The Pollination Biology of Heloniopsis orientalis (Thunb.) C. Tanaka (Liliaceae)

Abstract The pollination biology of Heloniopsis orientalis was investigated in the lowlands of south central Japan. The receptive stigma emerges from the perianth before the opening of the perianth, and anther dehiscence is late about two days for perianth opening. The flower therefore is protogynous even though no insects visit the unopen flowers. Receptivity of the stigma is maintained for about 8 days, and even the 10 day-old flower can produce seeds. Self-pollination may be rather common in H. orientalis , which is self-compatible, in particular in the flowers which open on days unfavorable for insect activity. Many species of Diptera and Hymenoptera forage on the flowers, and almost any insect can be their pollinator. Long life, self-compatibility of the flowers, and many kinds of pollinators seem to be factors favoring H. orientalis , which blooms in very early spring when the pollinator supply is unstable but which nevertheless bears many seeds.     

Population dynamics ofHeloniopsis orientalis C. Tanaka (Liliaceae) in natural forests — Sexual reproduction

This study investigated the effects of climate on reproduction, consecutive flowering, and the level of energy investment toward sexual reproduction, as well as the relationships between flowering rates and plant size, and between seed production and plant size. The target species wasHeloniopsis orientalis C. Tanaka (Liliaceae), an evergreen perennial herbaceous plant. Natural populations were monitored in permanent quadrats for seven years in a low-elevation area (Namhansanseong) and for five years in an area with a high elevation (Maranggol). The Tn indices required for flowering were relatively similar each year, but those for seed dispersal fluctuated. The period for seed production was proportional to the total length of the growing season. Rates of flowering varied annually, and depended on conditions in each study area. Flowering was discontinuous (i.e., not consecutive) at Namhansanseong, but was continuous (i.e., consecutive) at Maranggol. The rates were proportional to plant size; the minimum size class that supported flowering was 60–90 cm², and almost all plants with >210 cm² leaf area flowered. The overlapping range in plant size between flowering and non-flowering plants was relatively broad. Numbers of fruit per plant ranged from 1-12, with an average of 6.0 fruits at Namhansanseong and 5.0 fruits at Maranggol. In the latter area, the range in the number of seeds produced and their weight per plant varied drastically, being 1700–1867 seeds and 133.2–177.5 mg, respectively. Almost all correlation coefficients between plant size and fruit number, plant size and seed number, or plant size and seed weight were significant at the 1% level. Lastly, energy investment rates for sexual reproduction were about 30–50% of the net productivity, varying over the years. These rates were proportional to growth rates.     

Karyotype differentiation in three species of Tripogandra Raf. (Commelinaceae) with different ploidy levels

Most species of the genus Tripogandra (Commelinaceae) are taxonomically poorly circumscribed, in spite of having a relatively stable basic number x = 8. Aiming to estimate the cytological variation among Tripogandra species carrying this base number, several structural karyotypic characters were investigated in the diploid T. glandulosa, the hexaploid T. serrulata, and the octoploid T. diuretica. A careful evaluation of chromosome size and morphology did not reveal clear chromosome homeologies among karyotypes. The mean chromosome size was strongly reduced in the octoploid species, but not in the hexaploid species. They also differed largely in the CMA(+) banding pattern and in the number of 5S and 45S rDNA sites per monoploid chromosome complement. All three species showed proximal DAPI (+) heterochromatin, although in T. serrulata this kind of heterochromatin was only visible after FISH. Further, the meiosis in T. serrulata was highly irregular, suggesting that this species has a hybrid origin. The data indicate that, in spite of the conservation of the base number, these species are karyologically quite different from each other.     

Chromosome numbers and DNA ploidy levels of selected species ofHieracium s.str. (Asteraceae)

Chromosome numbers and /or ploidy levels are reported for 44 species and subspecies ofHieracium s.str. from the following European countries: Andorra, Austria, Bulgaria, Czech Republic, France, Italy, Montenegro, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland and Ukraine. The chromosome numbers/DNA ploidy levels ofH. bocconei (2n ～ 4x),H. bupleuroides subsp.leviceps (2n = 27),H. caesioides subsp.caesioides (2n = 27),H. basifolium (H. caesium agg., 2n = 36),H. plumbeum (H. caesium agg., 2n = 36),H. glaucum subsp.nipholepium (2n= 27),H.gouanii (2n = 18),H. gymnocerinthe (2n = 27),H. ramondii (2n = 27),H. recoderi (2n = 18),H. stelligerum (2n = 18), andH. tomentosum (2n = 18, 2n ～ 2x, 2n ～ 3x) were determined for the first time. New ploidy levels are reported forH. cerinthoides s.str. (2n = 27),H. humile (2n = 36), andH. tommasinianum (2n = 27).     

Patterns of endopolyploidy and 2C nuclear DNA content (Feulgen) inScilla (Liliaceae)

The Feulgen-DNA content of 3558 nuclei from 21 different tissues and organs ofScilla decidua (Liliaceae) was measured by a scanning cytophotometer interfaced to a computer. The basic nuclear DNA content (2 C value) was 13.62 pg, and 71 per cent of the nuclei were polyploid. The highest DNA values were found in the antipodal cells of the ovule, and the elaiosomes of the seeds (512 C). In addition to polyploidy, the 2 C values exhibited tissue-specific variation which was statistically significant (0.05% level of probability), It is suggested that differential DNA replication and endopolyploidization may be basic factors in the complex mechanism of cell and tissue differentiation.Dedicated to Professor Dr.Lothar Geitler in honour of his 80th birthday.     

Multivariate studies of Ipheion (Amaryllidaceae, Allioideae) and related genera

Ipheion, as recognized by Guaglianone (Darwiniana 17:159–242, 1972), is a small genus of the family Amaryllidaceae, subfamily Allioideae, tribe Gilliesieae endemic to South America. Since 1800, the species of Ipheion were treated under Beauverdia, Brodiaea, Milla, Nothoscordum, Tristagma or Triteleia. Nowadays, some species of Ipheion are treated as Tristagma and some other under Nothoscordum. In this paper, we analyzed the morphological variation among species of Ipheion and related genera using a numerical taxonomic approach based on overall similarity, to investigate the intergeneric and infrageneric variations to the circumscribed groups. Based on 141 operational taxonomic units and 51 morphological characters, multivariate analyses were performed. Results showed that Ipheion separated into two groups according to Guaglianone’s sectional treatment: Ipheion sect. Ipheion is morphologically more similar to the studied species of Tristagma, while I. sect. Hirtellum can be separated from Nothoscordum/Zoellnerallium and from Tristagma and allies. These a priori groupings were tested using discriminant and univariate analyses. Diagnostic characters were selected to differentiate groups. Previous taxonomic treatments are discussed and results are also evaluated using additional karyological and geographical data.     

Biosystematic studies inTulipa sect.Eriostemones (Liliaceae)

Evolutionary relationships and infra- and interspecific variability within the species ofTulipa sect.Eriostemones Boissier were studied. Measurements of 35 morphological characters were used for principal component and canonical variate analyses. Crossing experiments and chromosome counts were carried out. Two axes of morphological variation were encountered within the principal component plot. Variation of subsect.Biflores was traced along one axis, the species of subsect.Australes as well asSaxatiles were found along the other axis. The nomenclature of names of subsect.Biflores was considered on the basis of their geography, specific morphological characteristics and polyploidy. Conspecificity of names of all species was tested based on both morphology and crossability.     

Hybrid zones between invasive Rorippa austriaca and native R. sylvestris (Brassicaceae) in Germany: ploidy levels and patterns of fitness in the field

Hybrid zones may serve as natural laboratories for evolutionary studies. One common viewpoint is that hybrids may always be less fit than their parents due to genetic discontinuities. An alternative idea is that genotype-environment interactions influence the outcome of natural hybridization. Our comparative study of two different natural hybrid zones between the invasive diploid Rorippa austriaca and the native polyploid R. sylvestris in Germany identified the ploidy level as a major determinant of hybrid fitness. Different ploidy levels and patterns of fitness were detected in different hybrid zones. In one hybrid zone (Mülheim, Ruhr valley) hybrids were pentaploid and showed a relatively high seed set, whereas in the second hybrid zone (Randersacker, Main valley) hybrids were triploid and displayed extremely low fitness values. Analyses of fitness values in different natural hybrid zones between the same two species may lead to very different conclusions about the evolutionary significance of natural hybridization.     

Embryological observations on Helichrysum rupestre (Rafin.) DC. var. errerae (Tineo) Pignatti

Abstract

The ovule and anther development of Helichrysum rupestre var. errerae from Pantelleria is studied. The ovule is anatropous, tenuinucellate, unitegmic, endotheliate and is derived from a two-zonate primordium. The archespore is one- or two-celled and all the megaspores show a functional tendency, although only the chalazal one is able to form the gametophyte according to the Polygonum type. The polar nuclei fuse before fertilization and the three antipodal cells divide further. Anthers are tetrasporangiate and their wall development conforms to the Dicotyledonous type. The epidermis persists at maturity and the endothecial cells thicken their walls. The tapetum is of the periplasmodial type and its cells become plurinucleate during microsporogenesis. The number of microsporocytes varies along the length of the same locule. Arrangement of the resulting microspores is tetrahedral, isobilateral or decussate. Pollen grains are three-celled when shed. Degenerating microsporocytes and microspores have frequently been found.     

Special Issue in Honor of Dr. Graham A. R. Johnston

Dedication

Special Issue in Honor of Dr. Graham A. R. Johnston     

Mating system and ploidy influence levels of inbreeding depression in Clarkia (Onagraceae)

Inbreeding depression is the reduction in offspring fitness associated with inbreeding and is thought to be one of the primary forces selecting against the evolution of self-fertilization. Studies suggest that most inbreeding depression is caused by the expression of recessive deleterious alleles in homozygotes whose frequency increases as a result of self-fertilization or mating among relatives. This process leads to the selective elimination of deleterious alleles such that highly selfing species may show remarkably little inbreeding depression. Genome duplication (polyploidy) has also been hypothesized to influence levels of inbreeding depression, with polyploids expected to exhibit less inbreeding depression than diploids. We studied levels of inbreeding depression in allotetraploid and diploid species of Clarkia (Onagraceae) that vary in mating system (each cytotype was represented by an outcrossing and a selfing species). The outcrossing species exhibited more inbreeding depression than the selfing species for most fitness components and for two different measures of cumulative fitness. In contrast, though inbreeding depression was generally lower for the polyploid species than for the diploid species, the difference was statistically significant only for flower number and one of the two measures of cumulative fitness. Further, we detected no significant interaction between mating system and ploidy in determining inbreeding depression. In sum, our results suggest that a taxon's current mating system is more important than ploidy in influencing levels of inbreeding depression in natural populations of these annual plants.     

蜘蛛抱蛋属（百合科）二新种

报道了在广西发现的2个百合科蜘蛛抱蛋属Aspidistra新种,即乳突蜘蛛抱蛋A. papillata G. Z. Li和环江蜘蛛抱蛋A. huanjiangensis G. Z. Li&Y. G. Wei。乳突蜘蛛抱蛋与大花蜘蛛抱蛋A. tonkinensis（Gagner. ）F. T. Wang&K. Y. Lang近缘。它们的共同特征是:花单生;花被裂片两侧彼此覆盖;柱头盾状,边缘3裂,上表面具3条辐射状沟缝。不同点是:乳突蜘蛛抱蛋植株较大花蜘蛛抱蛋的粗大;叶柄较粗;叶片椭圆形或长椭圆形;花被阔钟