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Susanne S. Renner - One of the best experts on this subject based on the ideXlab platform.
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Repeated evolution of dioecy from monoecy in Siparunaceae (Laurales). Systematic Biology 50: 700–712
2015Co-Authors: Susanne S. Renner, Hyosig WonAbstract:Abstract.—Siparunaceae comprise Glossocalyx with one species in West Africa and Siparuna with 65 species in the neotropics; all have unisexual owers, and 15 species are monoecious, 50 dioecious. Parsimony and maximum likelihood analyses of combined nuclear ribosomal ITS and chloroplast trnL-trnF intergenic spacer sequences yielded almost identical topologies, which were used to trace the evolution of the two sexual systems. The African species, which is dioecious, was sister to all neotropical species, and the monoecious species formed a grade basal to a large dioecious Andean clade. Dioecy evolved a second time within the monoecious grade. Geographical mapping of 6,496 herbarium collections from all species sorted by sexual system showed that monoecy is conned to low-lying areas (altitude< 700m) in the Amazon basin and southern Central America. The onlymor-phological trait with a strong phylogenetic signal is leaf margin shape (entire or toothed), although this character also correlates with altitude, probably reecting selection on leaf shapes by temperature and rainfall regimes. The data do not reject the molecular clock, and branch lengths suggest that the shift to dioecy in the lowlands occurred many million years after the shift to dioecy in the ancestor of the Andean clade. [Altitudinal distribution of sexual systems; dioecy; molecular clock; monoecy; sexual system evolution.
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Vol. 1/1, pp. 61–77 © Gustav Fischer Verlag, 1998 Phylogenetic affinities of Monimiaceae based on cpDNA gene and spacer sequences
2015Co-Authors: Susanne S. RennerAbstract:Nucleotide sequence data from the chloroplast rbcL gene and the trnL-trnF intergenic spacer of 58 species in 38 genera were used to infer the phylogenetic affinities of Monimiaceae to other Laurales, and to assess whether the family in the traditional wide sense is monophyletic. Besides Monimiaceae, the Laurales comprise Calycan-thaceae, Gomortegaceae, Hernandiaceae, and Lauraceae. Magnoliaceae and Myris-ticaceae were used as outgroups. Based on recent molecular data, Amborellaceae and Chloranthaceae, which have sometimes been included in the order, do not be-long in the Laurales, and indeed trnL-trnF sequences of Amborella (Amborellaceae) and Hedyosmum (Chloranthaceae) were too different to be unambiguously aligned with the remaining sequences. Parsimony analyses of the trnL-trnF and trnL-trnF-rbcL data groups the genera into five major clades, Calycanthaceae, Atherosperma-taceae, Gomortega, Siparunaceae, and a weakly supported Monimiaceae s.str.-Lau-raceae-Hernandiaceae clade. RbcL data alone provide no resolution at the family level. Many aspects of traditional intra-familiar classification of Monimiaceae are sup
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Repeated Evolution of Dioecy from Monoecy in Siparunaceae (Laurales)
2014Co-Authors: Susanne S. Renner, Hyosig WonAbstract:Abstract.—Siparunaceae comprise Glossocalyx with one species in West Africa and Siparuna with 65 species in the neotropics; all have unisexual owers, and 15 species are monoecious, 50 dioecious. Parsimony and maximum likelihood analyses of combined nuclear ribosomal ITS and chloroplast trnL-trnF intergenic spacer sequences yielded almost identical topologies, which were used to trace the evolution of the two sexual systems. The African species, which is dioecious, was sister to all neotropical species, and the monoecious species formed a grade basal to a large dioecious Andean clade. Dioecy evolved a second time within the monoecious grade. Geographical mapping of 6,496 herbarium collections from all species sorted by sexual system showed that monoecy is conned to low-lying areas (altitude < 700m) in the Amazon basin and southern Central America. The only mor-phological trait with a strong phylogenetic signal is leaf margin shape (entire or toothed), although this character also correlates with altitude, probably reecting selection on leaf shapes by temperature and rainfall regimes. The data do not reject the molecular clock, and branch lengths suggest that the shift to dioecy in the lowlands occurred many million years after the shift to dioecy in the ancestor of the Andean clade. [Altitudinal distribution of sexual systems; dioecy; molecular clock; monoecy; sexual system evolution.
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trans atlantic trans pacific and trans indian ocean dispersal in the small gondwanan Laurales family hernandiaceae
Journal of Biogeography, 2010Co-Authors: Ingo Michalak, Libing Zhang, Susanne S. RennerAbstract:Aim To investigate the historical biogeography of the pantropical flowering plant family Hernandiaceae (Laurales), which today comprises 62 species in five genera. Location Hernandiaceae occur in Africa (9 species), Madagascar (4), the Neotropics (25), Australia (3), southern China, Indochina, Malesia, and on numerous Pacific Islands (32). These numbers include two widespread species, Hernandia nymphaeifolia, which ranges from East Africa to the Ogasawara Islands and New Caledonia, and Gyrocarpus americanus, thought to have a pantropical range. Methods We sampled 37 species from all genera, the widespread ones with multiple accessions, for a chloroplast DNA matrix of 2210 aligned nucleotides, and used maximum likelihood to infer species relationships. Divergence time estimation relied on an uncorrelated-rates relaxed molecular clock calibrated with outgroup fossils of Lauraceae and Monimiaceae. Results The deepest split in the family is between a predominantly African-Madagascan-Malesian lineage comprising Hazomalania, Hernandia and Illigera, and an African-Neotropical lineage comprising Gyrocarpus and Sparattanthelium; this split may be 122 (110-134) Myr old. The stem lineages of the five genera date back at least to the Palaeocene, but six splits associated with transoceanic range disjunctions date only to the Oligocene and Miocene, implying long-distance dispersal. It is inferred that Hernandia beninensis reached the West African islands of Sao Tome and Bioko from the West Indies or the Guianas; Hernandia dispersed across the Pacific; and Illigera madagascariensis reached Madagascar from across the Indian Ocean. Main conclusions The disjunct ranges and divergence times of sister clades in the Hernandiaceae are partly congruent with the break-up of West Gondwana, but mostly with later transoceanic dispersal. An exceptional ability to establish following prolonged oceanic dispersal may be largely responsible for the evolutionary persistence of this small clade.
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biogeography of the monimiaceae Laurales a role for east gondwana and long distance dispersal but not west gondwana
Journal of Biogeography, 2010Co-Authors: Susanne S. Renner, Joeri S Strijk, Dominique Strasberg, Christophe ThebaudAbstract:Aim The biogeography of the tropical plant family Monimiaceae has long been thought to reflect the break-up of West and East Gondwana, followed by limited transoceanic dispersal. Location Southern Hemisphere, with fossils in East and West Gondwana. Methods We use phylogenetic analysis of DNA sequences from 67 of the c. 200 species, representing 26 of the 28 genera of Monimiaceae, and a Bayesian relaxed clock model with fossil prior constraints to estimate species relationships and divergence times. Likelihood optimization is used to infer switches between biogeographical regions on the highest likelihood tree. Results Peumus from Chile, Monimia from the Mascarenes and Palmeria from eastern Australia/New Guinea form a clade that is sister to all other Monimiaceae. The next-deepest split is between the Sri Lankan Hortonia and the remaining genera. The African Monimiaceae, Xymalos monospora, then forms the sister clade to a polytomy of five clades: (I) Mollinedia and allies from South America; (II) Tambourissa and allies from Madagascar and the Mascarenes; (III) Hedycarya, Kibariopsis and Leviera from New Zealand, New Caledonia and Australia; (IV) Wilkiea, Kibara, Kairoa; and (V) Steganthera and allies, all from tropical Australasia. Main conclusions Tree topology, fossils, inferred divergence times and ances-tral area reconstruction fit with the break-up of East Gondwana having left a still discernible signature consisting of sister clades in Chile and Australia. There is no support for previous hypotheses that the break-up of West Gondwana (Africa/South America) explains disjunctions in the Monimiaceae. The South American Mollinedia clade is only 28–16 Myr old, and appears to have arrived via trans-Pacific dispersal from Australasia. The clade apparently spread in southern South America prior to the Andean orogeny, fitting with its first-diverging lineage (Hennecartia) having a southern-temperate range. The crown ages of the other major clades (II–V) range from 20 to 29 Ma, implying over-water dispersal between Australia, New Caledonia, New Zealand, and across the Indian Ocean to Madagascar and the Mascarenes. The endemic genus Monimia on the Mascarenes provides an interesting example of an island lineage being much older than the islands on which it presently occurs.
Yukitoshi Kimoto - One of the best experts on this subject based on the ideXlab platform.
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embryology of hortonioideae and monimioideae monimiaceae Laurales characteristics of the lower monimioids
Botanical Journal of the Linnean Society, 2008Co-Authors: Yukitoshi Kimoto, Hiroshi TobeAbstract:We investigated the embryology of the ‘lower’ monimioids, i.e. Monimioideae (Monimia, Palmeria and Peumus) and Hortonioideae (Hortonia), which are poorly described embryologically. Our results show that, contrary to what has been reported in the literature, ‘lower’ monimioids show very little variation in their embryological characters. Comparisons with Mollinedioideae (a large derived subfamily in Monimiaceae) and other families in Laurales show that the ‘lower’ monimioids are relatively consistent in sharing predominantly isobilateral tetrads of microspores and megaspores, a non-specialized chalaza, and a mesotestal–endotestal seed coat (with tracheoidal cells of the meso- and endotesta). It is likely that, while the shared successive cytokinesis during meiosis of microspore mother cells supports the Monimiaceae–Hernandiaceae–Lauraceae clade obtained by molecular evidence, no synapomorphies exist to support a sister-group relationship of Monimiaceae with Hernandiaceae or Lauraceae. Instead, the lack of hypostase in ovules and/or young seeds, the lack of endosperm in mature seeds and the amoeboid tapetum in the anther are likely synapomorphies of Hernandiaceae and Lauraceae. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 228–241.
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embryology of illigera and sparattanthelium hernandiaceae Laurales family characteristics and relationships
International Journal of Plant Sciences, 2008Co-Authors: Yukitoshi Kimoto, Hiroshi TobeAbstract:The Hernandiaceae, a small family comprising five genera that are closely related to the Lauraceae and Monimiaceae, exhibit highly diverse morphological characters. Here, we present the first embryological study of Illigera and Sparattanthelium and, by comparing those data to those from Gyrocarpus and Hernandia, discuss the relationships in the Hernandiaceae and related families. Our embryological data indicate that the Hernandiaceae, which are characterized by a multiplicative outer integument, share several features (apomorphies) with the Lauraceae, including an amoeboid tapetum, a lack of hypostase, and exalbuminous seeds, suggesting a close relationship between them. Within the Hernandiaceae, Hernandia/Illigera (Hernandioideae) exhibit radially elongated tapetal cells in the anthers, monolayered pollen mother cells, anthers dehisced by laterally hinged valves, thick parietal tissue in the nucellus, a nucellar beak, a vascularized outer integument or testa, and a thick, persistent mesotesta. In compari...
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embryology of gomortegaceae Laurales characteristics and character evolution
Journal of Plant Research, 2003Co-Authors: Yukitoshi Kimoto, Hiroshi TobeAbstract:Embryological characters of Siparunaceae, which are poorly understood, were studied on the basis of two constituent genera, an African Glossocalyx and a South American Siparuna, to better understand their evolution within Laurales. These two genera have many embryological characteristics in common with the other lauralean families. Noticeably, they share the multi-celled ovule archesporium (uncertain in Glossocalyx) as a synapomorphy with all the other lauralean families except Lauraceae, the anthers dehisced by valves as a synspomorphy with all the other lauralean families except Calycanthaceae and Monimiaceae, and the bisporangiate anther as a synapomorphy with Gomortegaceae and Atherospermataceae. Siparunaceae are, however, distinct from all other laularean families in having unitegmic ovules that were derived from bitegmic ovules, probably due to an elimination of the outer integument. Likewise, the lack of the testa (i.e., developed outer integument), the "endotegmic" seed coat, and the perichalazal seed at maturity are also characteristics of Siparunaceae. Within the family, Siparuna differs from Glossocalyx in having plural tetrads of megaspores and plural, starchy-rich, one-nucleate, tubular embryo sacs (autapomorphies). On the other hand, Glossocalyx is characterized by having bilaterally flattened seeds (autapomorphy). Although functional aspects of those autapomorphies are uncertain, both Glossocalyx and Siparuna show evolution in different embryological characters.
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Embryology of Laurales: a Review and Perspectives
Journal of Plant Research, 2001Co-Authors: Yukitoshi Kimoto, Hiroshi TobeAbstract:and Siparunaceae) are probably defined by a multi-celled ovule archesporium and a crushed mesotesta. Within Laurales, 16 embryological characters are found to be diversified, including the number of microsporangia (four or two), mode of anther dehiscence (by slits or valves), the number of archesporial cells in an ovule (one, two or more), and so on. Their respective evolutions were traced on a phylogenetic tree generated from molecular and morphological data, supporting that Calycanthaceae represent the earliest branch and are sister to a clade comprising six remaining families with a valvate anther dehiscence as already suggested. However, because of a lack of sufficient data from each family of Laurales, embryological characters often have alternative possibilities with respect to where they have evolved. More extensive and/or intensive studies of individual families are needed to clarify their exact evolutionary relationships.
Jorge S Parra - One of the best experts on this subject based on the ideXlab platform.
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determinacion de indices de vulnerabilidad y mesomorfia en especies de Laurales de la selva san eusebio merida venezuela
Revista Pittieria, 2010Co-Authors: Jorge S ParraAbstract:En el presente trabajo se determinaron los indices vulnerabilidad (IV) y mesomorfia (IM) de la madera de siete especies nativas del orden Laurales: seis especies de Lauraceae (Aniba robusta, Beilschmiedia latifolia, Cinnamomum triplinerve, Nectandra laurel, Ocotea floribunda, O. macropoda) y una Chloranthaceae (Hedyosmum racemosum), que crecen en de la Estacion Experimental San Eusebio, estado Merida, Venezuela. Se tomaron muestras a 1,30 m (altura de pecho), elaborando laminas y macerados, segun la metodologia aplicada en el Laboratorio de Anatomia de Maderas de la Facultad de Ciencias Forestales y Ambientales (ULA). Se encontro una tendencia en estas maderas a tener poros con diametro mediano, baja frecuencia, longitud de los elementos de los vasos mediamente largos, punteaduras intervasculares de grandes a medianas, platinas de perforacion predominantemente simples en los taxones de Lauraceae y escalariformes con mas de 40 barras y elementos de los vasos muy largos en Hedyosmum racemosum. Las siete especies correspondieron a maderas mesomorficas, siendo eficientes en la conductancia hidraulica, pero vulnerables a la embolia.
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determinacion de indices de vulnerabilidad y mesomorfia en especies de Laurales de la selva san eusebio merida venezuela vulnerability and mesomorphy indexes determination for Laurales from san eusebio forest merida venezuela
2010Co-Authors: Jorge S ParraAbstract:The vulnerability and mesomorphy index of seven native species of Laurales: six of Lauraceae (Aniba robusta, Beilschmiedia latifolia, Cinnamomum triplinerve, Nectandra laurel, Ocotea floribunda, O. macropoda ) and one of Chloranthaceae (Hedyosmum racemosum) were determined. The wood samples were taken at 1,30 m (breast height) from trees growing in San Eusebio experimental station, Merida state, Venezuela. An anatomical study of wood tissues was performed, additionally maceration was performed to analyze vessel elements. The technique used was the standard at the wood anatomy laboratory at Facultad de Ciencias Forestales y Ambientales (Forestry and Environmental Sciences School, ULA). The woods have low frequency pores with medium diameter and vessel elements with moderate length. In the Lauraceae, the woods have from large to medium size intervessel pits, predominantly with simple perforation plates. Hedyosmum racemosum showed scalariform plates with more than 40 bars and elements in the vessels that are long. The seven species studied showed mesomorphic wood, highly efficient for water conductance, but they are vulnerable to suffer embolism.
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anatomia del leno e identificacion de siete especies de Laurales en san eusebio merida venezuela
Revista Pittieria, 2009Co-Authors: Jorge S ParraAbstract:En este trabajo se describe la anatomia de la madera de siete especies del orden Laurales, seis de Lauraceae (Aniba robusta, Beilschmiedia latifolia, Cinnamomum triplinerve, Nectandra laurel, Ocotea floribunda y O. macropoda) y una Chloranthaceae (Hedyosmum racemosum) de la selva nublada San Eusebio, estado Merida. Para esto se prepararon laminas con las muestras de madera. Para conocer las variaciones individuales dentro de una especie se realizo un analisis de varianza y la prueba de Duncan. Los resultados muestran que el leno de las especies de Lauraceae es muy uniforme, se diferencian principalmente en la presencia o ausencias de septos en las fibras, como de celulas oleiferas y parenquima marginal. En la anatomia de la madera de Hedyosmum racemosum llama la atencion las barras multiples en las placas de perforacion, en cambio en los taxones de Lauraceae predominan las placas de perforacion simples, ocasionalmente multiples de pocas barras. Se elaboro una clave para determinar las especies, basada en las caracteristicas del leno
Peter K Endress - One of the best experts on this subject based on the ideXlab platform.
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inflorescence structure in Laurales stable and flexible patterns
International Journal of Plant Sciences, 2020Co-Authors: Peter K Endress, David H LorenceAbstract:Premise of research. This is the first comparative study of inflorescence morphology through all seven families of the order Laurales (Atherospermataceae, Calycanthaceae, Gomortegaceae, Hernandiace...
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fruit structure of calycanthaceae Laurales histology and development
International Journal of Plant Sciences, 2018Co-Authors: Mikhail S Romanov, Peter K Endress, Alexey Ch V F Bobrov, Anton A Yurmanov, Ekaterina S RomanovaAbstract:Premise of research. Fruit structure, in contrast to flower structure, has not been the subject of detailed comparative studies in many angiosperm lineages. This study focuses on fruit morphology, ...
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The evolution of floral biology in basal angiosperms
Philosophical transactions of the Royal Society of London. Series B Biological sciences, 2010Co-Authors: Peter K EndressAbstract:In basal angiosperms (including ANITA grade, magnoliids, Choranthaceae, Ceratophyllaceae) almost all bisexual flowers are dichogamous (with male and female functions more or less separated in time), and nearly 100 per cent of those are protogynous (with female function before male function). Movements of floral parts and differential early abscission of stamens in the male phase are variously associated with protogyny. Evolution of synchronous dichogamy based on the day/night rhythm and anthesis lasting 2 days is common. In a few clades in Magnoliales and Laurales heterodichogamy has also evolved. Beetles, flies and thrips are the major pollinators, with various degrees of specialization up to large beetles and special flies in some large-flowered Nymphaeaceae, Magnoliaceae, Annonaceae and Aristolochiaceae. Unusual structural specializations are involved in floral biological adaptations (calyptras, inner staminodes, synandria and food bodies, and secretory structures on tepals, stamens and staminodes). Numerous specializations that are common in monocots and eudicots are absent in basal angiosperms. Several families are poorly known in their floral biology.
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integrating early cretaceous fossils into the phylogeny of living angiosperms magnoliidae and eudicots
Journal of Systematics and Evolution, 2010Co-Authors: James A. Doyle, Peter K EndressAbstract:Abstract Over the past 25 years, discoveries of Early Cretaceous fossil flowers, often associated with pollen and sometimes with vegetative parts, have revolutionized our understanding of the morphology and diversity of early angiosperms. However, few of these fossils have been integrated into the increasingly robust phylogeny of living angiosperms based primarily on molecular data. To remedy this situation, we have used a morphological dataset for living basal angiosperms (including basal eudicots and monocots) to assess the most parsimonious positions of early angiosperm fossils on cladograms of Recent plants, using constraint trees that represent the current range of hypotheses on higher-level relationships, and concentrating on Magnoliidae (the clade including Magnoliales, Laurales, Canellales, and Piperales) and eudicots. In magnoliids, our results confirm proposed relationships of Archaeanthus (latest Albian?) to Magnoliaceae, Endressinia (late Aptian) to Magnoliales (the clade comprising Degeneria, Galbulimima, Eupomatia, and Annonaceae), and Walkeripollis pollen tetrads (late Barremian?) to Winteraceae, but they indicate that Mauldinia (early Cenomanian) was sister to both Lauraceae and Hernandiaceae rather than to Lauraceae alone. Among middle Albian to early Cenomanian eudicots, we confirm relationships of Nelumbites to Nelumbo, platanoid inflorescences and Sapindopsis to Platanaceae, and Spanomera to Buxaceae. With the possible exception of Archaeanthus, these fossils are apparently not crown group members of living families but rather stem relatives of one or more families.
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Comparative Gynoecium Structure and Development in Calycanthaceae (Laurales)
International Journal of Plant Sciences, 2009Co-Authors: Yannick M. Staedler, Peter H Weston, Peter K EndressAbstract:Calycanthaceae, sister to all other Laurales, are the most distinct family of the order in their gynoecium structure (lateral placentation, presence of two ovules). Gynoecium structure was studied in a representative of each genus of Calycanthaceae and gynoecium development in a representative of each of the two subfamilies (Calycanthoideae and Idiospermoideae). Newly found shared features are postgenital coherence between the free carpels (extragynoecial compitum), abortion of the upper of the two ovules, and lobation of the outer integument. Differences in reproductive structures between the two subfamilies are reviewed. Newly found differences include carpel primordium shape, contribution of the outer integument to micropyle formation, epidermis differentiation of the rim of the integuments, and mode of formation of the compitum. Unexpectedly, at anthesis, ovary and ovules of Idiospermum are not larger than those of Calycanthoideae, despite the conspicuous difference in fruit. The identity of “staminod...
Hiroshi Tobe - One of the best experts on this subject based on the ideXlab platform.
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embryology of hortonioideae and monimioideae monimiaceae Laurales characteristics of the lower monimioids
Botanical Journal of the Linnean Society, 2008Co-Authors: Yukitoshi Kimoto, Hiroshi TobeAbstract:We investigated the embryology of the ‘lower’ monimioids, i.e. Monimioideae (Monimia, Palmeria and Peumus) and Hortonioideae (Hortonia), which are poorly described embryologically. Our results show that, contrary to what has been reported in the literature, ‘lower’ monimioids show very little variation in their embryological characters. Comparisons with Mollinedioideae (a large derived subfamily in Monimiaceae) and other families in Laurales show that the ‘lower’ monimioids are relatively consistent in sharing predominantly isobilateral tetrads of microspores and megaspores, a non-specialized chalaza, and a mesotestal–endotestal seed coat (with tracheoidal cells of the meso- and endotesta). It is likely that, while the shared successive cytokinesis during meiosis of microspore mother cells supports the Monimiaceae–Hernandiaceae–Lauraceae clade obtained by molecular evidence, no synapomorphies exist to support a sister-group relationship of Monimiaceae with Hernandiaceae or Lauraceae. Instead, the lack of hypostase in ovules and/or young seeds, the lack of endosperm in mature seeds and the amoeboid tapetum in the anther are likely synapomorphies of Hernandiaceae and Lauraceae. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 228–241.
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embryology of illigera and sparattanthelium hernandiaceae Laurales family characteristics and relationships
International Journal of Plant Sciences, 2008Co-Authors: Yukitoshi Kimoto, Hiroshi TobeAbstract:The Hernandiaceae, a small family comprising five genera that are closely related to the Lauraceae and Monimiaceae, exhibit highly diverse morphological characters. Here, we present the first embryological study of Illigera and Sparattanthelium and, by comparing those data to those from Gyrocarpus and Hernandia, discuss the relationships in the Hernandiaceae and related families. Our embryological data indicate that the Hernandiaceae, which are characterized by a multiplicative outer integument, share several features (apomorphies) with the Lauraceae, including an amoeboid tapetum, a lack of hypostase, and exalbuminous seeds, suggesting a close relationship between them. Within the Hernandiaceae, Hernandia/Illigera (Hernandioideae) exhibit radially elongated tapetal cells in the anthers, monolayered pollen mother cells, anthers dehisced by laterally hinged valves, thick parietal tissue in the nucellus, a nucellar beak, a vascularized outer integument or testa, and a thick, persistent mesotesta. In compari...
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Chromosome evolution in the Laurales based on analyses of original and published data
Journal of Plant Research, 2006Co-Authors: Kazuo Oginuma, Hiroshi TobeAbstract:We present a summary of currently available chromosome information for all seven families in the order Laurales on the basis of original and previously published data and discuss the evolution of chromosomes in this order. Based on a total of 53 genera for which chromosome data were available, basic chromosome numbers appear consistent within families: x = 11 (Calycanthaceae); x = 22 (Atherospermataceae and Siparunaceae); x = 19 (Monimiaceae); and x = 12 and 15 (Lauraceae). The Hernandiaceae have diverse numbers: x = 15 (Gyrocarpoideae) and x = 18 and 20 (Hernandioideae). Karyotype analyses showed that Hennecartia , Kibaropsis , and Matthaea (all Monimiaceae) contained two or three sets of four distinct chromosomes in 38 somatic chromosomes, suggesting that 2 n = 38 was derived by aneuploid reduction from 2 n = 40, a tetraploid of x = 10. In light of the overall framework of phylogenetic relationships in the Laurales, we show that x = 11 is an archaic base number in the order and is retained in the Calycanthaceae, which are sister to the remainder of the order. Polyploidization appears to have occurred from x = 11 to x = 22 in a common clade of the Siparunaceae, Atherospermataceae, and Gomortegaceae (although 2 n = 42 in the Gomortegaceae), and aneuploid reduction from x = 11 to x = 10 occurred in a common clade of the Hernandiaceae, Lauraceae, and Monimiaceae. To understand chromosome evolution in the Lauraceae, however, more studies are needed of genera and species of Cryptocaryeae.
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embryology of gomortegaceae Laurales characteristics and character evolution
Journal of Plant Research, 2003Co-Authors: Yukitoshi Kimoto, Hiroshi TobeAbstract:Embryological characters of Siparunaceae, which are poorly understood, were studied on the basis of two constituent genera, an African Glossocalyx and a South American Siparuna, to better understand their evolution within Laurales. These two genera have many embryological characteristics in common with the other lauralean families. Noticeably, they share the multi-celled ovule archesporium (uncertain in Glossocalyx) as a synapomorphy with all the other lauralean families except Lauraceae, the anthers dehisced by valves as a synspomorphy with all the other lauralean families except Calycanthaceae and Monimiaceae, and the bisporangiate anther as a synapomorphy with Gomortegaceae and Atherospermataceae. Siparunaceae are, however, distinct from all other laularean families in having unitegmic ovules that were derived from bitegmic ovules, probably due to an elimination of the outer integument. Likewise, the lack of the testa (i.e., developed outer integument), the "endotegmic" seed coat, and the perichalazal seed at maturity are also characteristics of Siparunaceae. Within the family, Siparuna differs from Glossocalyx in having plural tetrads of megaspores and plural, starchy-rich, one-nucleate, tubular embryo sacs (autapomorphies). On the other hand, Glossocalyx is characterized by having bilaterally flattened seeds (autapomorphy). Although functional aspects of those autapomorphies are uncertain, both Glossocalyx and Siparuna show evolution in different embryological characters.
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Embryology of Laurales: a Review and Perspectives
Journal of Plant Research, 2001Co-Authors: Yukitoshi Kimoto, Hiroshi TobeAbstract:and Siparunaceae) are probably defined by a multi-celled ovule archesporium and a crushed mesotesta. Within Laurales, 16 embryological characters are found to be diversified, including the number of microsporangia (four or two), mode of anther dehiscence (by slits or valves), the number of archesporial cells in an ovule (one, two or more), and so on. Their respective evolutions were traced on a phylogenetic tree generated from molecular and morphological data, supporting that Calycanthaceae represent the earliest branch and are sister to a clade comprising six remaining families with a valvate anther dehiscence as already suggested. However, because of a lack of sufficient data from each family of Laurales, embryological characters often have alternative possibilities with respect to where they have evolved. More extensive and/or intensive studies of individual families are needed to clarify their exact evolutionary relationships.