Evidence for two distinctive species of Pseudorchis (Orchidaceae) in Scandinavia.

Reinhammar, L.-G. 1995. Evidence for two distinct species of Pseudorchis (Orchidaceae) in Scandinavia. - Nord. J. Bot. 15: 469–481. Copenhagen. ISSN 0107–055X.
Nordic populations of Pseudorchis albida s.l. were studied for variation in morphological characters. Canonical variates analysis (CVA) arrange populations in two discrete groups, corresponding to P. albida S.S. and P. straminea , respectively. In principal component analysis (PCA) of the total material a small overlap could be seen. However, separate PCA:s on members of the two taxa from the same geographic region show perfect separation. Since the two taxa are distinct in morphology as well as in additional characters, e.g. habitat preference in the area of sympatry, they are best treated as separate species. The generic name Pseudorchis is considered to be validly published and is then preferred over the later Leucorchis . A lectotype is selected for Gymnadenia albida f. subalpina .     

Differentiation patterns in the Scutellaria albida group (Lamiaceae) in the Aegean area

An experimental investigation of the mainly white-flowered Scutellaria albida group in the Aegean area was carried out. Eight populations representing maximum morphological variation as well as geographic separation were chosen for crosses between populations. Strong sterility barriers were observed in the Cretean endemic species, S. sieberi Benth., which also deviated morphologically and is probably an ancient relic. Strong crossing barriers were also found in plants from Euboea, and, in spite of little morphological differentiation from S. albida L. s. str., they are treated as a separate species, S. goulimyi Rech. fil. Crossing barriers of intermediate strength were present in morphologically distinct material from N Sporades, which is also treated as a separate species, S. sporadum Bothmer sp. nov. All other populations showed high compatibility in crosses among themselves, viz. populations from Bulgaria, Thrace, Andros, Naxos, and Rodhos. These were treated as the same species, S. albida , having large local as well as clinal variation. Three subspecies are retained: ssp. albida in the north; ssp. perhispida (Bornm.) Bothmer in E Macedonia, Thrace and on the islands; and the mainly purple-flowered, ssp. vacillans (Rech. fil.) Bothmer, endemic to the peninsula of Athos. Evolutionary pathways and phytogeographical patterns are discussed.
S. sporadum is mainly inbreeding and, in S. sieberi , indications of a self-incompatibility system were found. The other taxa have a more versatile system.     

A new biomineral identified in the cores of teeth from the chiton <Emphasis Type="Italic"> Plaxiphora albida</Emphasis>

The hydrated iron(III) oxide limonite is reported for the first time as a biomineral. In situ laser Raman spectra of the tooth cores from major lateral teeth of the chiton Plaxiphora albida are compared with those of synthetic and mineral iron phosphates and iron oxides. Raman spectra measured on iron phosphate and iron oxide standard materials are shown to be easily distinguishable from one another. The central tooth cores of mature P. albida teeth do not show any evidence for the presence of a separate iron phosphate mineral. Rather, in each tooth a narrow band of the hydrated iron(III) oxide limonite is shown to separate the magnetite of the tooth surface from a central core region comprising both lepidocrocite and limonite. The high concentration of phosphorus in P. albida tooth cores, previously observed by energy dispersive spectroscopy, is not associated with a separate iron phosphate mineral, indicating that this element may be adsorbed onto the surface of the iron oxide minerals present. The failure to detect a separate iron(III) phosphate is discussed with reference to other chiton species that display high levels of iron and phosphorus in the cores of their mature major lateral teeth.     

Bradyrhizobium sp. Strains that nodulate the leguminous tree Acacia albida produce fucosylated and partially sulfated nod factors

We determined the structures of Nod factors produced by six different Bradyrhizobium sp. strains nodulating the legume tree Acacia albida (syn. Faidherbia albida). Compounds from all strains were found to be similar, i.e., O-carbamoylated and substituted by an often sulfated methyl fucose and different from compounds produced by Rhizobium-Mesorhizobium-Sinorhizobium strains nodulating other species of the Acaciae tribe.     

Cotyledon architecture and anatomy in the Acacieae (Leguminosae: Mimosoideae)

Cotyledon size, shape, venation pattern and anatomy have been investigated in Faidherbia albida and 152 species of Acacia representing the three subgenera Acacia, Aculeiferum and Heterophyllum. Cell volumes of epidermis, palisade and storage tissue, stomatal frequency, stomatal index and frequency of stomatal types have been determined for F. albida and 12 species from each subgenus. The data obtained support the recognition of the subgenera of Acacia as separate taxa but provide no indication of their status. The evidence from cotyledons also supports the separation of Faidherbia from Acacia , and the amalgamation of the Acacieae and Ingeae.     

Interspecific genetic divergence in sciaenids from Japan and its adjacent waters

Genetic divergence and phylogenetic relationships amongNibea mitsukurii, Nibea albiflora, Pennahia argentata, Argyrosomus japonicus, Atrobucca nibe andLarimichthys crocea were investigated by examining the electrophoretic patterns of 14 enzymes. The allele frequencies of 21 loci were estimated to calculate the genetic distances (D). The averageD value among the sciaenid species increased in proportion to the level of taxonomic category. Relationships estimated by genetic markers well accorded with those estimated by morphological characters. The 6 sciaenid species were clearly divided into two distinct groups at aD value of 1.41.     

Phylogenetic estimation of Sciaenidae in the East China Sea inferred from nuclear EPIC DNA sequence variation

Here we describe a phylogenetic analysis of sciaenids of the East China Sea based on nuclear exon-primed intron-crossing genes (EPIC markers) and a mitochondrial gene (CO1). Separate analyses of the two data partitions resulted in mostly congruent trees. Although there were some differences in the classification of these species, the main difference between trees obtained by the mitochondrial gene (CO1) and nuclear DNA sequences was the position of Miichthys miiuy and Johnius belangerii. In the mitochondrial phylogeny, Johnius belangerii was placed at the most basal position forming an individual clade, while other species formed another large cluster. Miichthys miiuy formed an independent basal sub-clade grouped with Larimichthys and Collichthys. Collichthys lucidus was grouped with Larimichthys crocea and Larimichthys polyactis. Trees based on the nuclear genes differed somewhat from those based on the CO1 mitochondrial gene. In this analysis, two groups resulted, the Larimichthys and Collichthys clade, and another clade including a total of five species: Johnius belangerii, Nibea albiflora, Pennahia argentata, Sciaenops ocellatus, and Argyrosomus japonicus; Johnius belangerii clustered with Nibea albiflora. Miichthys miiuy was placed at the basal position of the other cluster because it was an independent basal sub-clade grouped with Johnius belangerii, Nibea albiflora, Pennahia argentata, Sciaenops ocellatus, and Argyrosomus japonicus. Many aspects of the phylogeny of the Sciaenidae remain unresolved, and further analysis based on more molecular information and extensive taxon sampling is necessary to elucidate the phylogenetic relationships among the major lineages within Sciaenidae.     

Evolution of temperature responses in the Cladophora vagabunda complex and the C. albida/sericea complex (Chlorophyta)

Differentiation in temperature responses (survival and growth) was investigated among isolates of two tropical to temperate green algal lineages: the Cladophora vagabunda complex and the C. albida/sericea complex. The results were analysed in relation to published data on 18S rRNA and ITS sequence divergence, which have shown that the overall degree of genetic divergence is similar in the two lineages but that very different patterns of radiation have occurred. In the C. vagabunda complex, the two main clades in the well-resolved phylogenetic tree differed mainly in their tolerance to low temperatures. Within-clade variation was no stronger in the Atlantic/Pacific than in the all-Pacific clade. In the C. albida/sericea complex, six distinctive ITS types indicated early radiation. Although distinctive differences were found between some of these types, the thermal responses of others were very similar, indicating physiological stasis. In both lineages there was evidence for some adaptation to local temperature regimes but phylogenetic constraints were generally more important. Isolates with the same ITS sequences showed similar temperature responses even though collected from different climate zones. Evidence was found for a physiological trade-off between growth at high and at low temperatures in the C. albida/sericea complex, whereas, in the C. vagabunda complex, one clade showed more eurythermal growth responses than the other. In the C. vagabunda complex, which is the ancestral lineage of the C. albida/sericea complex, major differentiation was found in cold tolerance but not in heat tolerance, whereas the reverse pattern was found in the derived C. albida/sericea complex. These findings suggest that an acquisition of cold tolerance preceded the loss of heat tolerance during adaptation to colder climates.     

PCR-denaturing gradient gel electrophoresis profiling of inter- and intraspecies 18S rRNA gene sequence heterogeneity is an accurate and sensitive method to assess species diversity of arbuscular mycorrhizal fungi of the genus Gigaspora

Despite the importance of arbuscular mycorrhizal fungi in the majority of terrestrial ecosystems, their ecology, genetics, and evolution are poorly understood, partly due to difficulties associated with detecting and identifying species. We explored the inter- and intraspecies variations of the 18S rRNA genes of the genus Gigaspora to assess the use of this marker for the discrimination of Gigaspora isolates and of Gigasporaceae populations from environmental samples. Screening of 48 Gigaspora isolates by PCR-denaturing gradient gel electrophoresis (DGGE) revealed that the V3-V4 region of the 18S rRNA gene contained insufficient variation to discriminate between different Gigaspora species. In contrast, the patterns of 18S ribosomal DNA (rDNA) heterogeneity within the V9 region of this marker could be used for reliable identification of all recognized species within this genus. PCR-DGGE patterns provided insight into some putative misidentifications and could be used to differentiate geographic isolates of G. albida, G. gigantea, and G. margarita but not G. rosea. Two major clusters were apparent based upon PCR-DGGE ribotype patterns, one containing G. albida, G. candida, G. ramisporophora, and G. rosea and the other containing G. decipiens and G. margarita. Dissection of the DGGE patterns by cloning, DGGE screening, and sequencing confirmed these groupings and revealed that some ribotypes were shared across species boundaries. Of the 48 isolates examined, only two displayed any spore-to-spore variation, and these exceptions may be indicative of coisolation of more than one species or subspecies within these cultures. Two Brazilian agricultural soils were also analyzed with a Gigasporaceae-specific nested PCR approach, revealing a dominance of G. margarita within this family.     

高温胁迫对粉带扦插苗形态和生理特征的影响

对粉带扦插苗进行高温处理,研究高温胁迫对其外观形态和生理生化指标的影响。结果表明,35℃高温胁迫或40℃高温胁迫短时间(2d)内,扦插苗受害指数和大部分生理生化指标均与对照差异不显著,粉带未产生热伤害;40℃高温胁迫长时间(3d)或45℃高温胁迫短时间(2d)内,粉带产生较严重的热伤害,但植株仍能自我调节和恢复,受害指数、可溶性蛋白、可溶性糖、Pro、MDA含量、SOD和CAT活性均急剧上升,叶绿素、类胡萝卜素含量明显减少,POD活性略有降低;45℃高温胁迫3d,对粉带产生热伤害,各项生理生化指标急剧下降,40%的扦插苗整株萎蔫枯死,大部分植株已无法通过自身调节恢复。粉带叶片的叶绿素、Pro、MDA含量和POD活性在高温胁迫时变化明显,且4种指标与受害指数之间具有显著相关性,其相关系数绝对值均在0.88(P0.001)以上,可作为耐热性鉴定指标。     

Allozyme differentiation between lowland and alpine populations of Pseudorchis albida s.lat. (Orchidaceae) in Sweden

Two taxa are usually recognized in Scandinavian Pseudorchis albida s.1. (Orchidaceae), the lowland to subalpine P. albida s.s., and the alpine P. straminea . We used allozymes to study the genetical differentiation within and among populations and taxa. Four populations of P. albida s.s. and two populations of P. straminea , all from Sweden, were included in the study. Eighteen loci of thirteen different enzyme systems were analyzed. Five loci were variable within, or between, the taxa. The taxa had different alleles at one of the five variable loci, whereas there was overlap at four loci. In all, 22 different alleles were found. Two of these alleles were confined to P. albida s.s., while four alleles were confined to P. straminea . In P. albida s.s., one locus out of 15 (6.7 %) was polymorphic. In P. straminea , three loci out of 18 (16.7 %) were polymorphic. In both taxa, the average number of alleles per polymorphic locus was 2.0 (each polymorphic locus had two alleles). Nei's genetic identity was 0.81 between taxa, and about 1 among populations of P. albida s.s., while the identity between the two populations of P. straminea was 0.98. Although the differentiation is small, present-day distributions of taxa suggest that the divergence probably started before the Weichselian glaciation. The low within-taxon and within-population variation in Scandinavia may be due to ancient founder events. The association of P. albida s.s. with anthropogenic hay-meadows and open woodland and the association of P. straminea with open mountain habitats suggest that taxa may have immigrated into Scandinavia at different times.     

Peptide pal9a from the venom of the turrid snail Polystira albida from the Gulf of Mexico: purification, characterization, and comparison with P-conotoxin-like (framework IX) conoidean peptides

A novel peptide, pal9a, was purified from the venom duct extract of the turrid snail, Polystira albida (superfamily Conoidea, family Turridae), collected in the Gulf of Mexico. Its primary structure was determined by automated Edman degradation and confirmed by mass spectrometry. Turritoxin pal9a contains 34 amino acid residues, including 6 Cys residues arranged in the pattern C-C-C-C-C-C (framework IX, where "-" represents one or more non-Cys amino acids), which characterizes the P-conotoxins. Peptide pal9a is the first P-conotoxin-like turritoxin characterized from a member of family Turridae of the Western Atlantic. The primary structure of turritoxin pal9a, NVCDGDACPDGVCRSGCTCDFNVAQRKDTCFYPQ-nh(2) (-nh(2), amidated C-terminus; calculated monoisotopic mass, 3679.48Da; experimental monoisotopic mass, 3678.84Da), shows variable degrees of low sequence similarity with framework IX-toxins from turrid (three species of Lophiotoma, and four species of Gemmula), terebrid (Hastula hectica), and Conus species of the Indo-Pacific (C. textile, C. gloriamaris, C. amadis, and C. litteratus) and of the Western Atlantic (C. regius). During the comparison of peptide pal9a with the other framework IX-toxins known to date, we realized that, in general, these peptides are hydrophilic, acidic compounds that have not been found in the fish-hunting Conus species studied thus far; we also found support for the notion that they may belong to several distinct gene superfamilies, even those from the same species. Given the broad distribution of framework IX-toxins within superfamily Conoidea, it will be interesting to identify the still-unknown molecular targets of P-conotoxins, P-conotoxin-like turritoxins, and P-conotoxin-like augertoxins.     

Systematics of Pseudorchis albida s.l. (Orchidaceae) in Europe and North America

In Scandinavia Pseudorchis albida (Orchidaceae)usually divided into the lowland and subalpine P. albida s.s. and the more or less alpine P. straminea. There have been some uncertainties and conflicting views concerning die taxonomic treatment of diese taxa. To address this issue, herbarium specimens of P. albida s.l. were studied for variation in morphological characters. A small-scale population study approach was used, as herbarium sheets with two or three plants were used as population samples. Canonical Variates Analysis (CVA) indicated a distinction between taxa in population means, corresponding to P. albida s.s. and P. straminea , respectively. Principal Components Analysis (PCA), however, revealed an overlap between individuals of the two taxa. The PGA analysis, furthermore, revealed that the overlap was considerably larger in material from Central Europe man in material from Fennoscandia. Student t -tests on separate characters confirmed the picture, wim more characters significantly different in Fennoscandian than in Central European material. Furthermore, a Tukey-Kramer test revealed that there were small differences between regional populations of P. albida s.s. , while there were several significant differences in single characters between the Norm American regional population of P. straminea , as compared with the Central European and Fennoscandian regional populations. In Central Europe there is no clear separation between taxa, while in Fennoscandia the taxa are more clearly separated. This probably means that there is a difference in the time of establishment in the different regions. The author suggests a distinction of taxa at the subspecies level, and argues that the clear distinction seen in Fennoscandian material is due to separate immigration histories for die two subspecies into Fennoscandia after the last period of glaciation.     

Allozyme variation in 16 natural populations of Faidherbia albida (Del.) A. Chev

The objectives of this study were (1) to investigate the genetic variability; and (2) to determine the phylogenetic relationship in the leguminous tree Faidherbia albida through out its range of distribution in East, West and Southern Africa. A total of 16 populations were subjected to enzyme electrophoresis and 6 enzyme systems (Adh, Mdh, G6pdh, Idh, 6Pgdh, and alpha-Est) encoded by 12 loci were scored. A total of fifty one different alleles were detected, with an average of 2.5 alleles per locus. Forty three percent of the loci were polymorphic at a 95% criterion. The average expected heterozygosity (gene diversity index H(e)) was 0.141. All provenances showed significant deviation from Hardy-Weinberg expectation. The UPGMA cluster analysis, based on Modified Rogers distance revealed close similarities between Eastern and Southern African provenances, except Debre zeit from Ethiopia, which was closest to West African populations than to the East African populations. Also, Bignona from West Africa was peculiarly closer to East African provenances. Differentiation of West African populations from Eastern and Southern African provenances was quite evident, emphasising the clinical pattern of variation in these two major geographical races of F. albida in Africa. Wright's F-statistics showed an overall significant deficit of heterozygotes, a common feature in mixed mating, entomophilous, widespread species such as F. albida. The dendrogram analysis showed wide separation among the three Ethiopian provenances indicating a high level of genetic differentiation and diversity among them.     

Diversity and colonization of arbuscular mycorrhizal fungi in the tree fern Alsophila firma in rainy and dry season

Alsophila firma is a deciduous tree fern considered as an emblematic species of Mexican tropical montane cloud forest (TMCF). We studied spores diversity, structure and colonization by arbuscular mycorrhizal fungi (AMF) within the roots of the Alsophila firma in rainy and dry season. Eighteen species of the genera Acaulospora (5), Gigaspora (4), Glomus (4), Funneliformis (2), Sclerocystis (2) and Scutellospora (1) were identified. The species F. constrictum, F. geosporum, Gigaspora albida, G. decipiens, Glomus microaggregatum and Sclerocystis coremioides are reported for the first time in TMCF. The dominant genera were Funneliformis and Acaulospora. In rainy season, a higher richness (H′ t_0.005(2)9?=?4.78) and evenness (E) of AMF spores was recorded, compared to the dry season. However, the degree of colonization was statistically significant higher in the dry season. This study is the first to estimate the species richness of AMF associated with the rhizosphere of a fern in Mexico as well as for A. firma.     

Pollination, breeding system and seed abortion in some African acacias

TYBIRK, K., 1993. Pollination, breeding system and seed abortion in some African acacias . Studies of the flower visitors and pollination ecology of Acacia albida Del., A. nilotica (L.) Willd. ex Del. A. tortilis (Forssk.) Hayne and A. Senegal (L.) Willd. in Senegal and Kenya showed a high diversity of floral foragers. One hundred and eighteen taxa of insects mainly from Hymenoptera, Lepidoptera, Coleoptera and Diptera were collected. The most important pollen vectors were bees from the families Megachilidae and Halictidae, and wasps from the families Scoliidae and Eumenidae. Beetles, flies and butterflies were secondary pollen vectors. Diversity and frequency of flower visitors of species with floral nectar ( A. Senegal and A. albida ) were not clearly different from species without floral nectar ( A. tortilis, A. nilotica ). Acacia tortilis was almost exclusively outcrossed (Index of Self Incompatibility = 0.2), with 5.5% of the inflorescences (0.13% of the flowers) developing fruits. The number of seeds per pod was positively correlated with dispersal type. Wind dispersed species had fewer seeds per pod than animal dispersed species. About 5% of the seeds were aborted in A. tortilis and A. nilotica , while 22–48% of the seeds were aborted in A. Senegal, A. ataxacantha DC. and A. polyacantha Willd. Most abortions in the latter three species occur in the proximal end of the pods, indicating selective seed abortion.