Isozyme variation inFaidherbia albida (Leguminosae, Mimosoideae)

Genetic variation has been assessed in 30 populations (931 families) ofFaidherbia albida (Leguminosae, Mimosoideae) from across its entire African range, using six isozyme loci identified by five enzyme systems. Among the populations studied a null allele was proposed to explain the absence ofLap-1 activity in populations from southern and eastern Africa. The mean percentage of polymorphic loci per population, the mean number of alleles per locus and the mean genetic diversity within populations were 31.7%, 1.6 and 0.127 respectively. Genetic diversity was greatest in populations from West Africa and lowest in populations from eastern/southern Africa, with Ethiopian/Sudanese populations intermediate. The overall degree of genetic differentiation between populations (G_ST) indicated that approximately 56% of the enzyme variation resided within populations. Clustering of Nei's unbaised genetic distances calculated between all populations produced a dendrogram that generally followed the geographic distribution of the populations. Two major groups were identified that may be considered the eastern/southern African and the Ethiopian/West African clusters. Within the Ethiopian/West African cluster two subclusters could be recognised, one broadly corresponding to those populations from Ethiopia/Sudan and the other to those populations from West Africa. The implications of these results for theories regarding the origin ofF. albida in Africa are discussed.     

The flavonoids of theFagonia bruguieri complex (Zygophyllaceae)

Seven flavonol glycosides were identified from the main taxa of theF. bruguieri complex. Of these, kaempferol 3-rhamno-galactoside, Quercetin 3-rhamnogalactoside and Quercetin 3-galactoside are new records for the genusFagonia L. and theZygophyllaceae s. str. The distribution of these flavonoid glycosides is discussed with respect to the morphology, chemosystematics, and possible phylogeny of the complex and the genus.Dedicated to Hofrat Univ.-Prof. DrKarl Heinz Rechinger on the occasion of his 80th birthday.     

Differences in flavonoid constituents among the species ofFagonia sinaica complex (Zygophyllaceae)

Eight flavonol glycosides were detected in the three species of theFagonia sinaica complex. They were fully characterized as the 3-glucosides of kaempferol, quercetin and isorhamnetin, 3-rutinoside of quercetin and 3,7-diglucoside of quercetin and isorhamnetin. Two additional glycosides were partially characterized as a kaempferol 3,7-diglycoside and quercetin 3-diglycoside.     

Isozyme variation among teak (Tectona grandis L.f.) provenances

Fourteen enzyme systems were analysed in leaf parenchyma of nine native and introduced populations of teak. These enzyme systems were encoded by 20 putative loci of which 18 were polymorphic. Populations showed a general lack of heterozygosity (average F_IS = 0.11). On average over the 18 polymorphic loci, the genetic differentiation among provenances varied according to the estimator: 0.09 for G_ST, 0.12 for F_ST and 0.19 for . The cluster analysis showed two main gene pools, the first consisted of the Indian provenances and the second of African, Indonesian and Thai provenances. Genetic distances among populations of the same group were similar, and lower than the genetic distances between populations from different groups. The factorial analysis on genotypes of seedlings also showed the same geographic differentiation into two major groups. The possible natural distribution of teak in Java is discussed.     

Isozyme variation in Larrea ameghinoi and Larrea nitida (Zygophyllaceae): genetic diversity and its bearing on their relationship

Electrophoretic variants for 11 isozyme systems were examined by horizontal polyacrilamide gel electrophoresis in natural populations of Larrea ameghinoi and L. nitida (section Larrea). The two taxa presented fixed alternative allelic variants at loci Adh-1, Gdh-1 and Mdh-1. Genetic variability estimates showed no statistically significant differences among populations of section Larrea (H_e: 0.097–0.167). However, these values were significantly lower than those reported for species of section Bifolium (L. divaricata, diploid L. tridentata) in a previous contribution (H_e: 0.17–0.29). Positive and highly significant Wright's fixation indices are in agreement with higher amounts of inbreeding for nitida and L. ameghinoi, as suggested on the basis of floral morphology by previous authors. Moreover, the higher levels of genetic differentiation obtained for conspecific populations of section Larrea as compared to those of section Bifolium are also consistent with these observations. Nei's genetic identity values obtained for sympatric (I=0.80) and allopatric (I=0.63–0.73) L. ameghinoi – L. nitida population pairs are concordant with those expected for different, but closely related congeneric species. This revised version was published online in July 2006 with corrections to the Cover Date.     

Patterns of genetic differentiation in two annual bromegrasses,Bromus lanceolatus andB. hordeaceus (Poaceae)

Infraspecific genetic differentiation was analysed in two tetraploid annual bromegrasses,Bromus lanceolatus (from N Africa) andB. hordeaceus (from N Africa and France). Genetic analysis of populations was based on allozyme polymorphisms at 17 loci. Different fixed heterozygous phenotypes were scored in both species, according to their allopolyploid origin. In N Africa, more variation occurred among populations ofB. lanceolatus than ofB. hordeaceus. The variation was not randomly distributed among populations of both species. InB. lanceolatus, differentiation was correlated with climatic variables rather than with geographic distance between populations. Higher correlation of genetic differentiation with geographic distance occurred inB. hordeaceus, particularly at large geographic scale, between French and N African populations. Within each region, the populations appeared weakly genetically differentiated, even when belonging to different subspecies.     

Studies on theStellaria longipes complex (Caryophyllaceae): Isozyme variability and the relationship betweenStellaria longipes andS. longifolia

Genetic variation within and the relationship betweenStellaria longipes Goldie andS. longifolia Muhl. were studied. Ten enzyme systems were assessed in eight natural populations ofS. longipes (25 loci) and three ofS. longifolia (20 loci) using starch and polyacrylamide gel electrophoresis. Patterns of population differentiation corresponded to geographic distance. There was no evidence that polyploidS. longipes had greater electrophoretic variability than diploidS. longipes. The isozyme data confirmed extensive population differentiation in these species and, within that context, a relatively close relationship betweenS. longipes andS. longifolia. It was postulated that diploids of these two species might be the progenitors of tetraploidS. longipes.     

Isozyme variation and alleged progenitor-derivative relationships in theMedicago murex complex (Fabaceae)

Chromosomal studies ofMedicago lesinsii (n = 8) and its close relativeM. murex (n = 7) have led to the competing hypotheses that the latter is derived directly from the former, or that both originated from a common ancestor. In contrast to the relatively variableM. murex, M. lesinsii proved to be almost uniform isozymically, except that most populations of Greece differed by one allele from plants of the remainder of the range. This Greek variant ofM. lesinsii was indistinguishable from one of the isozyme variants ofM. murex. The greater level of allozyme variation inM. murex was consistent with its greater ecological amplitude and competitive ability. Also, this suggests thatM. murex is unlikely to have originated directly from the less variableM. lesinsii. The data suggest that either both species originated from a common ancestor, or that the n = 8 species evolved from the n = 7 species, a mode of chromosome evolution not previously hypothesized for the genus.     

Isozyme evidence of relationships withinSphagnum sect.Acutifolia (Sphagnaceae,Bryophyta)

Ten enzyme systems coding for 13 putative loci were studied in 12 European species ofSphagnum sect.Acutifolia (peat mosses). On average seven plants from each of 73 collections made throughout N Europe were analysed. Despite complex morphological variation, all species expressed unique allele combinations. Principal components and cluster analyses based on allele frequencies showed that sect.Acutifolia can be divided into two major groups; one comprisingSphagnum fimbriatum, S. girgensohnii andS. molle; the second comprisingS. capillifolium, S. angermanicum, S. fuscum, S. quinquefarium, S. rubellum, S. subfulvum, S. subnitens andS. warnstorfii. These groups are linked byS. russowii, which is shown to be an allopolyploid, with fixed heterozygosity at 6 to 8 of the loci. The presumed progenitors ofS. russowii areS. girgensohnii andS. rubellum. Allelic data also indicate thatS. teres from sect.Squarrosa is related toS. girgensohnii andS. fimbriatum. The bisexual species tend to be less variable than the unisexual species.     

Isozyme diversity in sour,sweet, and ground cherry

Thirty-six sour (Prunus cerasus L.), sweet (P. avium L.), and ground cherry (P. fruticosa Pall.) selections were evaluated for seven enzyme systems and principal coordinate analysis was used to examine isozyme divergence among these cherry species. The enzyme systems studied were phosphoglucose isomerase (PGI), isocitrate dehydrogenase (IDH), phosphoglucomutase (PGM), 6-phosphogluconate dehydrogenase (6-PGD), leucine aminopeptidase (LAP), shikimate dehydrogenase (SKDH), and malate dehydrogenase (MDH). The first principal coordinate, which accounted for 41% of the total variation, separated the diploid sweet cherry selections from the sour, ground, and sour x ground cherry tetraploids. An additional 86 selections were evaluated for up to six of the enzyme systems to determine the polymorphisms at the enzyme loci and the level of heterozygosity between the diploid sweet cherry and the tetraploid species and interspecific hybrids. 6-PGD was the most polymorphic enzyme exhibiting 16 patterns. The tetraploid cherry species were more heterozygous than the diploid sweet cherry with an average heterozygosity of 78% compared to 19% for the diploids.     

Isozyme evidence and the origin ofSenecio vulgaris (Compositae)

An electrophoretic survey of isozyme variation was conducted to test the hypothesis thatSenecio vulgaris L. (2n = 40) is of autotetraploid origin fromS. vernalis Waldst. & Kit. (2n = 20). It was established thatS. vulgaris exhibited fixed heterozygosity at three loci examined, showed disomic inheritance at all polymorphic loci, and contained a gene (Est-1) and an allele (Aat-3b) which were not present in the single population ofS. vernalis surveyed. From this it is concluded thatS. vulgaris is not of autotetraploid origin. Instead, the genetic evidence is in keeping with an allopolyploid origin ofS. vulgaris with the possibility thatS. vernalis acted as one of its two parents.     

Isozyme variation in some populations of wild diploid wheats in Iran

Isozyme electrophoresis data of seed extracts from 11 populations of diploid wheat species (Triticum boeoticum Bioss. and Triticum urartu Thumanian ex Gandilyan), distributed mainly in the western and west-northern Iran, were investigated. The five enzyme systems used were peroxidase, polyphenol oxidase, superoxide dismutase, malate dehydrogenase and catalase. The first three were found to be useful as molecular marker for characterization of diploid wheat populations. A total of 13 bands from three enzyme systems were recorded. The value of a ‘Jaccard's’ similarity coefficient ranges from 0.333 to 1.000. Data analysis was done using clustering method UPGMA. On the basis of Jaccard's coefficient, the obtained dendrogram supports previous relationship between T. boeoticum and T. urartu as separate species as well as reflecting their distinct gene pools and substantiating their specific recognition despite the overall morphological similarity.     

Rapid colonization of Belgian breakwaters by the direct developer,Littorina saxatilis (Olivi) (Prosobranchia,Mollusca)

The Belgian coast has no natural rocky sites but a number of man-made constructions are colonized by rocky shore organisms. The rough periwinkle, Littorina saxatilis (Olivi), lacks a planktonic larval stage but is found on most breakwaters along the Belgian coast, a few built as recently as 1986. This indicates a good potential of dispersal along this sandy shallow coast, nearly as good as for the planktonic developer Littorina littorea (L.) which is found on generally the same sites in Belgium. The breakwater populations of L. saxatilis, however, tend to be somewhat less variable (level of heterozygosity about 10% less) than non-Belgian L. saxatilis populations of natural sites. This suggests that the breakwater populations have passed through bottlenecks when founded, but probably restored population sizes fairly rapidly afterwards. No relationship is found between geographic and genetic distances between populations of L. saxatilis.     

Isozyme variation and correspondence with unusual infrared reflectance patterns inPhragmites australis (Poaceae)

Isozyme variation was investigated in populations ofPhragmites australis (Poaceae) which have recently invaded and taken over marsh habitat of the Mississippi River delta. Infrared aerial photographs in the Garden Island Bay subdelta of the extensiveP. australis populations reveal distinct, clone-like circular patches within a predominant background. Preliminary evidence indicates that the infrared color differences represent distinct morphological types. However, there are no obvious environmental factors that could account for the peculiar patterns.P. australis collections were taken from five separate and distinct patches and adjacent background. Only two electrophoretic phenotypes were found: one from patches and one from the background. In comparing the two, 20% of the 40 loci scored are fixed for alternate alleles. These results indicate a clear correspondence of infrared reflectance with electrophoretic phenotype. In addition, the genetic uniformity as evidenced by the discovery of only two electrophoretic phenotypes supports the contention that the recent spread ofP. australis throughout the Mississippi River delta has been primarily, if not exclusively, a result of vegetative propagation.     

五条河流青海湖裸鲤的同工酶变异

为全面了解青海湖裸鲤遗传多样性现状,采用水平淀粉凝胶电泳技术分析了青海湖裸鲤[样品采自青海湖的五条支流,分别为泉吉河(QJ)、沙柳河(SL)、哈尔盖河(HEG)、布哈河(BH)以及甘子河(GZ)]的13种同工酶,共记录26个位点,统计了基因频率,计算了其遗传多样性。结果表明:26个基因位点中多态位点6个,分别为Pgm、Hk、Cat、Gdh、Es-t1、S-Mdh,多态位点比例(P0.99)为23.08%,表明青海湖裸鲤的五个群体皆具有较高的遗传多样性水平;分别计算了五个群体的平均杂合度(H)为0.1161(HEG)、0.1178(GZ)、0.1304(SL)、0.1305(BH)、0.1287(QJ),多态位点比例(Ae)分别为1.3112(BH)、1.3069(SL)、1.2542(GZ)、1.2492(HEG)、1.2453(QJ);除泉吉河群体外,其它四个群体的遗传偏离指数均为负数,表明多数群体处于一定程度的杂合子缺失状态;计算了五个群体间的遗传距离以及遗传相似度,结果显示群体间遗传距离与遗传相似度与各个河流的地理位置具有很强的相关性;根据五个群体的遗传距离进行了聚类分析,通过构建系统树图将其基本分为两大种群,甘子河与哈尔盖河两群体为一类群,另外三个群体分为一个类群;计算群体间的基因流(Nm)为7.2013,说明河道之间具有较为广泛的基因交流,并计算了两两群体间的基因流,其中布哈河群体与其它群体间的基因交流都较为广泛。     

Allozyme variation within and between populations inLolium (Poaceae)

Isozyme analysis was used to determine genetic variation within and between populations of sevenLolium species. All populations from the inbreeding species (L. temulentum, L. remotum, L. loliaceum, andL. persicum) were completely fixed for all enzymes scored. They also contained, for four of the five enzyme systems studied, exactly the same allelic variant. The three cross-breeding species showed large within-population variation and much less between-population variation. The great similarity of the allozymic variants found in all species, made the division of the genusLolium into species on basis of allozymic data difficult. It was not possible to separate the different inbreeding species from each other. Within the cross-breeding groupL. multiflorum andL. rigidum could be distinguished fromL. perenne. L. multiflorum, andL. rigidum could, with more difficulty, also be separated from each other. Allelic variation could have more relation with the provenance of the populations than with taxonomic classification.Genetic variation inLolium spp. II. For first part see Pl. Syst. Evol. 188: 87–99.     

Allozyme variation in the diploid (A genome) populations ofScilla scilloides (Hyacinthaceae)

Allozyme variation at eleven loci encoding seven enzyme systems were examined in 20 populations of diploid (genome AA, 2n = 16)Scilla scilloides in China. In comparison with the average species of seed plants studied, populations of this species display a high amount of genetic variation (A = 2.0, P = 58.6%, H_o = 0.172, and H_e = 0.185). Allozyme variation pattern revealed predominant outcrossing within populations and considerable differentiation (F_ST = 0.314) among populations as well as between the subtropic and temperate regions. The wide distribution, long existence and outcrossing are presumably the main factors responsible for the high genetic diversity within populations. But the gravity dispersal of seeds and pollination by small insects set limits to the increase of genetic variation within populations and promote differentiation between populations and regions. In addition, allozyme variation does not distinguishS. scilloides var.albo-viridis and suggests that subtropic populations may be considered as a genetic entity.     

Morphological variation among members of theStellaria longipes complex:S. longipes,S. longifolia,andS. porsildii (Caryophyllaceae)

Morphological relationships were investigated among diploidStellaria porsildii, polyploidS. longipes, and diploidS. longifolia. Canonical discriminant analysis, based on a priori assumptions to maximize differences among groups, showed thatS. longipes clusters equally distant between the two diploid species along an axis connecting the diploids' centroids, but it differs along an axis perpendicular to this axis. The intermediacy along the former axis is evidence thatS. longipes is an amphiploid derived fromS. longifolia andS. porsildii. The divergence along the latter axis may be attributable to adaptively valuable heterotic traits which were retained following amphidiploidization. The only morphological discontinuity occurred between the two diploids, whereas the morphological range ofS. longipes overlapped the range of both diploids forming a continuum. The lack of discrete clusters is likely due to hybridization and introgression withS. longifolia on one hand, and convergence of traits betweenS. longipes var.monantha andS. porsildii on the other. High a posteriori assignments in classificatory discriminant analysis supports the separation ofS. longipes var.monantha from otherS. longipes specimens. AlthoughS. longipes var.monantha grouped close toS. porsildii, the two groups separate based on leaf shape traits. Overall results support, firstly, the hypothesis thatS. porsildii is a diploid parent species which by hybridizing withS. longifolia gave rise to polyploidS. longipes. Secondly, results suggest thatS. longipes var.monantha converged morphologically towardsS. porsildii relatively recently due to ecological specialization, and merits distinction at least as a variety ofS. longipes.     

Regeneration of transgenic vegetable brassicas (Brassica oleracea andB. campestris) via Ri-mediated transformation

A procedure for the production of fertile transgenic brassicas via Ri-mediated transformation is reported in this paper. Transgenic hairy root lines were selected for 12 vegetable brassica cultivars and lines representing six varieties: broccoli, Brussels sprouts, cabbage, cauliflower, rapid-cycling (allBrassica oleracea) and Chinese cabbage (B. campestris). Leaf explants or petioles of intact cotyledons were co-cultivated withAgrobacterium strain A4T harbouring various binary vectors. The T-DNA region of all binary vectors contained a neomycin phosphotransferase II gene for kanamycin resistance, in addition to other genes. Hairy root lines grew prolifically on hormone-free medium containing kanamycin. Transgenic shoots were regenerated from all cultivars either spontaneously or after transfer of hairy roots to a hormone-containing medium. Southern analysis confirmed that the plants were transgenic. Plants from all brassica types were successfully transferred to greenhouse conditions. Plants were fertile and segregation analysis confirmed transmission of traits to progeny.Abbreviations BA 6-Benzylaminopurine - GUS -Glucuronidase - LS Linsmaier and Skoog medium - NAA I-Naphthaleneacetic acid - NPTII Neomycin phosphotransferase II - TDZ thidiazuron