INTERFERENCE THROUGH IMPROPER POLLEN TRANSFER IN MIXED STANDS OF IMPATIENS CAPENSIS AND I. PALLIDA (BALSAMINACEAE)

Mechanisms of interference through improper pollen transfer are described for sympatric populations of the simultaneously flowering annuals Impatiens capensis and I. pallida. Stigmas of both Impatiens species are receptive to conspecific pollen from the time of androecium disarticulation until after perianth drop. Pollen of I. pallida adheres to, and germinates on, the stigmas of I. capensis. The pollen tubes reach the ovules but do not fertilize them. In contrast, pollen of I. capensis adheres poorly to I. pallida stigmas and fails to germinate. Pollen mixtures of the two Impatiens species cause a much greater reduction in fruit set in I. capensis than in I. pallida. Despite the interference of I. pallida pollen, I. capensis persists in mixed populations with I. pallida by: 1) possessing stigmas receptive to pollen throughout the female phase; 2) having the ability to produce a full seed complement via one pollination event; and 3) possessing cleistogamous flowers to ensure sexual reproduction.     

Cloning and sequencing of cDNA encoding glutamine synthetase from the sea anemone Aiptasia pallida

Glutamine synthetase (GS) catalyzes the addition of ammonium to glutamic acid to form glutamine and plays a crucial role in the nitrogen assimilation of the sea anemone Aiptasia pallida and its endosymbiotic algae. We describe the cDNA cloning and sequence analysis of GS mRNA from A. pallida based on polymerase chain reaction (PCR) technology that employed a combination of degenerate and A. pallida-specific primers. The sequenced cDNA approximates 1620 nucleotides and is characterized by an open reading frame of 1107 nucleotides that encodes a protein of 369 amino acid residues. Comparisons of the deduced sea anemone GS protein to a wide range of species demonstrated greatest amino acid sequence identity to sea urchin GS (66%) and least identity to green algae GS (51%). The sequenced cDNA can be used in future research to study GS gene expression in A. pallida.     

ENHANCEMENT OF INBREEDING DEPRESSION BY DOMINANCE AND SUPPRESSION IN IMPATIENS CAPENSIS

We investigated the effect of intraspecific competition on the magnitude of inbreeding depression in Impatiens capensis by planting seeds from chasmogamous (CH) and cleistogamous (CL) flowers in three experimental greenhouse treatments: in individual pots, in flats in dense pure stands according to seed type, and in flats with the two seed types intermixed in a checkerboard array. The size distributions of plants grown in flats were significantly more hierarchical than those of plants grown individually, indicating that larger plants competitively suppressed smaller plants in the high-density treatments. The magnitude of inbreeding depression at high density depended upon the planting arrangement of CL and CH seeds. CH advantage was greatest when CH and CL seedlings were grown in competition with one another, suggesting that fitness differences between outcrossed and inbred individuals were intensified by dominance and suppression. For plants grown individually, the effects of maternal parent, seed weight, and emergence date on seedling size disappeared with plant age, whereas at high density these effects remained at the final harvest. Thus, plant density may influence patterns of natural selection both on mating system and on juvenile traits in natural Impatiens populations.     

A TEST OF THE SIB-COMPETITION HYPOTHESIS FOR OUTCROSSING ADVANTAGE IN IMPATIENS CAPENSIS

One of the potential selective mechanisms invoked in discussions of breeding-system evolution is that competition within sibships increases the fitness of outcrossed progeny relative to selfed progeny. We tested this sib-competition hypothesis using cleistogamous (CL) and chasmogamous (CH) seeds of Impatiens capensis in a large greenhouse experiment. The experimental design was a double replacement series which also allowed us to test for inbreeding depression and overall resource partitioning among sibships. We found no evidence for strong inbreeding depression in the study population; although plants from CH seeds had a slight advantage over plants from CL seeds in total flower and pod production, CL plants had slightly higher growth. We also could not detect significant resource partitioning among sibships nor any evidence to support the sib-competition hypothesis for outcrossing advantage. CH sibships were not significantly more variable than CL sibships in any of the phenotypic traits measured. These results suggest that sibling competition may have little importance in the evolution of Impatiens breeding systems.     

II gruppo Aristolochia pallida nell'Italia nordorientale

Abstract

The Aristolochia pallida group in the north-eastern Italy. The Aristolochia pallida group includes two closely related species: A. pallida Willd. and A. lutea Desf. For each species, a biometrical-morphological analysis on selected characters and critical notes are given. The distribution of both species in the north-eastern Italy is also defined.     

Phylogenetic Analysis of Evolutionary Relationships of the Planctomycete Division of the Domain Bacteria Based on Amino Acid Sequences of Elongation Factor Tu

Sequences from the tuf gene coding for the elongation factor EF-Tu were amplified and sequenced from the genomic DNA of Pirellula marina and Isosphaera pallida, two species of bacteria within the order Planctomycetales. A near-complete (1140-bp) sequence was obtained from Pi. marina and a partial (759-bp) sequence was obtained for I. pallida. Alignment of the deduced Pi. marina EF-Tu amino acid sequence against reference sequences demonstrated the presence of a unique 11-amino acid sequence motif not present in any other division of the domain Bacteria. Pi. marina shared the highest percentage amino acid sequence identity with I. pallida but showed only a low percentage identity with other members of the domain Bacteria. This is consistent with the concept of the planctomycetes as a unique division of the Bacteria. Neither primary sequence comparison of EF-Tu nor phylogenetic analysis supports any close relationship between planctomycetes and the chlamydiae, which has previously been postulated on the basis of 16S rRNA. Phylogenetic analysis of aligned EF-Tu amino acid sequences performed using distance, maximum-parsimony, and maximum-likelihood approaches yielded contradictory results with respect to the position of planctomycetes relative to other bacteria. It is hypothesized that long-branch attraction effects due to unequal evolutionary rates and mutational saturation effects may account for some of the contradictions. Received: 21 August 2000 / Accepted: 8 January 2001     

THE RELATIVE COSTS OF SELF- AND CROSS-FERTILIZED SEEDS IN IMPATIENS CAPENSIS (BALSAMINACEAE)

By using a generally applicable technique that involves monitoring the development and survivorship of flowers and seed capsules, I estimated the material and energetic costs of producing self- and cross-fertilized seeds in Impatiens capensis. All flowers and fruits on six plants were censused intensively for the two-month period of reproduction. Cleistogamous (selfing) flowers ripened seed in about 24 days, compared to about 36 days for the chasmogamous (outcrossing) flowers. In terms of dry weight, selfed seeds cost about two-thirds as much as outcrossed seeds: 12.4 versus 18.4 mg dry weight per seed. When adjusted to the currency of calories, and including an independent estimate of pollen and nectar production in outcrossing flowers, I estimate the costs to be about 65 and 135 calories per selfed or outcrossed seed. Sources of error include the accuracy of the estimates of flower and fruit weight, and possible differences among the developmental stages in respiratory costs. The cost discrepancy implies that outcrossed seeds should possess a countervailing fitness advantage large enough to offset their greater energetic cost.     

四川雅安地区13种凤仙花属植物花粉形态及其分类学意义

采用扫描电镜观察了中国四川雅安地区13种凤仙花属植物的花粉形态,并对其花粉形态进行了主成分分析和聚类分析,基于孢粉学和SRAP聚类结果的比较,讨论不同孢粉学特征对分类结果的影响。结果显示:(1)雅安地区13种凤仙花属植物花粉粒均为中等大小,花粉粒形状从超扁到扁球形变化,花粉粒极面观形状从矩形和椭圆形到四边形、圆形、三角型变化,且只有湖北凤仙、峨眉凤仙和匙叶凤仙是三沟花粉粒,其余种均为四沟花粉粒;外壁纹饰仅扭萼凤仙和齿萼凤仙为细小网状,其余均为网状纹饰。(2)依据不同指标进行的孢粉学聚类均将13种凤仙花属植物划分为3个类群,而SRAP聚类结果则将13种凤仙花属植物划分为5个类群;不同孢粉学聚类结果的相似率只有30.77%。(3)孢粉学聚类并未与分子聚类显示严格的对应关系,以花粉大小和形状、外壁纹饰为指标进行的孢粉学分类与SRAP分类的相似率最高(69.23%)。研究认为,选择不同的花粉形态特征作指标对分类的准确性影响较大,花粉大小和形状、外壁纹饰这2个指标对凤仙花属植物分类具有意义,而萌发沟的特征则很难作为分类的依据,花粉形态特征在分类上有局限性;进行该属植物孢粉学分类需要选择有价值的分类指标,并结合形态学、分子生物学等综合研究。     

Molecular evidence of conspecificity of South African hares conventionally considered Lepus capensis L., 1758

Conventionally, Lepus capensis is considered to range across large parts of Africa, the Middle East, Central and Far East Asia. However, a recent morphological study restricts cape hares tentatively to a small range in the Western Cape Region of South Africa and groups all other L. capensis-type hares from South Africa into a new species: L. centralis. Here, we studied molecular relationships among L. capensis-type hares from South Africa. Phenotypically and morphologically the individuals matched either the newly described L. capensis or L. centralis. We examined 66 hares for allelic variation at 13 microsatellite loci and for sequence variation of the hypervariable domain 1 of the mitochondrial control region. All tree-generating analyses of the currently obtained sequences and all South African cape hare sequences downloaded from GenBank revealed monophyly when compared to sequences of various other Lepus species. A network analysis indicated close evolutionary relationships between hares of the “L. capensis-phenotype” and the “L. centralis-phenotype” (according to Palacios et al. 2008) from the southwest of the Western Cape, relative to their pronounced evolutionary divergence from all other more central, northern, and north-eastern L. capensis-type hares. F-statistics, a Bayesian admixture STRUCTURE model, as well as a principal coordinate analysis of microsatellite data indicated close genetic relationships among all South African L. capensis-type hares studied presently. A coalescence model-based migration analysis for microsatellite alleles indicated gene flow between most of the considered subspecies of cape hare, including L. capensis capensis and L. capensis centralis, theoretically sufficient to balance stochastic drift effects. Concordantly, AMOVA models revealed only little effects of partitioning microsatellite variation into the two suggested morpho-species “L. capensis” and “L. centralis”. Under an “Interbreeding Species Concept” (e.g. a strict or relaxed Biological Species Concept), the current molecular data demonstrate conspecificity of the two proposed morpho-species “L. capensis” and “L. centralis”. Based on the present molecular data the differentiation of subspecies of cape hares from southern Africa is discussed.     

Hormonal effects on fatty acid binding and physical properties of rat liver plasma membranes

Summary The fluorescent fatty acids,trans-parimaric andcis-parinaric acid, were used as analogs of saturated and unsaturated fatty acids in order to evaluate binding of fatty acids to liver plasma membranes isolated from normal fed rats. Insulin (10^–8 to 10^–6 m) decreasedtrans-parinaric acid binding 7 to 26% whilecis-parinaric acid binding was unaffected. Glucagon (10^–6 m) increasedtrans-parinaric acid binding 44%. The fluorescence polarization oftrans-parinarate,cis-parinarate and 1,6-diphenyl-1,3,5-hexatriene was used to investigate effects of triiodothyronine, insulin and glucagon on the structure of liver plasma membranes from normal fed rats or from rats treated with triiodothyronine or propylthiouracil. The fluorescence polarization oftrans-parinarate,cis-parinarate, and 1,6-diphenyl-1,3,5-hexatriene was 0.300±0.004, 0.251±0.003, and 0.302±0.003, respectively, in liver plasma membranes from control rats and 0.316±0.003, 0.276±0.003 and 0.316±0.003, respectively, in liver plasma membranes from hyperthyroid rats (p<0.025,n=5). Propylthiouracil treatment did not significantly alter the fluorescence polarization of these probe molecules in the liver plasma membranes. Thus, liver plasma membranes from hyperthyroid animals appear to be more rigid than those of control animals. The effects of triiodothyronine, insulin and glucagon addedin vitro to isolated liver plasma membrane preparations were also evaluated as follows: insulin (10^–10 m) and triiodothyronine (10^–10 m) increased fluorescence polarization oftrans-parinaric acid,cis-parinaric acid and 1,6-diphenyl-1,3,5-hexatriene in liver plasma membranes while glucagon (10^–10 m) had no effects. These hormonal effects on probe fluorescence polarization in liver plasma membranes were abolished by pretreatment of the rats for 7 days with triiodothyronine. Administration of triiodothyronine (10^–10 m)in vitro increased the fluorescence polarization of trans-parinaric acid in liver plasma membranes from propylthiouracil-treated rats. Thus, hyperthyroidism appeared to abolish thein vitro increase in polarization of probe molecules in the liver plasma membranes. Temperature dependencies in Arrhenius plots of absorption-corrected fluorescence and fluorescence polarization oftrans-parinaric acid,cis-parinaric acid and 1,6-diphenyl-1,3,5-hexatriene were noted near 25°C in liver plasma membranes from triiodothyronine-treated rats and near 18°C in liver plasma membranes from propylthiouracil-treated rats. In summary, hormones such as triiodothyronine, insulin and glucagon may at least in part exert their biological effects on metabolism by altering the structure of the liver plasma membranes.     

Taxonomic and morphological survey of the Lygephila lusoria (Linnaeus, 1758) species-group with description of a new species (Lepidoptera,Erebidae, Toxocampinae)

The taxa of the Lygephila lusoria (Linnaeus, 1758) species-group are revised. The genital features of all known taxa are described and illustrated with special reference to the structure of vesica. The male genitalia of L. pallida pallida (Bang-Haas, 1907) are described and illustrated for the first time. L. pallida subpicata (Wiltshire, 1971) is treated here as a species, L. pallida subpicata (Wiltshire, 1971), stat. n., distinct from L. pallida. A new species, L. minima, sp. n.,from South Russia is described. Illustrations of the holotype and its genitalia are provided; a diagnostic comparison with L. pallida is given. L. alaica Remm, 1983 is included in the L. lusoria species-group for the first time.     

Traits of fatty acid accumulation in dimorphic seeds of the euhalophyte Suaeda salsa in saline conditions

The mechanism on of how salinity affects seed fatty acids accumulation remains unclear in halophytes. The present results revealed that the content of total unsaturated fatty acids in black seeds was higher than in brown seeds in the euhalophyte Suaeda salsa under controlled saline conditions. Salinity (200?mM NaCl) significantly increased the total oil content, unsaturated acid/saturated acid ratio, and content of α-linolenic acid (C18:3) (ALA), especially in brown seeds. The most abundant fatty acid in dimorphic seeds is linoleic acid (C18:2) (>70%). It appears that more ALA accumulated in brown seeds compared to black seeds. The enzyme activity of omega-3 fatty acid desaturase (ω-3 FAD) in brown seeds was much higher than that in black seeds, but salinity had no significant effect on the activity of ω-3 FAD in both brown and black seeds. The relative expression of SsFAD7 was increased by salinity, and the value in brown seeds was much higher than that in black seeds. This means salinity can, salinity can improve the quantity of fatty acids in dimorphic seeds of S. salsa, and the enzyme of ω-3 FAD and SsFAD7 may involve in the accumulation of ALA in dimorphic seeds under salinity.     

Impatiens maculifera sp. nov. (Balsaminaceae) Yunnan,China

Impatiens (Balsaminaceae) is a notoriously difficult genus to study for reasons that include small, remote and endemic areas of occurrence, and difficulty in obtaining well‐dried herbarium specimens and separating and reconstructing floral parts from available dried specimens. Impatiens has also been notoriously difficult when it comes to phylogenetic resolution at the infrageneric level, but a new system with two subgenera (Impatiens and Clavicarpa) was recently proposed by Yu et al. and it has made it easier to classify newly discovered species. Impatiens maculifera, a new species of Balsaminaceae from Malipo County, Yunnan, China described here, is similar to I. parvisepala S.X. Yu & Y.T. Hou in having racemose inflorescences, four lateral sepals, clavate capsules and ellipsoid seeds, but differs in having leaves narrowly oval or with elliptic–lanceolate blades (versus obovate or obovate–lanceolate), obvious petioles (versus leaves subsessile), racemose inflorescence with 8–12 flowers (versus 6–8 flowers), flowers greenish yellow (versus yellow), lateral united petals and lower sepal with dense red spots (versus red spots absent), and dorsal petal with apparent stalk at base (versus unapparent stalk). Morphological characters and molecular phylogenetic analyses of DNA sequences from both nuclear ribosomal and plastid genes show that the new species differs distinctively from I. parvisepala. Furthermore, I. maculifera is distinguished from other Impatiens species based on morphological, micromorphological and palynological evidence, and molecular data.     

Observations on the control of potato cyst-nematodes, Globodera rostochiensis and G. pallida in 35 English potato soils in pots by oxamyl and resistant potatoes

The increase of 35 English field populations of potato cyst-nematodes (Globodera rostochiensis and/or G. pallida) was measured on Désirée, Maris Piper, Caxton (A25/11), Cromwell (A27/20) and clone 11233 ab 22 in pots of sandy, silty or peaty loam soil. Désirée was susceptible to all populations tested and, as in field soils, the final population (Pf) was inversely related to the initial population of potato cyst-nematode eggs (Pi) in the soil. Maris Piper and Cromwell were resistant to all G. rostochiensis populations, with one possible exception. Maris Piper was susceptible to all G. pallida populations. Caxton was susceptible to some and fairly resistant to other populations of G. rostochiensis, indicating the existence either of two biotypes within the one pathotype (Rol) as yet encountered in Britain, or the existence of an additional pathotype. Caxton and Cromwell were fairly resistant to G. pallida. Clone 11233 ab 22 was only moderately resistant to both species. Resistance to potato cyst-nematode increase varied considerably, especially in Caxton (to G. rostochiensis) and in 11233 ab 22 (to both species). Oxamyl greatly reduced the increase of G. rostochiensis populations on Désirée potatoes, with the notable exception of one population but it generally had much less effect on G. pallida populations, regardless of soil type. The difference in effect on the two species may be due to a longer period of hatching in G. pallida than in G. rostochiensis and also perhaps to a second generation in G. pallida.     

FIELD GERMINATION AND SEEDLING GROWTH OF CH AND CL PROGENY OF IMPATIENS CAPENSIS (BALSAMINACEAE)

The germination behavior and early growth of chasmogamous (CH) and cleistogamous (CL) progeny of Impatiens capensis were investigated in two eastern Nebraska stands. Field germination of families of buried seeds was scored in mid-April. In one stand a significantly higher proportion of CL seeds germinated than CH seeds while no significant differences were observed in the second stand. Among-family variation in germination rates was significant in both stands. The time course of field germination was similar for CL and CH seeds. A sample of the germinated CL and CH seedlings, matched in size, was planted individually in pots and grown in the greenhouse for five wk. Early growth of CL and CH seedlings was similar. In addition, CL seedlings were as variable as CH seedlings for four morphological traits. Overall, a large fitness advantage for CH progeny was not detected in the germination and early growth of Impatiens capensis seedlings.     

Impatiens shimianensis sp. nov. (Balsaminaceae) from Sichuan,China

Impatiens shimianensis Q. Luo (Balsaminaceae), a new species from Shimian county in southwestern Sichuan province, China, is reported and its morphological characteristics are described and illustrated. Pollen grain morphology and seeds under SEM are also described. The new species is somewhat similar to I. bahanensis, I. brachycentra, I. laxiflora, I. parviflora and I. racemosa, but differs mainly by having leaf blades with white short stiff adpressed hairs; basal lobes of lateral united petals triangular, distal lobes lanceolate; and lower sepal salver‐shaped. The distinguishing characters for these six Impatiens species are given in a table.     

Selection for virulence in the potato cyst-nematode, Globodera pallida

The ability of six populations of Globodera pallida to multiply on Solanum vernei hybrids (Morag, 12380 2, Glenna and Santé) and S. tuberosum andigena hybrids (A 27/23, Paladin (ZB 35/29) and ZC 83/6) was studied in microplots and pots. Evidence was obtained of selection for virulence in one population after one year's cultivation of cvs Glenna or Morag. Similarly, after four years' continuous cultivation of cvs Morag or ZC 83/6 in microplots, three of five populations of G. pallida contained more virulent nematodes than the same populations maintained for the same period on cv. Pentland Crown (susceptible to G. pallida). These results are discussed in relation to earlier work and the use of partially resistant cultivars in the integrated control of G. pallida.     

Between an ocean and a high place: coastal drainage isolation generates endemic cryptic species in the Cape kurper Sandelia capensis (Anabantiformes: Anabantidae), Cape Region,South Africa

This study investigated the range-wide phylogenetics and biogeography of the Cape kurper Sandelia capensis, a primary freshwater fish endemic to and widespread within the Cape Floristic Region (CFR) of South Africa. Maximum likelihood, Bayesian phylogenetic and haplotype network analyses, based on two mitochondrial and two nuclear genes, revealed the existence of three reciprocally monophyletic, deeply divergent and allopatric clades that probably represent cryptic species. The West Coast Clade is largely confined to the Langvlei, Verlorenvlei, Berg and Diep Rivers, the Klein River Clade is endemic to the Klein River and the South Coast Clade is found everywhere else in the range of S. capensis sensu lato. It was hypothesised that divergences within S. capensis sensu lato probably occurred because of isolation of coastal drainages by persistent drainage divides or vicariance of current tributaries by the drowning of their confluences by high sea levels. The current distribution of lineages could be due to historical range expansion and gene flow via river capture or some other mode of transdivide dispersal or dispersal during periods of low sea level via palaeoriver confluences of currently isolated coastal rivers. Comparison of BEAST2 estimated divergence times with the timing of climatic, geological and geomorphological events supported long-term coastal drainage isolation, punctuated by rare transdivide dispersal events and limited palaeoriver dispersal, as the best explanation of current phylogeographic and divergence patterns in S. capensis. Hydrological barriers that block upstream passage in palaeotributaries could hypothetically explain why S. capensis failed to disperse through certain palaeoriver confluences. There were several sites where biogeographic patterns have likely been confounded by human translocation of S. capensis. Alien fish predators and water extraction may threaten the three cryptic species more severely than previously realised, due to their smaller population sizes and inhabitation of only a portion of the range previously ascribed to S. capensis sensu lato. The preponderance of cryptic diversity and endemism in the CFR suggests that additional undescribed cryptic species of obligate freshwater fishes may be found in short coastal river systems around the world, especially in regions with a history of geological stability and a narrow continental shelf.