The chromosome morphology ofArabidopsis thaliana (L.)Heynh. and some remarks on the problem ofHylandra suecica (Fr.) Löve

The chromosome number ofA. thaliana from three localities in Central Bohemia was found to be 2n=10. All the chromosomes (length 1,5–2,6μm) belong to the atelocentric type, four pairs (m) having the centromere in the median and one pair (sm) in the submedian region. In connection with the discussion on the origin ofH. suecica the author presents the following preliminary results: a) the failure to cross the tetraploidCardaminopsis arenosa (L.)Hayek withA. thaliana; b) the successful crossing of the diploidC. petraea (L.)Hiit. withA. thaliana; c) the discovery of a diploid population ofC. arenosa (2n=16) in the Tatra Mts. (Czechoslovakia).     

Chemical constituents with ɑ,β-unsaturated carbonyl group from the whole plants of Erigeron breviscapus (Vant.) Hand.-Mazz. (Asteraceae)

Phytochemical characterization of the whole plants of Erigeron breviscapus (Vant.) Hand.-Mazz. Led to the isolation of two indole derivatives (1–2), seven monoterpenoids (3–9), two sesquiterpenoids (10–11), and four pyrone derivatives (12–15). The structures of these compounds were examined with spectroscopic methods, and also by comparing with previously reported spectroscopic data. Among them, ten compounds (1–2, 6–11, 14–15) are reported from Erigeron breviscapus for the first time. In addition, three compounds (2, 8–9) are isolated for the first time from Asteraceae family. On the basis of chemical research, we also described the chemotaxonomic significance of these compounds.     

Volatile constituents of Erodium cicutarium (L.) L’ Hérit. (Geraniaceae)

Essential oils from Erodium cicutarium were obtained by hydrodistillation (samples consisting of entire plants (ec1), leaves and stems (ec2)) and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS), resulting in a total of 177 components being identified. The essential oils were of a very similar chemical composition and consisted mainly of aliphatic compounds and their derivatives. Fatty acids and fatty acid derived compounds were the most common, 51.3% (ec1) and 60.1% (ec2), followed by carotenoid derived compounds, 12.6% (ec1) and 20.2% (ec2), and then terpenoids, 14.9% (ec1) and 14.2% (ec2). The main constituents in the oils were hexadecanoic acid, 22.8% (ec2) and 35.9% (ec1) and hexahydrofarnesyl acetone, 10.8% (ec2) and 11.6% (ec1). The results obtained differ markedly from those previously reported for the same species.     

Cytotoxic constituents from the leaves of Jerusalem artichoke (Helianthus tuberosus L.) and their structure–activity relationships

Bioassay-directed phytochemical study of the Jerusalem artichoke (Helianthus tuberosus L.) leaves led to the isolation of a new sesquiterpene lactone of 3-Hydroxy-8β-tigloyloxy-1,10-dehydroariglovin (1), ten known sesquiterpene lactones (2–11) and two known flavones (12–13). Their chemical structures were elucidated on the basis of NMR (1D and 2D) and mass spectroscopic analysis. The cytotoxic activities of those compounds were subsequently tested against the MCF-7, A549 and HeLa cancer cells lines. The results indicated that sesquiterpene lactones 1–11 exhibited consistent cytotoxicity against all three cancer cell lines, while flavones 12 and 13 showed selective inhibitory activity against HeLa cell lines. Among them, compound 3 exhibited significant growth inhibitory activity against all three cell lines. The IC₅₀ values of compound 3 against MCF-7, A549 and HeLa were 1.97 ± 0.04, 7.79 ± 0.44, 9.87 ± 0.20 μg/ml, respectively. In addition, some structure–activity relationships of these sesquiterpene lactones for cytotoxicity were explored and summarized in this study.     

Chemical constituents from Dendropanax morbiferus H. Lév. Stems and leaves and their chemotaxonomic significance

The phytochemical investigation of Dendropanax morbiferus H. Lév. Led to the isolation of 28 known compounds: 4 alkaloids (1–4), 1 pyranoglucoside (5), 1 benzoic acid and 5 benzoic acid derivatives (6–11), 10 phenylpropanoids (12–21), 4 flavone glucoside derivatives (22–25), 1 neolignan (26) and 2 sesquiterpenes (27–28). The structures of these compounds were identified using spectroscopic methods; their nuclear magnetic resonance spectra were compared with those previously reported. This is the first report on compounds 2–4, 10, and 12 isolated from D. morbiferus. Compounds 5 and 26 from the genus Dendropanax and 1, 6–9, 11, 13, 14–25, 27 and 28 from the family Araliaceae were isolated for the first time. Additionally, to the best of our knowledge, this is the first comprehensive chemical investigation of D. morbiferus stems and leaf compounds. Chemotaxonomic relationship between D. morbiferus and other Dendropanax species is also discussed.     

Genetic variation and differentiation in Nordic populations of Elymus alaskanus (Scrib. ex Merr.) Löve (Poaceae)

 To gain information on the extent and nature of genetic variation in Elymus alaskanus, levels and distribution of genetic variation were assessed within and among 13 populations originating from Iceland, Norway, Sweden and Russia using allozymes. The results showed that four (30.7%) of the 13 loci were polymorphic within the species, while the mean percentage of polymorphic loci within the populations was 1.9%. The mean number of alleles per locus for the species was 1.8 and 1.02 across the populations. Genetic diversity at the species level was low (H _es=0.135), and mean population diversity was notably lower (H _ep=0.005). A high degree of genetic differentiation was observed among populations. The salient points emerging from this study are: (1) statistically significant differences were found in allele frequencies among populations for every polymorphic locus (P<0.001), (2) the high mean coefficient of gene differentiation (G _ST) showed that 95% of the total allozyme variation was attributable to differences among populations, and (3) relatively high genetic distances between the populations were obtained (mean D=0.16). The Norwegian populations had the highest genetic diversity as compared with the other populations. Geographical comparisons revealed three different groups of populations clearly differentiated, i.e. Scandinavia (Norway and Sweden), Iceland and Russia. Cluster and principal coordinates analyses revealed the same genetic patterns of relationships among populations. Generally, this study indicates that E. alaskanus contains low allozymic variation in its populations. The implications of these results for the conservation of the species are discussed. Received: 23 October 1998 / Accepted: 19 December 1998     

Potent α-glucosidase inhibitors from the roots of Panax japonicus C. A. Meyer var. major

Bioassay-guided fractionation of the CHCl₃ soluble portion of the roots of Panax japonicus C. A. Meyer var. major afforded an active fraction with inhibitory activity against baker’s yeast α-glucosidase with an IC₅₀ value 1.02 mg/mL. Furthermore, the active fraction isolated contained three previously unreported polyacetylenes, designated panaxjapynes A–C, together with 11 other compounds, including four polyacetylenes, five phenolic compounds, a sesquiterpenoid, and a sterol glucoside. The structures of the compounds were elucidated by spectroscopic and chemical methods. Compared with the control acarbose (IC₅₀ 677.97 μM), six compounds were shown to be more potent α-glucosidase inhibitors with IC₅₀ values in the range 22.21–217.68 μM.     

Clestobothrium neglectum (Lönnberg, 1893) n. comb. (Cestoda: Bothriocephalidae) from the tadpole fish Raniceps raninus (L.) (Gadidae) from Sweden

Clestobothrium neglectum (Lönnberg, 1893) n. comb. is redescribed from specimens previously deposited in The Natural History Museum, London, UK by Dr David I. Gibson obtained from the intestine of the tadpole fish Raniceps raninus (Gadidae) collected from off the western coast of Sweden, near Kristineberg. C. neglectum resembles C. crassiceps (Rudolphi, 1819), the type- and only species currently recognised in the genus, but differs in having fine spiniform-like structures that are likely microtriches covering the posterior fourth of the scolex and all proglottids, a highly folded tegument forming numerous longitudinal ridges on both the dorsal and ventral surfaces of the proglottids giving them a scalloped appearance, a somewhat smaller egg (68 × 35 vs 75 × 40 μm), a U-shaped rather than H-shaped ovary and more testes (70–85 vs 40–50 per proglottid). C. neglectum is also compared to two species with similar scoleces that were previously assigned to Clestobothrium, Bothriocephalus acheilognathi Yamaguti, 1934 and B. kivuensis Baer &; Fain, 1958 (considered to be synonymous with B. acheilognathi by Pool, 1987). This is the first report of a species of Clestobothrium Lühe, 1899 (Bothriocephalidae) from a gadid fish.     

The inheritance of β-amylase null in storage roots of sweet potato,Ipomoea batatas (L.) Lam.

Summary Several sweet potato genotypes were found to lack completely or to have only traces of-amylase in their storage roots. Such genotypes do not increase in sweetness during cooking because, without a sufficient amount of-amylase, the normal hydrolysis of starch to maltose does not occur in the cooking process. In order to study the inheritance of this biochemical variant in the genotype, 41 families were generated. The following conclusions were drawn from analyzing these families. (1) This trait is controlled by one recessive allele (designated-amy) (2) It is inherited in a hexasomic or tetradisomic manner, but not disomically or tetrasomically. This conclusion supports previous cytological data that sweet potato is an autohexaploid or has two identical genomes plus one genome which is somewhat different. (3) The-amy allele appears to exist at a high frequency in cultivated germplasm. (4) Breeding sweet potato for low-amylase activity is relatively easy. New types of sweet potato without normal-amylase activity have great potential for processing and as a staple food.     

The Discovery of Diploid Lycoris radiata (L′Her.) Herb. from Anhui

Lycoris radiata (L′Her. ) Herb. containing wild and cultural types, is distributed in China and Japan. The karyotype variation in three populations of the species from Anhui is studied in this paper. (1) Wuhu wild population has a karyotype 2n=21+1B= 1m+12st +8t+1B. The chromosomes range in length from 7.50 to 14.10 µm with the ratio of the longest to the shortest 1.88. The karyotype belongs to Stebbins’(1971) 3A. (2) Huangshan wild population has two cytotypes: 2n=22 and 2n=22+1B. Type Ⅰ: The karyotype formula is 2n=22=12st+10t. The chromosomes range in length from 6.85 to 9.95 µm. with the ratio of the longest to the shortest 1.45. The karyotype belongs to 4A. Type Ⅱ: The karyotype formula is 2n=22+1B=6st+14t+2T+1B (plate 1: 7,8). The chromosomes range in length from 6.50 to 11.02 µm. with the ratio of the longest to the shortest 1.70. The karyotype belongs to 4A. (3) Wuhu cultural type has a karyotype 2n=33=30st +3t. The chromosomes range in length from 7.10 to 9.35 µm with the ratio of the longest to the shortest 1.32. The karyotype belongs to 4A. This result agrees well with the previous reports. The diploid types of Lycoris radiata (L´Her.) Herb. are found in Anhui for the firsttime.     

Creatine kinase from the electric organ of Electrophorus electricus (L.)—isozyme analysis

• 1.1. Creatine kinase (CPK) isozymes of extracts from the electric organ, dorsal muscle and brain of Electrophorus electricus (L.) were analysed with Cellogel electrophoresis. A single component corresponding to the MB-form was obtained for both electric organ and the dorsal muscle. The BB-form was present in the brain extract.
• 2.2. Upon acetone fractionation of the aqueous extract of electric organ, the final fraction was submitted to gel filtration and presented a single peak of CPK activity.
• 3.3. Characterization of this fraction by thin-layer gel filtration indicated an apparent molecular weight of 80,000 which corresponds to the enzyme dimeric structure.
• 4.4. The implications of this finding with the muscular origin of the electric organ are discussed.

     

Inheritance of resistance to the two-spotted spider mite from L. pimpinellifolium (Jusl.) Mill. accession ‘TO-937’

The two-spotted spider mite (Tetranychus urticae Koch) is an important pest of tomato (Lycopersicon esculentum Mill.) crops in temperate regions as this spider mite has a very large capacity for population increase and causes severe tomato yield losses. There is no described tomato cultivar fully resistant to this pest, although resistant accessions have been reported within the green-fruited tomato wild species L. pennellii (Corr.) D’Arcy and L. hirsutum Humb. & Bonpl. We observed a L. pimpinellifolium (Jusl.) Mill. accession, ‘TO-937’, which seemed to be completely resistant to mite attacks and we crossed it with the susceptible L. esculentum cultivar. ‘Moneymaker’ to obtain a family of generations consisting of the two parents, the F₁, the F₂, the BC₁ to L. esculentum, and the BC₁ to L. pimpinellifolium. This family was evaluated for mite resistance in a polyethylene greenhouse using an experimental design in 60 small complete blocks distributed along 12 double rows. Each block consisted of five F₂ plants in one row and one plant of each of the two parents, the F₁, the BC₁ to L. esculentum, and the BC₁ to L. pimpinellifolium in the adjacent row. Plants at the 10–15 leaf stage were artificially infested by putting on them two pieces of French bean leaf heavily infested with T. urticae. After two months, evaluations of infestation were made by visual observation of mite nets and leaf damage. Plants that were free of signs of mite reproduction on the top half were considered as resistant, plants with silky nets only on their basal leaves, intermediate, and plants with mite reproduction on both basal and top canopies were scored as susceptible. Dominance for resistance appeared because all the ‘To-937’, BC₁ to L. pimpinellifolium, and F₁ plants were resistant. Not all ‘Moneymaker’ plants behaved as susceptible because 35% of plants were intermediate. In the BC₁ to L. pimpinellifolium and the F₂, most plants were scored as resistant, only 7 % BC₁ and 3 % F₂ plants were intermediate, and a single F₂ plant (0.3 %) was susceptible. With these figures, resistance seemed to be controlled by either four or two genes according to whether segregation in the BC₁ or in the F₂, respectively, were considered. These results could in part be explained because of appearance of negative interplot interference due to the high frequency of resistant genotypes within most of the generations. Therefore, the family was evaluated again but using a different experimental design. In the new experiment, 16 ‘TO-937’, 17 ‘Moneymaker’, 17 F₁, 37 BC₁ to L. pimpinellifolium, 38 BC₁ to L. esculentum, and 125 F₂ plants were included. Each of these test plants was grown besides a susceptible ‘Moneymaker’ auxilliary plant that served to keep mite population high and homogeneous in the greenhouse. Negative interplot interference was avoided with this design and all the ‘TO-937’, F₁, and BC₁ to L. pimpinellifolium plants were resistant, all ‘Moneymaker’ test plants were susceptible, and 52 % BC₁ to L. esculentum and 25 % F₂ plants were susceptible, which fitted very well with the expected for resistance governed by a single dominant gene. The simple inheritance mode found will favour sucessful introgression of mite resistance into commercial tomatoes from the very close relative L. pimpinellifolium.     

Oxytrofalcatins A–F,N-benzoylindole analogues from the roots of Oxytropis falcata (Leguminosae)

Indole alkaloids, oxytrofalcatins A–F (1–6), together with five other known alkaloids (7–11), were isolated from the roots of Oxytropis falcata. Their structures were elucidated by comprehensive spectroscopic analyses, including using 1D and 2D NMR spectroscopy and mass spectrometry. This is the first report of N-benzoylindoles from a natural source. Compounds 1–6 lacked significant cytotoxicity against SGC-7901 and HL-60 tumor cell lines.     

Somatic embryogenesis and shoot regeneration from excised adventitious roots of the rootstock Rosa hybrida L. ‘Moneyway’

Plants were regenerated from excised adventitious roots of the rose rootstock Moneyway via a three step procedure: callus induction, induction of somatic embryos and shoot development. Callus was induced on excised roots after incubation for 4 weeks in the dark on SH-medium (Schenk and Hildebrandt) containing 50 M 2,4-dichlorophenoxyacetic acid. For embryo induction, calluses were transferred to hormone-free SH-medium and incubated for 8 weeks. The use of Gelrite instead of agar during callus induction stimulated somatic embryogenesis (up to 16% of the explants formed organized structures), whereas the presence of 6-benzylaminopurine in this phase inhibited subsequent regeneration. Yellow solid calluses with embryo-like cotyledons or primordia and friable calluses with embryos were selected, and upon incubation in the light shoots developed. Shoot development was faster and more frequent on solid callus than on friable callus (64% and 21% of the calluses finally formed one or more shoots, respectively). Eleven out of thirteen regenerants developed similarly to control shoots. Finally this regeneration method is compared with other systems for somatic embryogenesis and opportunities for the production of transgenic rose rootstocks and rose cultivare are discussed.Abbreviations BAP 6-benzylaminopurine - BM basal medium - BM+ enriched basal medium - 2,4-D 2,4-dichlorophenoxyacetic acid - DAPI-4,6 diamidino-2-phenylindole - FeEDDHA ferric ethylenediamine di(ohydroxyphenylacetate) - FeEDTA ferric ethylenediamine tetraacetate - IBA indole-3-butyric acid     

Hybrids and backcross progenies between wheat (Triticum aestivum L.) and apomictic Australian wheatgrass [Elymus rectisetus (Nees in Lehm.) A. Löve & Connor]: karyotypic and genomic analyses

Wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD) florets were emasculated and pollinated using two apomictic wheatgrass [Elymus rectisetus (Nees in Lehm.) A. Love & Connor, 2n = 6x = 42, SSYYWW] accessions, one of which produces 2n pollen. A 2n = 42 (B_II) hybrid and four 2n = 63 (B _III) hybrids were obtained. The spike morphology of the B _II hybrid was intermediate to that of its parents. The pollen mother cells (PMCs) of this hybrid contained on average 38.361 and 1.62 II, which was consistent with its disparate genome composition (ABDSYW). Its pollen failed to stain and no BC₁ progeny was obtained. The B _III hybrids (reduced egg fertilized with unreduced sperm) were grasslike and had a full complement of E. rectisetus chromosomes, the synapsis of which was slightly impaired by wheat haplome and/or cytoplasm. Their PMCs contained on average 16.30 II, 25.72 I, and 1.54 multivalents (III plus IV). Pollen stainability in these hybrids was low (<1%), and when they were used as females, one 54- and 60-chromosome BC₁ were obtained. A mean of 13.25 II was observed in PMCs of the 54-chromosome BC₁ and pollen stainability was 10%. Pollen stainability in the 60-chromosome BC₁ was only 5%. The use of 2n-pollen-producing E. rectisetus accession accelerated hybrid and BC₁ formation and may accelerate the ultimate transfer of apomixis to wheat.     

Are Aristolochic Acids Responsible for the Chemical Defence of Aposematic Larvae of Battus polydamas (L.) (Lepidoptera: Papilionidae)?

Aristolochic acids (AAs) are thought to be responsible for the chemical protection of the aposematic larvae Battus polydamas (L.) (Papilionidae: Troidini) against predators. These compounds are sequestered by larvae from their Aristolochia (Aristolochiaceae) host plants. Studying the role of the chemical protection of the second and fifth instars of B. polydamas against potential predators, we found that the consumption of larvae by the carpenter ant Camponotus crassus Mayr and young chicks Gallus gallus domesticus was dependent on larval developmental stage. Second instars were more preyed upon than fifth instars; however, the assassin bug Montina confusa Stål was not deterred by chemical defences of the fifth instar B. polydamas. Laboratory bioassays with carpenter ants and young chicks using palatable baits topically treated with a pure commercial mixture of AAs I and AAs II in concentrations up to 100 times those previously found in B. polydamas larvae showed no activity. Similar results were found in field bioassays, where palatable baits treated as above were exposed to the guild of predators that attack B. polydamas larvae and were also consumed irrespective of the commercial AA concentration used. These results suggest that the mixture of AAs I and AAs II have no defensive role against predators, at least against those investigated in the present work. Other compounds present in Aristolochia host plants such as O-glycosylated AAs; benzylisoquinoline alkaloids; and mono-, sesqui-, di-, and triterpenes, which can be sequestered by Troidini, could act as deterrents against predators.