fixing root nodules from various parts of the world, the species of seven genera (Alnus, Elaeagnus, Hippophaë, Coriaria, Datisca, Rubus and Casuarina) have been located in Pakistan and checked for nodulation. All the investigated species of the these genera, except those of Rubus and some of the introduced species of Casuarina, were found to bear nodules. In all 12 species belonging to six genera of five families have been recorded to bear actinorhizal nodules in Pakistan.     

Rhizobial symbiosis on Venezuelan savannas

Summary An extensive study of the leguminous plants growing on Venezuelan savannas was made. Of 127 species examined, 109 were nodulated, with 73 species in the Papilionoideae. 71 species in 17 genera are new records of nodulation. Most of the non-nodulated species were in the Caesalpinioideae, and non-nodulation was correlated with brown coloured roots. Some environmental factors involved in the establishment of the legume-Rhizobium association are discussed. These observations on nodulation represent 13 per cent of the total Leguminosae flora of Venezuela.     

Studies on tree legumes

Twenty five species of tree legumes, belonging to genera Acacia, Albizzia, Bauhinia, Colophospermum, Dichrostachys, Leucaena, Peltophorum, Pithecolobium and Prosopis were examined for nodulation under pot culture conditions using unsterilized soil. Out of these, only nineteen tree-legumes nodulated. It was interesting to note that all the three species of Bauhinia and one each of Acacia, Colophospermum and Peltophorum did not nodulate both at Jodhpur and Delhi. Inoculation of tree legumes with their own rhizobial isolates, improved nodulation under sterilized conditions.     

Nodulation of native woody legumes in Hong Kong, China

Woody legumes can play an important role in forest restoration on degraded land but the knowledge of woody legumes has lagged behind their uses. This study is a pioneer investigation to explore the ability of native woody legumes to form root nodules and fix nitrogen in Hong Kong. Nine sites of different habitat types were surveyed during both wet and dry seasons for two years. Young plants of woody legumes along studied transects were excavated. The patterns of nodulation and nodule morphology were recorded and the nitrogen fixing ability was tested by acetylene-reduction-assay. Twenty-eight species in 16 genera were examined, of which 20 species were nodulating and eight non-nodulating, including all six species in the Caesalpinioideae. Five species were new records to the world’s nodulation inventory. Bowringia callicarpa was a new species and genus examined, which was non-nodulating. The overall nodulation pattern was consistent with previous studies. Nodulation was more profuse in some shrub species while inconsistent in most tree species. Species with higher proportion of nodulated individual plants also tended to have more nodules in each plant. Spherical nodules were common in shrub and woody climber species whilst tree species usually had woody indeterminate nodules. Seasonal difference in the amount of senescent nodules was noted in most species. All the nodules tested by acetylene-reduction-assay were effectively nitrogen-fixing, with nitrogenase activity ranging from 4 μmol C₂H₄ g^?1 h^?1 to 20 μmol C₂H₄ g^?1 h^?1, which was comparable to other tropical tree species. The findings in nodulation pattern and nitrogen fixing ability of these species are essential in their application in forest restoration on degraded lands.     

Additions to the known nodulating species ofLeguminosae

Summary Observations have been made on the nodulation of species ofLeguminosae. Nodulation is recorded for 137 previously unlisted species in 24 genera, including 8 previously unlisted genera, all species being indigenous in Western Australia.     

Patterns of gonad structure in hermaphroditic gobies (Teleostei Gobiidae)

Synopsis Hermaphroditism has been reported for a small number of gobiid fishes, but the extent of this sexual pattern within the family is not known. Gonad structure was examined in one or more species from twenty-one gobiid genera. No evidence of hermaphroditism was found in the species selected from 14 genera. Laboratory studies supported the conclusion of gonochorism for the examined species in four of them:Asterropteryx, Bathygobius, Gnatholepis, andPsilogobius. Currently, the absence of precursive testicular tissues associated with the ovary in females, in conjunction with no retained ovarian features in the testes of males, appear to be reliable indicators of a gonochoristic sexual pattern in gobiid fishes. Evidence for hermaphroditism was observed in seven genera:Eviota, Trimma, Fusigobius, Lophogobius, Priolepis, Gobiodon, andParagobiodon. Protogyny was experimentally confirmed inE. epiphanes, and the gonad structure in another nine of ten species ofEviota suggested either protogyny or protogynous tendencies. With the exception ofGobiodon andParagobiodon, which exhibited similar gonadal structure, ovarian and testicular structure varied considerably among the hermaphroditic genera examined, both with regard to the configuration and to the degree of development of ovarian and testicular tissues, or testicular tissue precursors. Findings of this study indicate that hermaphroditic gonad structure will prove to be a useful trait in determining evolutionary relationships within the Gobiidae.     

From North to South: A latitudinal look at legume nodulation processes

Legumes and some nodulation processes evolved about 55–60 Ma. Since then they have radiated from their origin at either side of the Tethys seaway, to high latitudes in both the northern and southern hemispheres. In many cases this has involved different tribes and genera, and different nodule processes, but with the common feature that almost all legumes in the higher latitudes are potentially nodulated and, with the exception of some herbaceous species of Chamaecrista, nodulated caesalpinioid legumes are rare. This is not true of tropical regions where all three sub-families are found, with many of their species lacking the ability to nodulate. Whether or not this is related to the availability of combined nitrogen is a matter of current discussion. This review will consider the range of nodulation phenotypes (infection, morphology, structure) and show how many of these are confined to one or other hemisphere. How this might relate to the different genera and species of endophytic (nitrogen fixing) rhizobia in relation to soil conditions will also be discussed. Better knowledge of the wide variation in nodulation parameters is important for understanding the ecology of different regions and for management purposes. Nodule characters are of great potential use in defining taxonomic groupings in legumes.     

Soil and environmental factors related to nodulation in Cowania and Purshia

Summary Nitrogen fixing trees and shrubs may be useful in revegetation efforts. The possibility that soil and environmental factors may influence a soil's capability to produce nodulated seedlings was explored.Purshia tridentata andCowania mexicana var. Stansburiana seedlings were grown in greenhouse trials using ten soils from native sites for each of the two genera. Treatments included a control and a six mmole nitrogen amendment as NH₄NO₃ for both surface and subsurface samples. Nodulation was often sparse for seedlings grown in surface collected samples. Although nodulation was usually better in subsoil samples, even some subsoils produced few or no nodules. Nitrogen additions inhibit nodulation and although soil nitrogen may be inhibitory in some unamended surface soils it is probably not a general cause of sparse nodulation. Nodule masses showed the same trends as nodule number but varied less with treatment and depth of soil source. Seedlings compensated for sparse nodulation with an increase in mass per nodule. Incidence of nodulation was related to some soil and environmental factors. Multiple regression analysis explained a substantial portion of nodulation variability. Soils from lower elevations with less precipitation did not produce well nodulated seedlings even in well watered greenhouse trials. Micronutrient cations, potassium, and phosphorus are positively correlated with nodulation incidence. The two genera were generally similar in nodulation responses to soil and environmental factors.Support for portions of this study was provided by the National Science Foundation (PCM-8204885). Any opinions, findings conclusions or recommendations expressed are those of the authors and do not necessarily reflect the views of the sponsor. Oregon Agricultural Experiment Station technical paper number 7293.     

云南胶园耐荫豆科绿肥资源调查与评价

本文系统调查了云南主要植胶区开割胶园中豆科绿肥资源种类、地理分布、结瘤情况等,并对绿肥资源现状与结瘤特征进行了评价。研究结果表明,云南胶园现有耐荫豆科绿肥22属42种。绿肥虽然分布广泛,但植株个体数量少;生活型以草本、藤本、亚灌木为主;属中种类少;基本未被开发利用。所调查豆科绿肥结瘤率达88.2%,根瘤大且数量多,形状以球形、椭球形为主,颜色多为粉红、红色。     

Effect of certain soil conditions on nodulation ofAcacia spp.

Summary Growth and nodulation ofAcacia spp. in sand increased with increase in soil moisture to an optimum at 15 per cent soil moisture and this agreed with the occurrence of these species in the more moist sites reported by other workers. TheAcacia species grew and produced effective nodules at up to 35°C and this is the highest temperature for nodulation so far recorded. It indicated adaptation of these species to the warm and dry conditions of the fields. Soil reaction affected nodulation more than it affected plant growth. At pH 5–5.5 nodulation was absent while plant growth was as good as at pH 6.5–7.0 which was the optimum level for both growth and effective nodulation. The latter were reduced at pH 8.5–9.0 and therefore the alkaline reaction of the soils in Northern Sudan may be a factor influencing growth of Acacia in that region.     

A survey of hemoparasite infections in free-ranging mammals and reptiles in French Guiana

Blood smears of 1,353 free-ranging mammals (35 species) and 112 reptiles (31 species) from French Guiana were examined for hemoparasites. Parasites from 3 major groups were recorded: Apicomplexa (including hemogregarines, piroplasms, and Plasmodium spp.), Trypanosomatidae, and Filaroidea. Fifty percent of the individuals (86% of the species) were infected by parasites from at least 1 group. Hemogregarines, identified as Hepatozoon sp., infected numerous snakes with high prevalences (30-100%); infection is reported for the first time in 5 host genera of snakes: Clelia, Oxybelis, Pseustes, Rhinobotryum, and Bothriopsis. Infections were also observed in 4 marsupial species and 1 rodent. Hepatozoon spp. recorded in Didelphis albiventris (Marsupialia) and Coendou prehensilis (Rodentia) may be new species. Plasmodium sp. were observed in 2 snake species, Dipsas indica (Colubridae) and Bothrops atrox (Viperidae). Plasmodium brasilianum was recorded in all 5 primate species examined. Piroplasms were observed in all mammal orders except primates. Large terrestrial rodents were the main hosts of members of the Babesidae; 42% of Myoprocta acouchy, 36% of Dasyprocta agouti, and 44% of Agouti paca were infected. Trypanosomes were common in mammals and were recorded in 70% of the examined genera. Trypanosoma cruzi-like infections were reported in 21 mammal species, including sloths, rodents, carnivores, and primates. Microfilariae were also widespread, with higher prevalences in sloths, anteaters, and porcupines (>40% of the individuals infected) and in tamarins (95% infected). This survey highlights some potential anthropozoonotic risks due to the recent further evidence of Plasmodium brasilianum and P. malariae as a single species and to the increased diversity of hosts for Trypanosoma cruzi.     

The Sesbania Root Symbionts Sinorhizobium saheli and S. teranga bv. sesbaniae Can Form Stem Nodules on Sesbania rostrata, although They Are Less Adapted to Stem Nodulation than Azorhizobium caulinodans

Sesbania species can establish symbiotic interactions with rhizobia from two taxonomically distant genera, including the Sesbania rostrata stem-nodulating Azorhizobium sp. and Azorhizobium caulinodans and the newly described Sinorhizobium saheli and Sinorhizobium teranga bv. sesbaniae, isolated from the roots of various Sesbania species. A collection of strains from both groups were analyzed for their symbiotic properties with different Sesbania species. S. saheli and S. teranga bv. sesbaniae strains were found to effectively stem nodulate Sesbania rostrata, showing that stem nodulation is not restricted to Azorhizobium. Sinorhizobia and azorhizobia, however, exhibited clear differences in other aspects of symbiosis. Unlike Azorhizobium, S. teranga bv. sesbaniae and S. saheli did not induce effective stem nodules on plants previously inoculated on the roots, although stem nodulation was arrested at different stages. For Sesbania rostrata root nodulation, Sinorhizobium appeared more sensitive than Azorhizobium to the presence of combined nitrogen. S. saheli and S. teranga bv. sesbaniae were effective symbionts with all Sesbania species tested, while Azorhizobium strains fixed nitrogen only in symbiosis with Sesbania rostrata. In a simple screening test, S. saheli and S. teranga bv. sesbaniae were incapable of asymbiotic nitrogenase activity. Thus, Azorhizobium can easily be distinguished from Sinorhizobium among Sesbania symbionts on the basis of symbiotic and free-living nitrogen fixation. The ability of Azorhizobium to overcome the systemic plant control appears to be a stem adaptation function. This last property, together with its host-specific symbiotic nitrogen fixation, makes Azorhizobium highly specialized for stem nodulation of the aquatic legume Sesbania rostrata.     

The Criconematidae of the British Isles

A total of 2622 soil samples collected throughout the British Isles was examined for nematodes belonging to the family Criconematidae. Twenty-eight species were found representing nine genera, twenty-two of these species being reported for the first time. Only one species previously reported was not found. An analysis of the relationship between eleven of the most common species and biotic and abiotic factors showed vegetation to be of paramount importance.     

中国帕米尔高原根瘤菌-豆科植物共生资源调查

对帕米尔高原进行了根瘤菌——豆科植物共生资源的调查与收集,分析了根瘤的特征和根瘤菌的抗逆性。共采集到11属22种豆科植物,除菜豆、昆仑锦鸡儿、豇豆和白花草木樨等4种豆科植物未见结瘤外,其它豆科植物均能结瘤,其中帕米尔扁蓿豆、美丽棘豆、毛序棘豆、金毛脬萼黄芪等4种为新发现的结瘤豆科植物。共收集到8属18种豆科植物的根瘤样品250份,发现根瘤数量相对较少,颜色以白色或褐色为多,形状多样,多着生于主根、侧根的上部。通过对109株根瘤菌的抗逆性分析,获得一些具有耐低温和耐盐碱能力的优良菌株。     

CHROMOSOME NUMBERS IN COMPOSITAE VIII: HELIANTHEAE

One hundred and ninety-three new counts are reported for the tribe Heliantheae of Compositae, mostly based on determinations of meiotic material, including first counts for the genera Adenothamnus, Chrysogonum, Enceliopsis, Guardiola, Isocarpha, Lipochaeta, Otopappus, and Oyedaea, as well as first counts for 66 species. The original counts are discussed in relation to those previously reported for the tribe, by genera and subtribe. Two-thirds of the approximately 150 genera and more than a third of the roughly 1500 species have now been examined. The incomplete knowledge of generic relationships in the tribe often make the interpretation of these chromosome numbers difficult. Three observations are documented and discussed: (1) genera with low chromosome numbers are few; (2) genera with aneuploid series are abundant; and (3) the original basic chromosome number in the tribe is probably in the range of x = 8 to x = 12.     

Associations Among Rhizobial Chromosomal Background, nod Genes, and Host Plants Based on the Analysis of Symbiosis of Indigenous Rhizobia and Wild Legumes Native to Xinjiang

The associations among rhizobia chromosomal background, nodulation genes, legume plants, and geographical regions are very attractive but still unclear. To address this question, we analyzed the interactions among rhizobia rDNA genotypes, nodC genotypes, legume genera, as well as geographical regions in the present study. Complex relationships were observed among them, which may be the genuine nature of their associations. The statistical analyses indicate that legume plant is the key factor shaping both rhizobia genetic and symbiotic diversity. In the most cases of our results, the nodC lineages are clearly associated with rhizobial genomic species, demonstrating that nodulation genes have co-evolved with chromosomal background, though the lateral transfer of nodulation genes occurred in some cases in a minority. Our results also support the hypothesis that the endemic rhizobial populations to a certain geographical area prefer to have a wide spectrum of hosts, which might be an important event for the success of both legumes and rhizobia in an isolated region.     

几种具纤毛分生孢子的腔孢菌

本文报道了河北省具纤毛(setulae)分生孢子的腔孢菌(Coelomycetes)5种,它们隶属于多毛孢属(Polynema Lev.),星毛孢属(Stauronema H.Sydow,Sydow ＆Butler),刺杯毛孢属(Dinemasporium Lev.)和双毛壳孢属(Discosia Lib.)。其中多毛孢属和星毛孢属系国内新记录属。记载了一新种中国多毛孢(Polynema sinense w.-P.Wu)和一中国新记录种甘蔗星毛孢(Stauronema sacchari H.Sydow,Sydow ＆Butler)。在刺杯毛孢属和双毛壳孢属内共鉴定出3个种,它们是槭刺杯毛孢(Dinemasporium acerinum Peck),刚毛刺杯毛孢(Dinemasporium strigosum(Pets.:Ft.)Sate.)和双毛壳孢(Discosia artocreas(Tode:Fr。)Ff.)。文中对这些种进行了详细描述,新种有拉丁文描述。研究标本保藏于河北省科学院生物研究所。