Friedrich Ehrendorfer

Polyploidy and Distribution

Since Polyploidy has been recognized as a widespread and common phenomenon among eukaryotes, particularly higher plants, biologists have been interested in possible causal connections between Polyploidy and distribution, and have tried to present relevant generalizations and “rules.” A quick historical survey of this topic takes us back to the first relevant studies on angiosperms during the thirties: Hagerup (1) and Tischler (2) demonstrated a frequency increase of polyploids from southern to northern latitudes and interpreted it as the result of greater hardiness of polyploids under extreme ecological conditions. Manton (3), on the basis of her studies on Biscutella in glaciated and unglaciated areas in Europe, was the first to stress the better colonizing potential of polyploids. The further elaboration of this question in the forties and fifties can be exemplified by contributions from A. and D. Love (4,5), Stebbins (6,7), and many others. During the same time studies concerned with Polyploidy and distribution were extended to some animal and other plant groups (cf. contributions in this Conference), foremost to the pteridophytes, again by Manton (8). Her finding of very high chromosome base numbers in many fern plants paved the way to our understanding of paleoPolyploidy, a phenomenon to which publications by Favarger (9) and S. and G. Mangenot (10) have further contributed during the sixties.

Phylogeny ofRubiaceae-Rubieae inferred from the sequence of a cpDNA intergene region

A phylogenetic analysis of 25 species, representing eight genera of theRubieae tribe (Rubiaceae), has been made using the DNA sequence of the chloroplastatp B-rbc L intergene region. Six tropical genera from other tribes ofRubiaceae have been used as outgroups. Whatever the method of analysis (distance, parsimony or maximum likelihood), five groups are clearly separated and described as informal clades. Their relative relationships are not clearly resolved by the parsimony analysis, resulting in eight equally parsimonious trees, 327 steps long, with a consistency index (CI) of 0.749 (excluding uninformative sites). TheRubieae tribe appears monophyletic from the data available. Some new and partly unexpected phylogenetic relationships are suggested. The genusRubia forms a separate clade and appears to be the relatively advanced sister group of the remaining taxa. TheSherardia clade also includes the generaCrucianella andPhuopsis. Galium sect.Aparinoides appears closely attached to theAsperula sect.Glabella clade. The remaining taxa ofGalium are paraphyletic:Galium sect.Platygalium (in theCruciata clade) is linked to the advanced generaCruciata andValantia; the more apomorphic groups ofGalium form theGalium sect.Galium clade, including the perennial sectionsGalium, Leiogalium, andLeptogalium as well as the annual (and possibly polyphyletic) sect.Kolgyda.

Chemosystematics of theRutaceae: Suggestions for a more natural taxonomy and evolutionary interpretation of the family

The chemosystematics ofRutaceae is reviewed on the basis of updated surveys of various secondary metabolites and their biosynthetic derivation. A comparison of these data with the morphological and geographical differentiation clearly shows that the current taxonomic arrangement of the family is to a large extent artificial and needs improvement. Starting from obviously “natural” groups of genera (or single genera) as “basic taxonomic entities” a new system with informal tribal names is suggested. In particular, the subfamilyToddalioideae is broken up altogether and its former members are rearranged among several of the 17 provisional tribes within the subfamilyRutoideae s. lat. Phylogenetic progressions can be recognized from parallel changes of morphological characters and biosynthetic pathways to secondary metabolites. As a general trend, a stepwise replacement of benzylisoquinolines by simple and complex anthranilic acid derived alkaloids, and eventually by coumarins and/or limonoids is confirmed. The available data are summarized in a discussion of the possible evolutionary relationships among theRutaceae, with theZanthoxylum- andEvodia-tribes in a central position.

Giemsa banded karyotypes, systematics, and evolution inAnacyclus (Asteraceae-Anthemideae)

Giemsa C-banding allows the differentiation of six, otherwise very similar karyotypes from the small genusAnacyclus. “Banding style”—with stable centromeric and nucleolar bands, and diverse specific banding patterns in distal chromosome segments—contributes significantly to generic demarcation and systematic grouping. The amount of banding corresponds to heterochromatic chromocentres and increases from perennials to annuals. Relationships with other nucleotype parameters and evolutionary mechanisms are discussed.

Phylogeny and systematics of Achillea (Asteraceae-Anthemideae) inferred from nrITS and plastid trnL-F DNA sequences

The N Hemisphere genus Achillea includes about 130 perennial and allogamous species, is centered in SE Europe/SW Asia, and exhibits a complex phyletic structure due to excessive hybridization and polyploidy. About half ofthe species and five of the six traditional sections together with several outgroup genera were studied using nrITS and plastid trnL-F DNA sequences. In spite of some discordance, these markers were shown by Maximum Parsimony and Bayesian Inference to be suitable for revealing relationships with generic allies and for distinguishing the main lineages within Achillea. With the inclusion of Otanthus (and possibly Leucocyclus) Achillea s.1. becomes monophyletic and appears as sister to Anacyclus. A basal clade is formed by the xerophytes of Achillea sections Babounya and Santolinoideae in SW Asia together with the Mediterranean coastal Otanthus. Achillea sect. Ptarmica s.l. has to be divided into the meso- to hygrophytic herbs of A. sect. Ptarmica s.s. in the N Hemisphere and the mountain species of A. sect. Anthemoideae. The latter differentiated in the mountains from NW Anatolia to the Pyrenees, possibly originating from ancestors related to the extant A. ligustica. Finally, taxa of sect. Achillea s.l. (to be merged with A. sect. Filipendulinae) radiated from a center in SE Europe, occupied very different open habitats, and reached an extensive distribution with the very polymorphic polyploid and reticulate complex A. millefolium agg. Here and in other groups of Achillea, various instances of conflicting evidence from nrITS, plastid trnL-F, and morphology point to hybridization and lineage sorting. This means that reticulate evolution is not only involved in recent radiations but must have been active already in the early diversification of the genus.

Fluorescent chromosome banding in the cultivated species ofCapsicum (Solanaceae)

Fluorochrome chromosome banding is applied for the first time to 15 samples of five cultivatedCapsicum species, all with 2n = 24, and allows a detailed analysis of the karyotypes (Tables 2–3, Fig. 8). Banding patterns differ between cytotypes, species and groups, reflecting the dynamics of chromosomal differentiation and evolutionary divergence. Taxa have from 1 to 4 NOR-bearing satellited chromosome pairs and exhibit increasing numbers of terminal (rarely intercalary and indistinct centromeric) heterochromatic fluorescent bands. Amounts of heterochromatin (expressed in % of karyotype length) increase from the group withC. annuum (1.80–2.88),C. chinense (3.91–5.52), andC. frutescens (5.55) toC. baccatum (7.30–7.56), and finally toC. pubescens (18.95). In all taxa CMA+DAPI—(GC-rich) constitutive heterochromatin dominates, onlyC. pubescens has an additional CMAo DAPI+ (AT-rich) band. The fluorochrome bands generally (but not completely) correspond to the Giemsa C-bands. Structural heterozygosity can be demonstrated but is not prominent. The independent origin of at least three evolutionary lines leading to the cultivated taxa ofCapsicum is supported.

DNA content, heterochromatin, mitotic index, and growth in perennial and annualAnthemidea (Asteraceae)

Within 18 perennial and annualAnthemideae species from 7 genera nuclear volume, DNA content and karyogram length are positively correlated. Annuals develop much more rapidly than related perennials. This is obviously due to greater cell elongation and abbreviated cell cycles. Annuals have lower or much higher DNA content and usually more heterchromatin than related perennials. Possible direct influences of nuclear on developmental parameters, and different evolutionary strategies in annuals and perennials are discussed.

Reproductive biology in the primitive relic AngiospermDrimys brasiliensis (Winteraceae)

From field observations onDrimys brasiliensis, principally in the Botucatu region of São Paulo State, Brazil, new data on the reproductive biology, the rhythm of growth, and the development of lateral cymose inflorescences, flowers and fruits are presented. Pollination accelerates the rate of flower-development for about 4–6 days. Pollination experiments show thatD. brasiliensis is not self-sterile; because of mechanical devices the sticky pollen grains do not normally come into contact with the stigmata unless an animal pollen vector is involved. The pollinators are diurnalColeoptera, Diptera andThysanoptera which eat from the pollen, lick from the stigmatic exudates and (in case of the flies) probably also from the staminal glands. Fruit- and seedeaters are birds which seem to be the main dispersal agents. Establishment of new individuals normally is through seedlings, but also by vegetative propagation through plagiotropous branches which may root and separate from the mother plant. The morphological, developmental and reproductive aspects inD. brasiliensis are discussed in a wider context, compared with data from otherMagnoliidae, and related to aspects of early Angiosperm evolution.

Closing remarks: Systematics and evolution of centrospermous families

The present circumscription ofCentrospermae, including the “central position” of the closely relatedMolluginaceae-Aizoaceae-Phytolaccaceae, and the divergence of the other centrospermous families are discussed. The group appears to be monophyletic and may have been derived from “Polycarpicae” (reminiscent ofIlliciales?). Flower reduction, a trend towards anemophily, and loss of anthocyanin pigments appear significant for primitiveCentrospermae. Development of showy flowers, secondary polyandry and betalain pigments characterize later evolutionary stages towards zoophily (e.g.Portulacaceae, Cactaceae). Further reductions are again connected with anemophily (e.g.Achatocarpaceae, Chenopodiaceae).

Giemsa C-banded karyotypes inCapsicum (Solanaceae)

Giemsa C-banding is applied for the first time inCapsicum, allowing preliminary karyotype differentiation of six diploid species. Comparison of interphase nuclei and heterochromatic C-bands reveals striking differences between taxa and contributes to their taxonomic grouping. Therefore, C-banding appears to be a powerful tool for the cytogenetics and karyosystematics of the genus. Banding patterns are characterized by the omnipresence of centromeric bands and a variable number of smaller to larger distal bands, with the addition of intercalary bands in some cases. Satellites are always C-positive. Relationships between species and possible trends of karyotype evolution are discussed, with special reference to the origin of x = 13 from x = 12 and the increase of heterochromatin, regarded as advanced features.