Low incidence of polyploids and high uniformity of karyotypes displayed by Delphinium (Ranunculaceae) in the Hengduan Mountains region of south‐west China

The chromosome numbers and morphology in 92 populations belonging to 49 species and three varieties in the genus Delphinium L. (Ranunculaceae), mostly from the Hengduan Mountains region of south‐west China, were studied. Forty seven species and three varieties were diploid, with 2n = 16, one species was tetraploid, with 2n = 32, and one species had diploid and tetraploid cytotypes. Three species had B chromosomes, representing the first time the occurrence of B chromosomes has been reported in the genus. The karyotypes of all the diploid species were quite uniform, commonly bimodal, and usually consisted of one pair of large median‐centromeric (m), one pair of large submedian‐centromeric (sm), five pairs of medium‐sized subterminal‐centromeric (st), and one pair of smaller sm (rarely st) chromosomes. The low incidence of polyploids in Delphinium from the Hengduan Mountains region indicates that polyploidy has played a minor role in the speciation of this highly diversified genus in the region. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 172–188.     

Karyological studies in Jaborosa (Solanaceae)

Sixteen species of Jaborosa (Solanaceae), including eight endemic to Argentina, were studied karyologically. The numbers n  = 12 and/or 2n  = 24 were found in all species, the majority of the cases being new reports. Mitotic chromosomes were small- to medium-sized, the average length varying from 2.95 to 4.93 µm. All species had one to three chromosome pairs with satellites. The karyotypes, obtained for 13 species, were slightly asymmetrical: A ₁ ranged from 0.228 to 0.483, A ₂ ranged from 0.095 to 0.182, and Paszko's asymmetry index ranged from 0.84 to 3.47. In all species, metacentric chromosomes were the most common, followed by submetacentrics, but subtelocentrics were rare. Morphological similarities and sectional arrangements were not reflected in either a principal components analysis plot or asymmetry index plot, but the species could be singled out by their karyotype formulae and the different karyotype parameters taken. In Jaborosa , a notably diversified genus, exo-morphological evolution has taken place, together with evident chromosome rearrangements, whose disposition is different and not as clear as in related genera.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 467–478.     

Karyology of Aconitum subgenus Lycoctonum (Ranunculaceae) from China,with a report of the new base chromosome number x = 6 in the genus Aconitum

In order to gain better knowledge of the number and morphology of chromosomes in Aconitum subgen. Lycoctonum in China, 60 populations belonging to 20 species were cytologically studied. Chromosome numbers of six species (A. apetalum, A. finetianum, A. fletcheranum, A. longecassidatum, A. umbrosum and A. wangyedianense) are here reported for the first time. One species, A. fletcheranum, has 2n = 12, and thus is a diploid based on x = 6, a new base chromosome number for the genus Aconitum. Most of the remaining taxa are diploid (2n = 16) based on x = 8, but five taxa (A. angustius, A. brevicalcaratum var. brevicalcaratum, A. brevicalcaratum var. parviflorum, A.chrysotrichum and A. crassiflorum) are tetraploid with 2n = 32, and one species (A. apetalum) is hexaploid with 2n = 48, the highest ploidy level currently known in the subgenus. Disregarding differences in the presence or absence and number of satellites, the karyotypes of all the 2n = 16 species are quite uniform (2n = 2m + 6sm + 8st), but A. novoluridum, the only species of A. section Alatospermum, has an intrachromosomally less asymmetric karyotype (2n = 2m + 14sm), which lends further support for the primitive condition of its section as inferred from gross‐morphology. Chromosomal variation in the subgenus and the relationships of some of the species are discussed.     

Karyological studies in Tripleurospermum (Asteraceae, Anthemideae) from north-east Anatolia

Chromosome number and morphology in 14 taxa belonging to 19 populations of Tripleurospermum Sch. Bip. were studied using karyological and numerical taxonomical techniques. Data on chromosome measurements were analysed using cluster analysis. Chromosome numbers of these taxa are 2 n  = 2 x  = 18, 4 x  = 36 and 5 x  = 42–48. Seven records are new, two are not consistent with previous counts, and the remainder confirm the very limited previous data (one to three records). A new ploidy level (pentaploidy) is reported for the first time for the genus. Some correlations between ploidy levels and morphological characters are noted and several systematic and evolutionary aspects of the genus are discussed in the light of karyological data.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 146 , 427–438.     

Polyploidy and karyotype variation in Turkish Bellevalia (Hyacinthaceae)

There are 20 Bellevalia species in Turkey, half of which are endemic. Chromosome numbers are known for 15 species. A chromosome survey of 145 Bellevalia individuals showed that the karyotype is remarkably stable. All are based on x  = 4. The majority are diploid with 2 n  = 8, but there is also a polyploid series of 2 n  = 16, 24 and 32. Aneuploidy occurs only at the octoploid level. Eleven individuals had metacentric B chromosomes, one had acrocentric Bs and one had telocentric Bs. Bellevalia pycnantha and B. paradoxa are morphologically similar, with B. pycnantha reduced to a synonom of B. paradoxa .  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 87–98.     

New or rare chromosome counts in the genus Artemisia L. (Asteraceae, Anthemideae) from Armenia and Iran

Nineteen chromosome counts of 12 Artemisia species are reported from Armenia and Iran. Three of them are new reports, sewn are not consistent with previous counts and the remaining are confirmations of very scarce (one to three) previous data. Two basic chromosome numbers (x = 8 and 9) were found, each with several ploidy levels. Chromosome number reduction arising from fusion homozygosity was noted, confirming earlier studies.     

New or rare chromosome counts in the genera Artemisia L. and Mausolea Bunge (Asteraceae, Anthemideae) from Uzbekistan

Seventeen chromosome counts of 14 Artemisia and one Mausolea species are reported from Uzbekistan. Five of them are new reports, two are not consistent with previous counts and the remaining are confirmations of very scarce (one to four) previous data. Two basic chromosome numbers (x = 8 and x = 9) and two ploidy levels (2x and 4x) were found. Some correlations between ploidy level, morphological characters and distribution are noted.     

Karyomorphology of the endangered Trigonobalanus doichangensis (A. Camus) Forman (Fagaceae) and its taxonomic and biogeographical implications

Cytological studies were carried out for the first time on five populations of Trigonobalanus doichangensis in China and Thailand. In all populations, the pattern of interphase nuclei was of the simple chromocentre type, the mitotic prophases were of the proximal interstitial type and chromosome numbers were 2 n  = 2 x  = 14. Two B chromosomes were commonly observed at prophase and prophase–metaphase, but rarely at metaphase. Karyotype variation among the populations at the diploid level was limited, but there were some distinguishing cytological characters. Based on the comparison of all the available data on cytology, taxonomy, phytogeography and molecular systematics related to the genus Trigonobalanus , we recommend that the three species of Trigonobalanus comprise the subfamily Trigonobalanoideae and that the genus should not be segregated into three monotypic genera.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 321–330.     

Cytogeography of European perennial species of Cyanus (Asteraceae)

To reveal the general cytogeographical pattern of Cyanus section Protocyanus in Europe, DNA ploidy and/or chromosome numbers were newly examined for 160 populations by flow cytometry (450 plants) and/or chromosome counting (30 plants). Furthermore, previously published karyological data were revised (236 records). Our analyses confirmed chromosome counts of 2n = 22 for all newly investigated samples of the C. triumfetti group (the records for C. semidecurrens and C. ternopoliensis are new), C. diospolitanus and C. achtarovii; 2n = 44 for C. montanus and C. mollis; and 2n = 20 for C. lingulatus, C. napulifer, C. nissanus, C. orbelicus, C. thirkei, C. tuberosus and C. velenovskyi. The chromosome count of 2n = 20 is the first report for C. epirotus. The cytotype 2n = 40 was newly recorded for the Crimean endemic C. fuscomarginatus and Calabrian and Greek populations of C. graminifolius. The cytotypes 2n = 20 and 2n = 40 were confirmed for C. pindicola. For the first time triploidy (2n～3x～30) was found in C. nissanus, C. thirkei and in a newly discovered hybrid, C. epirotus × C. graminifolius. Two contrasting ecogeographical patterns emerged: cytotypes derived from the base chromosome number x = 11 (2n = 22, 44) are widespread in northern latitudes and ecologically diverse, whereas cytotypes with x = 10 (2n = 20, 30, 40) are confined to mountains in southern Europe. In general, tetraploids have smaller ranges than diploids. The new combinations Cyanus section Protocyanus (Dobrocz.) Ol?avská comb. nov. and Cyanus ternopoliensis (Dobrocz.) Ol?avská comb. nov. are provided. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 230–257.     

Triploidy in Equisetum subgenus Hippochaete (Equisetaceae, Pteridophyta)

BACKGROUND AND AIMS: The genus Equisetum is cytologically uniform, having a base chromosome number of x = 108. All previously known species and hybrids that have been counted represent diploids with a sporophytic chromosome number of 2n = 216. Biosystematic studies on Equisetum subgenus Hippochaete revealed evidence that triploids occur in nature. The objective of this study was to confirm that triploid plants exist in the natural environment. METHODS: Flow cytometry was used to establish nuclear DNA values and cytological investigations of meiosis were carried out to obtain information on chromosome number and pairing behaviour. KEY RESULTS: Triploidy exists in three morphologically different hybrid taxa. Two of these are morphologically intermediate between a primary diploid hybrid and a parent, while the third apparently combines genomes from all three Central European Hippochaete species. Nuclear 1C DNA values for the four European Hippochaete species range from 21.4-31.6 pg. For the hybrids, the 1C DNA values not only occupy the same range as the species, but their total DNA amounts agree closely with values predicted by adding the 1C DNA values of each parental genome. Chromosome counts confirm diploidy in the species E. hyemale and E. variegatum and in the hybrid E. xtrachyodon (= E. hyemale x E. variegatum). For the triploids (2n approximately 324), cytological information is presented for the first time. CONCLUSIONS: Triploid taxa may have originated by backcrossing or by crossing of a diploid hybrid with an unrelated diploid species. As tetraploid plants are unknown, these crossings probably involve diploid gametophytes that developed from unreduced diplospores. By repeated crossing events or backcrossing, reticulate evolution patterns arise that are similar to those known for a number of ferns and fern allies.     

Chromosome numbers in Compositae. XVIII.

Chromosome numbers and other cytogenetic data were determined from microsporocytes in 316 collections including 13 tribes of Compositae, mostly from Africa, Australia, Mexico, Central America, and South America. First reports are provided for 66 species and the genera Cassinia (2n ≈ 14_II), Feldstonia (2n = 11_II), Gochnatia (2n ≈ 23_II), and Pseudoconyza (n = 10). In addition, new chromosome numbers are established at the generic level in Acourtia, Calea, Craspedia, Gnaphalium, Helipterum, Liabum, Leucheria, Smallanthus, Trixis, and Viguiera and at the specific level in 13 additional species.     

Five new alkaloids from Aconitum apetalum (Ranunculaceae)

Twenty-one alkaloids, including five new ones, acoapetaldines A–E (1–5), were isolated from the whole plants of Aconitum apetalum. Among them, 1 is an aconitine-type diterpenoid alkaloid, 2 and 3 are aporphine alkaloids and 4 and 5 are napelline-type diterpenoid alkaloids. The structures of the new alkaloids were elucidated by spectroscopic data analysis and that of acoapetaldine D (4) was confirmed by single crystal X-ray crystallography. Acoapetaldine A (1) and aconorine (12) exhibited moderate anti-tobacco mosaic virus (anti-TMV) activity, while corydine (15) displayed moderate antimicrobial activity against Pseudomonas aeruginosa.     

Allozyme variation and population differentiation of the Aconitum delavayi complex (Ranunculaceae) in the Hengduan Mountains of China

The Aconitum delavayi complex is a group of four climbing species with trisect-leaves occurring in the Hengduan Mountains. The species of this complex are highly localized on very narrow regions with quite small population sizes. Because of rapid environmental changes recently in the Hengduan Mountains, this complex shows complicated morphological variability, which makes it difficult to delimit species. In the present study, 10 enzyme systems coding for 14 putative loci were employed to detect the interspecific and intraspecific genetic variation of the complex. In addition to low genetic diversity within all eight populations surveyed, the results indicate that A. episcopale is a distinct species because of high genetic identities among its three populations. Very low genetic divergence among populations of A. stapfianum and A. delavayi suggests that the two species should be treated as a single one.     

Interpopulation variation in nectar production in Aconitum columbianum (Ranunculaceae)

Summary In Aconitum columbianum there are extreme interpopulation differences in rates of nectar secretion per flower. Since nectar sugar concentration varies little among populations, increased nectar secretion results in a greater mass of sugar per flower for pollinator attraction. These differences in the amount of reward offered per flower account at least in part for observed higher levels of pollinator activity in populations with high nectar production. Nectar production is correlated also with nectary depth, i.e., flowers in populations with deep nectaries have higher rates of nectar secretion than those with shallow nectaries. Nectary depth differences adapt populations to different pollinator-types. Populations with deeper nectaries are adapted to pollination by bumblebees with longer tongues and more specialized foraging behaviors. In conclusion, there are basic differences in pollination ecology among geographical races of a. columbianum, which are indicated by correlated interpopulution differences in (1) nectar production, (2) level of pollinator activity, (3) nectar depth, and (4) pollinator-type.     

Karyological studies on the Sino-Himalayan genus, Cremanthodiurn (Asteraceae: Senecioneae)

Twenty-two populations of seven species of Cremanthodium from high altitude regions of western China were observed karyologically. C. ellisii, C. microglossum, C. brunneo-pilosum, C. stenoglossum, C. discoideum and C. lineare all had the same chromosome number of 2 n = 58 whereas C. humile had 2 n = 60. All chromosome numbers of these species are documented here for the first time. The basic number of x = 30 is new for this genus. The karyotypes of all species belong to 2A type according to Stebbins' asymmetry classification of karyotypes. Two basic chromosome numbers, x = 30 and x = 29 in Cremanthodium , correspond exactly to two branching patterns in this genus, sympodial versus monopodial. The systematic and taxonomic statuses of the sympodial species need further study. The karyomorphological data provide no support to the sectional subdivision in Cremanthodium .     

Polytene chromosomes of an archipelagic subgenus, <Emphasis Type="Italic">Inseliellum</Emphasis> (Diptera: Simuliidae)

The black fly subgenus Inseliellum is present on a series of archipelagos in the South Pacific. In this study, larval polytene chromosome maps of six Inseliellum species are presented. Chromosomal relationships among taxa were determined through shared fixed inversions or chromosomal landmark positioning. Three fixed inversions (IL-2, IIS-1, and IIIS-1) were shared among species, as was the position of the nucleolar organizer (NO) (IL or IIL). Comparisons to two previously studied species of Inseliellum are included to produce a cytological transformation series among eight taxa. The NO position defines two clades in the phylogeny of Inseliellum, herein named the NO-IL and NO-IIL clades. The utility of this cytological data set is discussed.     

草乌传粉过程中的广告效应与回报物质研究

虫媒传粉植物与其传粉者之间的相互作用被认为是被子植物花多样性的一个重要选择压力。这种相互作用体现在植物对传粉者的吸引以及传粉者行为对花粉的转运两个方面。本项研究通过去除不同的花部器官研究了草乌(Aconitum kusnezoffii)对其传粉者的吸引, 并结合传粉者的访问行为和草乌花的生物学特性探讨了传粉过程与交配系统的适应。红光熊蜂(Bombus ignites)是草乌的有效传粉者。去除花萼片显著降低了红光熊蜂的访问频率, 但去除特化成蜜腺叶的花瓣并没有显著改变红光熊蜂的访问频率, 这表明草乌吸引红光熊蜂的主要结构是由5枚萼片组成的花部外观形态, 而非花瓣。花蜜是草乌提供给红光熊蜂的回报物质, 糖浓度为39.23%, 组氨酸浓度为0.25 μg/μL。草乌花较大、单花花期长、雌雄异熟、花粉寿命长, 是一个自交亲和但需传粉者传粉完成繁殖过程的异交物种。草乌花序是无限花序, 当上部的花处于雄性阶段时, 下部的花正好处于雌性阶段。而红光熊蜂在草乌花序上的访问顺序通常自下而上, 带来异交花粉为下部的花进行异花授精, 同时又带走上部花的花粉, 这就很好地促进了草乌的异交。草乌雄蕊自外向内逐渐成熟, 是一种有效的限制传粉者单次访问浪费大量花粉的花粉装配策略, 能提高植物通过花粉散布获得的雄性适合度。     

四川乌头属二新种

描述了自四川西部发现的毛茛科乌头属二新种,细盔乌头和疏叶乌头,并给出其等与近缘种的区别特征。