Dissertations / Theses on the topic 'Dieffenbachia'

Xanthomonas campestris pv dieffenbachiae, (x. C. D. ) pathogene de plantes de la famille des aracees est un facteur limitant de la production d'anthurium dans de nombreuses regions tropicales. Il appartient a l'espece campestris qui regroupe plus de 140 pathovars distincts par leur hote d'origine. Afin de clarifier la position taxonomique de ce groupe et d'etudier sa variabilite interne nous avons utilise deux sondes: la sonde rarn 16+23s d'e. Coli marquee a l'acetylaminofluorene et une sonde repetee isolee du genome de x. Campestris pv. Dieffenbachiae, is 1051. Par ribotypage cinquante-six souches de x. Campestris pv. Dieffenbachiae representatives de la variabilite de ce pathovar ont ete analysees. Huit profils ont ete obtenus: 4 correspondent aux souches d'anthurium, les 4 autres representent des souches d'autres aracees. Le profil majoritaire regroupe 34 des 43 souches d'anthurium analysees. Ces profils ont ete compares a ceux de 4 souches de pseudomonas, 3 souches de xylophilus ampelinus, 28 souches de differentes especes de xanthomonas, et 156 souches appartenant a 14 pathovars de l'espece campestris. Des profils majoritaires se degagent de l'analyse des souches de x. Albilineans, x. Campestris pv begoniae, malvacearum et manihotis. Une analyse de ces profils fait apparaitre le regroupement des pathovars de l'espece campestris. L'etude de la variabilite genetique a ete approfondie avec la sonde is 1051. Cette sonde est une sequence d'insertion de la famille des is 5. C'est un element de 1158 pb borne par 2 sequences repetees inversees de 15 pb. Les profils rflp obtenus permettent de distinguer les origines geographiques et les plantes hotes. L'is 1051 est un element genetique assez conserve au sein des xanthomonas. Des profils d'hybridation ont ete obtenus avec des souches d'autres especes (x. Fragariae, x. Axonopolis, x. Oryzae) et avec des souches appartenant a 11 pathovars de l'espece campestris. La detection de la bacterie a ete etudiee par voies serologique et moleculaire. Un serum polyclonal a ete produit. Il detecte en elisa les souches de x. Campestris dieffenbachiae d'anthurium avec une sensibilite de 10#4b/ml. Des oligonucleotides internes a is 1051 ont ete testes pour la detection par pcr. Le couple y5 y9 amplifie 1 a 2 ng d'adn de souches isolees d'anthurium provenant d'origines geographiques differentes et representatives des differents profils d'hybridation

碩士
國立中興大學
園藝學系
90
Shoot regeneration through callus culture was induced successfully from young expanded leaves of Dieffenbachia maculata ‘Rudolph Roehrs-86M1’in vitro. Young leaves were cut into 1 ×1cm pieces and surface sterilized in 0.5% sodium hypochlorite for 10 min followed by washing with sterile distilled water. The contamination was controlled under 25%. Leaves were cultured on the medium containing 1/2 MS, sugar 20g/l, agar 6g/l, BA 5 mg/l and NAA 0.5 mg/l and were induced more callus . Shoot proliferated when callus explant of 5mm in cubic was cultured on the medium containing 1/2 MS, agar 6g/l, sugar 20g/l, BA 5 mg/l and NAA 0.125 mg/l. Shoot longer than 2.5 cm rooted well when shoot base was coated with NAA 0.1%. There was 50% or 66.7% of callus proliferating shoot, when callus of 5mm×5mm was irradiated 4 Gy γ-ray once or twice, respectively. However, callus of 10mm×10mm was irradiated once, the rate of shoot proliferation increased to 76.8%. And there was 50% of callus proliferating shoot when irradiated twice.

Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeiros
Dieffenbachia picta Schott. (Araceae), conhecida no Brasil as “comigo ninguém pode” é uma planta ornamental cujas propriedades tóxicas do suco do caule da planta quanto em contato com a boca ou aspirado são responsáveis por casos de intoxicação em crianças e animais domésticos.

博士
國立臺灣大學
園藝學研究所
94
In this research the influence of pathogen-free explant preparation on aseptic culture and shoot proliferation in Dieffenbachia ‘Starshine’ was study. Using different sizes of apical meristem as initial pathogen-free explants and cultured on solidified Murashige and Skoog (MS) medium with 1mg/L NAA and 1mg/L TDZ for 15 weeks. The 20% of survival rate were obtained from the minimum size (0.1x0.25mm) of shoot tip explant, and 12.3 shoots were regenerated from the larger size (0.9x1.2mm) of shoot tip explant during primary aseptic culture. Moreover, tests used 4 sizes of axillary bud meristem as initial pathogen-free explant for primary aseptic culture. Result demonstrates that removed 3 or 4 coleoptiles of axillary bud explant, gave the survival rate of 30-35%. But, on average, 11.2 shoots regenerated from excided 1 coleoptile of axillary bud explant. These results indicated using apical meristem as pathogen-free explant gave optimize information for primary aseptic culture in Dieffenbachia ‘Starshine. Furthermore, pretreatment of stock plants with 6-week drought stress and further dissected axillary bud under aseptic condition as pathogen-free explants for primary aseptic culture. Results show the explant preparation procedure gave the high survival rate was 80-92.5% from removed 2-4 coleoptiles of axillary bud explant. This result suggests using axillary bud explant dissection and treating with drought stress could escape contamination from the interior contaminants. At the same procedure, more than 90% of survival rate was observed in axillary bud explants for successfully established of primary aseptic culture between tested cultivars（D. cv. Rudolph Roehrs and D. cv. Jupiter）. In addition, the influence of culture methods and TDZ concentration on shoot multiplication were investigated. For shoot multiplication, concentration of 1, 5, and 10mg/L TDZ in the liquid culture were found that shoot yields have a significant effect achieved 5-6 folds. While, 2-nodal explant was cultured in liquid medium only obtained 2 folds of multiplication rate, but compared to solid culture, the regenerated shoots were more rapid growth and uniformity during subculture. This result suggests that liquid culture can significantly enhance axillary shoot proliferation from stock stem explants and 2-nodal explants for mass multiplication in Dieffenbachia seedlings. A rapid and efficient procedure is described for mass multiplication of microshoots using temporary immersion system (TIS) in dieffenbachia (Dieffenbachia ‘Starshine’). Multiple shoot proliferation was induced from 2-nodal and stock-stem explants on Murashige and Skoog (MS) media supplemented with 1 mg/L NAA and 0.1-5.0 mg/L thidiazuron (TDZ) or BA. Especially, the 2-nodal or stock-stem explants cultured under TIS on 5mg/L TDZ enriched medium had the highest shoot yield which was 24.5 and 59.2, respectively, the multiplication rate increased by 3.3-8 folds, over that obtained from conventional solid support systems. Therefore, the scheme for the rapid microshoot propagation of dieffenbachia using temporary immersion system had commercial efficiency. In addition, elongated multiple shoots after acclimatization, taken from the temporary immersion system, pretreated with 500mg/dm3 NAA then were cut and planted in plug with soilless mix under mist propagation condition to prevent desiccation. Survival was investigated after 30 days, microshoots taller than 3.0㎝ had the highest survival rate, which achieved 80-100%. Moreover, the shoot cluster was segmented into 1/4 or 1/2 section as propagules; the survival rate was 83.3-100%. In this production scheme, shoot cluster could be established a system of superior stock-plant for use in dieffenbachia cuttage. A method for the somatic embryogenesis and subsequent plant regeneration for Dieffenbachia ‘Tiki’ hybrids was described. Male inflorescence explants isolated from spadix of flowering plants cultured in vitro, formed embryogenic calli on surfaces of inflorescence axis within eight weeks of culture on full-strength Murashiage and Skoog (MS) medium with 4-6 mg/L 2,4-D. Somatic embryogenesis and embryoid were induced using a modified half-strength MS combination of 2 % sucrose with 1 % glucose, 0.18 % Gelrite for the basal medium, supplemented with 4.0 to 5.1 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg/L Kinetin. Male inflorescence explants transfer to modified half-strength MS basal medium with 0.5mg/L Kinetin and 4mg/L 2,4-D（or 2-4mg/L Dicamba）resulted in somatic embryogenesis at frequencies of 45-72.1% with an average of 13.3-22.2 somatic embryos per responding explant. Furthermore, at the same culture condition, male inflorescence explants were cultured onto half-strength MS basal medium with 4mg/L 2,4-D and 0.5-1.0mg/L Thidiazuron（TDZ） for embryogenesis. TDZ was found to increase the somatic embryogenesis frequencies to 100% with an average of 32.1-38.2 somatic embryos per responding explant. At the same condition, a few somatic embryos developed into complete plantlets. In this study, we are the first to report somatic embryogenesis in Dieffenbachia ‘Tiki’ and the conversion of somatic embryos to greenhouse-established plant. A regeneration system for improving the efficiency of somatic embryogenesis and emblings recovery from male inflorescences and somatic embryos of Dieffenbachia ‘Tiki’ were described. The highest percentage (100%) of primary somatic embryogenesis were achieved, and the highest yield of mature primary embryos were 75.5 on the half strength modified Murashige and Skoog（MS）medium with 2mg/L Dicamba and 0.5mg/L TDZ from male inflorescence explants. The results indicated that combination of Dicamba (2mg/L) and TDZ (0.5mg/L) significantly promoted high-efficiency multiplication of mature primary embryos in Dieffenbachia ‘Tiki’. Furthermore, the mature embryos of primary somatic embryogenesis were used as initial secondary explants for the induction of repetitive somatic embryogenesis. On the same culture medium supplemented with 2mg/L Dicamba and 0.5-1.0mg/L TDZ, the highest frequency (100%) of secondary embryo formation was obtained after 8-week subculture, and the highest number of mature secondary embryos per explant achieved 33.0-34.3 after 13-week subculture. Consequently, the same medium compositions were suitable for efficient repetitive somatic embryogenesis and multiplication of secondary embryos. In addition, emblings conversion of mature secondary embryos was investigated. The green secondary embryos of 4-5mm in size and the age of 8-10 weeks were used as explants, and cultured on half strength modified MS supplemented with 150mL/L coconut milk for somatic embryo conversion. The highest converted frequency of somatic embryo were 73.3%, and the number of converted emblings per explant reached 7.8 at 0.5% glucose and 1.0mg/L TDZ combination. Plantlets conversion from embryo was successfully acclimatized to greenhouse conditions. This technique could have significant industry application in dieffenbachia micropropagation, based on it has high efficiency of somatic embryo formation and high level of plant recovery.

碩士
國立嘉義大學
園藝學系研究所
94
A procedure for the induction, proliferation, emblings conversion of somatic embryo and axillary buds multiplication in Dieffenbachia ‘Anna’ was described. The male inflorescence explants were isolated and cultured on 1/2 Murashige and Skoog (MS) medium with 1% glucose, 2% sucrose, 3% Gelrite as the basal medium. Embryogenesis callus was induced and had the best growth index on medium with 4 mg/L Dicamba and 1-2 mg/L Thidiazuron (TDZ), the percentage of forming somatic embryo were 69.4-90.4% with an average of 41.7-43.7 somatic embryos per explant. Furthermore, at the same culture condition, primary somatic embryo explants were cultured on 1/2 MS basal medium with 1-2 mg/L 2,4-D or 1-2 mg/L Dicamba and 1-2 mg/L Dicamba combined with 2 mg/L TDZ, respectively, the percentage of secondary somatic embryogenesis was 100%. Secondary somatic embryos (SSE) could be obtained with an average of 30-35 embryos on basal medium supplemented with 1 or 4 mg/L Dicamba and 2 mg/L TDZ. At the same test, SSE could be reached with an average of 30 embryos on basal medium added 2-4 mg/L TDZ and 2% glucose. Moreover, the emblings formation of mature somatic embryo was at a frequency of 80% with an average 3.1 emblings on 1/2 MS basal medium supplemented with 150 mL/L coconut milk and 2% glucose, those emblings developed into complete plantlets at the same culture condition. At the same tests, the basal medium with 2-4 mg/L GA3 was found to significantly accelerate SSE developed to coleoptilar stage, and then promote the sheaths elongation. Furthermore, axillary buds multiplication via temporary immersion system (TIS) was invesgated. The shoot proliferation was induced on MS medium supplemented with 1 mg/L NAA and 1mg/L BA, results indicated the shoot yield was 6.1 under 30 min/6hr immersion time, and the basal suitable medium volume was 350 mL. Shoot proliferation crate be obtained from >5cm nodal and stock-stem explants was 5.4-5.5. In this production scheme, a mass-production system could be established from axillary multiplication for Dieffenbachia industry.

碩士
中華醫事科技大學
生物醫學研究所
98
Xanthomonas is a Gram-negative bacterium and one of the most important phytopathogenic bacteria in the world, which causes many agricultural loss. As Xanthomonas axonopodis pv. dieffenbachiae (Xad) and Xanthomonas oryzae pv. oryzae (Xoo) affected many economic plants in Taiwan. In order to identify Xad and Xoo at the early stage of infection, we plan to develop a rapid detecting technique based on the DNA sequences of gyrB、virD4、rpoD and Lytic enzyme. We cloned several DNA fragments from different species of Xad、Xoo、Xcm、Xav、Xcc and Xac, and the bioinformatics analysis of Multiple Sequences Alignment displayed the diversity sequences. The specific primer-pairs were designed for the PCR identification of Xad and Xoo by the diversity sequences. On the detection of Xad, the PCR detection results of XAD-gyrB、XAD-virD4 and XAD-LE revealed the specificity will be 100％. The sensitivity of XAD-gyrB the will be 40 pg-4 pg DNA or 103 cfu-102 cfu. The sensitivity of XAD-virD4 will be 2 pg-200 fg DNA or 102-101 cfu. The sensitivity of XAD-LE will be 30 pg-3 pg DNA or 102 cfu-101 cfu. On the detection of Xoo, the PCR detection results of XOO-gyrB、XOO-rpoD the specificity will be 100％. The sensitivity of XOO-gyrB the sensitivity will be 30 pg-3 pg DNA or 102 cfu-101 cfu. The sensitivity of XOO-rpoD the sensitivity will be 40 pg-4 pg DNA or 103 cfu-102 cfu. Moreover, we used Multiplex-PCR method to detect Xad or xoo. The combination of XAD-virD4、XAD-gyrB and XAD-LE was used to detect Xad and the combination XOO-gyrB and XOO-virD4 was used to detect Xoo. The results revealed the specificity of these combinations will be 100% for detection. Accordingly, the PCR and multiplex PCR are useful and reliable methods for the detection. This technique could be a diagnostic tool for screening and monitoring of Xanthomonas axonopodis pv. dieffenbachiae (Xad) and Xanthomonas oryzae pv. oryzae (Xoo).

碩士
國立中興大學
植物病理學系
89
Isolation, Detection and Control of Xanthomonas axonopodis pv. dieffenbachiae Causal Organism of Bacterial Blight of Anthurium ABSTRACT At present anthurium cultivation area is about 97ha in Taiwan. Bacterial blight disease on anthurium showing leaf symptoms of necrotic lesions that surrounded by yellow halo were first found at Puli, Nantou in 1991, and a leaf yellow type of symptoms of the disease was observed in the southern part of Taiwan in the following year. The disease is now spread to most of anthurium fields in Taiwan. In this study, efforts were paid on, identification, detection and control of the disease. Selected primers were used to find specific DNA markers of Xanthomonas axonopodis pv. dieffenbachiae (Xad) by using random amplified polymorphic DNA (RAPD). Antagonistic bacteria isolated from leaf surface were used to test for their efficacy on biocontrol. Isolate XadH-2 is the most virulent among 83 strains tested. The lowest concentration needed to cause infection was 104cfu/ml. The pathogen infected into leaf tissue 15th day after spray inoculation. Based on physiological, biochemical and inoculation test, the caused organism was identified as X. axonopodis pv. dieffenbachiae that cause anthurium blight. RAPD analysis for genomic DNA of Xad-2 and comparison with strains and 17 pairs of random primer, it was fount only OPB-1 could amplify a distinct fragment of 565bp. The inserted DNA fragment was digested by EcoR 1. The primers were designed and synthesized by the sequence of the inserted fragment. Detection of all Xad strains all were able to amplify a distinct fragment of 341bp by Bio-PCR. Sensitive test of primer pairs by Bio-PCR, that lowest detection concentration is about 4.6×104cfu/cm2. Antagonistic bacterium No.2, 3, 23, 33 and 36 have potential to control anthurium bacterial blight. By grading analysis of infected leaf area 120 days after test, that No.2, 3, 23, 33, 36, BS002 and three pesticides. Kasugamycin+ copper oxychloride and maneb+ coppersulphate gave good control of the disease. Maneb+ coppersulphate, Kasugamycin+ copper oxychloride, mancozeb and tecloftalam showed better control when using grade analysis of pathogen infected leaf area on 120th day. Using Biolog antagonistic that bacterium No.2 and 36 were identified as Bacillus amyloloquefaciens, No.23 was Bacillus licheniformis and No.3 and 33 were Bacillus subtilis.

碩士
國立臺灣大學
植物病理學研究所
88
A new insertion sequence was successful isolated from Xanthomonas campestris pv. dieffenbachiae（XCD）by applying the entrapment plasmid, pUCD800. The plasmid pUCD800 was introduced into XCD via electroporation. In the presence of sucrose, levansucrase produced by sacB of pUCD800 plasmid and caused XCD population decreased. Restriction enzyme analyses of these plasmids from 186 sucrose-resistant colonies revealed that the majority recovered that in the manner contained insertions in sacBR element of pUCD800（18.8﹪）or show no noticeable change in the structure of pUCD800（38.2﹪）, and 46.77﹪ probably involved gross rearrangement of pUCD800. The new insertion sequence, ISXCD1, ( accession no. AF263433 ) is 1,203 bp in size and contains 38 bp inverted repeats with 11 bp mismatches at its termini. It generated 4-bp target site duplications in sacBR regions of pUCD800 harbored in 15-4 and 27-1 transformants, and carried two overlapping ORFs（orfA and orfB）, with an A7T motif within the overlapping region. The deduced amino acid sequences of orfA and orfB contained a potential helix-turn-helix motif and a D, D(35)E domain of transposases, respectively. ISXCD1 is present about 9-11 copies in the XCD genome according to Southern hybridization. Southern hybridization analyses the distribution of the new IS is widely existed G（-）and G（+）. Sequence analysis of 5 independent genomic copies of IPCR products indicated no preferred insertion site for the new insertion sequence. In H-2 transformant revealed that ISXCD1 exactly inserted into IS1051, and caused a 4 bp target site duplication. For the detection purpose, a PCR primer pair F570/ R1006 was designed based on the nucleotide sequence of the new IS. A minimum of 1.5 pg DNA of purified genomic DNA of XCD was sufficient to amplified a 436 bp PCR-product.

碩士
國立臺灣大學
植物病理學研究所
87
Two pairs of primers for the polymerase chain reaction-based assay were developed for the detection of the causal agent of anthurium blight, Xanthomonas campestris pv. dieffenbachiae (XCD). One of the primer pairs was synthesized according to the sequence of a cloned DNA probe for XCD, and the other was synthesized according to the sequence of the internal transcribed spacer region between the 16S and 23S rRNA genes of XCD. In order to develop cloned DNA probes for XCD, EcoRI or PstI restriction fragments of genomic DNA of XCD were cloned in plasmid pBluescript SK(-). Five XCD-specific transformants were selected based on the results of differential hybridization using digoxigenin-labeled total DNA of XCD and other closely related pathovars of X. campestris as probes. Cloned DNA inserts from the XCD-specific recombinant plasmid were excised, labeled with digoxigenin, used as probes for dot hybridization and Southern hybridization analyses. The probe from clone S10s (2.3 kb in length) showed the best specificity among the five probes, and the primer pair S10f-11/S10r-11 was thus synthesized according to the nucleotide sequence of the cloned insert. Primer pair S10f-11/S10r-11 could specifically amplify a 705 bp-PCR product using DNA template prepared from XCD but not from other pathovars of X. campestris and other bacterial species. In another approach, universal primers targeting conserved sequences flanking the 3'' end of the 16S and the 5'' end of the 23S rRNA genes were synthesized and used to amplify the 16S-23S rDNA internal transcribed spacer of XCD. A 585 bp-PCR product containing spacer region thus amplified was cloned in pCRII for nucleotide sequence determination. Sequences for tRNAAla and tRNAIle genes were revealed in the 16S-23S rDNA spacer region. Primer pair Dif1/Dir1, synthesized according to the sequence of the spacer region, could effectively amplify a 409 bp DNA fragment from the DNA template prepared from XCD, but not from any tested pathovars of X. campestris, other bacterial species or epiphytic bacteria isolated from anthurium. A minimum of 1.5 pg DNA or 3-4 XCD cells was sufficient to amplify the specific XCD PCR fragments using the primer pairs S10f-11/S10r-11 and Dif1/Dir1.

博士
國立臺灣大學
動物學研究所
90
The otoliths of the glass eels Anguilla australis, A. reinhardtii and A. dieffenbachii specimens collected from the estuaries of eastern Australian and New Zealand were examined to clarify their early life history and migrating routes from the spawning grounds to the nursing grounds. The ages of the glass eels were estimated by counting daily growth increments in otoliths. The dramatic increase in increment width and the decline of the Sr:Ca ratios in otoliths were used to determine the timing of metamorphosis from leptocephalus to glass eel stage. One to several discontinuous rings (elver check) appeared at the edge of otoltihs after the glass eels entered the estuaries from the ocean. The elver check was an indicator to distinguish the estuarine duration from oceanic duration in glass eel stage. The mean ages of leptocephali at metamorphosis of A. australis (n=183)、A. reinhardtii (n=176) and A. dieffenbachii (n=96) were 171.2±20.0d, 144.5±12.2d and 225.4±15.1d, respectively. The age from metamorphosis to estuarine arrival of A. australis, A. reinhardtii and A. dieffenbachii glass eels were 53.8±15.2d, 38.2±9.4d and 62.4±11.7d, respectively. The mean ages of A. australis, A. reinhardtii and A. dieffenbachii glass eels at estuarine arrival were 225.0±28.9d, 182.7±16.3d and 287.9±19.4d, respectively. The larval duration of glass eel was longest in A. dieffenbachii, middle in A. australis and shortest in A. reinhardtii but vice verse in growth rate. Among the 3 species, the ages at metamorphosis were linearly related with ages at estuarine arrival. This indicates that the leptocephalus metamorphosing at a younger age will arrive at the estuary as a younger glass eel. The main spwaning seasons of A. australis、A. reinhardtii and A. dieffenbachii, back-calculated from daily increments, were between December to March、June to September and October to January. The presumed spawning grounds of A. australis、A. reinhardtii and A. dieffenbachii were between Fiji and Samoa, west of Fiji and between Cook Islands and French Polynesia, respectively. Therefore, there were temporal and spatial isolation of reproduction among the 3 species. The total length and daily age of A. australis showed geographical declined from north to south, indicating that the glass eels were transported from norther to southern Australia by South Equatorial Current and East Australian Current. In addition, based on the current direction and the similarity in age of leptocephali at metamorphosis, age at catch and the time between metamorphosis and estuarine arrival, the New Zealand glass eels were unlikely to be transported across Tasman Sea from southern Australia by the East Australian Current, and they must reach their destination via different routes. Another possible migration route is transportation by the southwest flowing portion of the SEC. The differences in geographical distribution between Anguilla reinhardtii and A. australis on the eastern coast of Australia can be understood by comparing, by otolith growth increments and microchemistry, the ages between species of the eels at metamorphosis from leptocephalus to glass eels and the ages of glass eels at estuarine arrival. The shorter duration of the marine larval period and faster growth rate may make A. reinhardtii occur in tropical-subtropical waters while the longer marine larval duration and slower growth rate make A. australis dominate in more temperate waters. Consequently, the oceanic current, spawning grounds, growth rate and larval duration play an important role in determining the geographical distribution of the 3 eels. Key words, Anguilla australis, A. reinhardtii, A. dieffenbachii, otolith, early life history, migration.

博士
國立臺灣大學
動物學研究研究所
95
Population genetic structure and evolutionary scenario were investigated with the microsatellites analysis for three species of the freshwater eels, tropical Anguilla reinhardtii (Steindachner 1867), and temperate Anguilla australis (Richardson 1841) and Anguilla dieffenbachii (Gray 1842) in Australia and New Zealand. A total of 1277 glass eel specimens were used: 388 from East Australia and New Zealand for A. australis, 90 from both North and South Island of New Zealand for A. dieffenbachii, and 799 from East Australia for A. reinhardtii, including a series of monthly collections for over 12 months from the Albert River estuary. The specimens were collected from East Australis in 1997-1999 and New Zealand in 1995-1996. For A. reinhardtii there was no significant spatial and temporal differentiation in the genetic structure. This may be due to the fact that it has a short pelagic larval duration, narrow distribution range, but a long, all the year round spawning period, that facilitate the gene flow. For A. australis that has comparatively longer pelagic larval duration than that of A. reinhardtii, two geographical populations were recognized in East Australia and New Zealand, respectively. For A. dieffenbachii in New Zealand that has the longest duration of the pelagic larval stage has no population genetic differentiation due to the small land mass for dispersal. A. dieffenbachii is characterized with more ancient morphological and genetic characters than the A. australis in the same evolutionary lineage. These may suggest that temperate eel A. dieffenbachii is the earliest arrival of the freshwater eel in Oceania. Genetic variation in microsatellite loci may provide a useful tool in examining evolution and population dispersal of freshwater eels.