Chromosomal studies and evolution in Sapindaceae

Lombello, Ricardo A.; Forni‐Martins, Eliana Regina

doi:10.1080/00087114.1998.10589123

Cited by 28 publications

(28 citation statements)

References 8 publications

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“…Thus, a disploid species with smaller chromosome number can be derived in relation to another with more chromosomes, and an entire taxonomic group can speciate through disploidy. Lombello and Forni-Martins (1998) showed that the derivation of the climber habit from bushes and trees in Sapindaceae processed predominantly through decreasing disploidy. It is still necessary to consider that not always the speciation implies in numerical alteration of chromosomes, for species can differ through genetic or structural alterations of the chromosomes (Stebbins, 1971).…”

Section: Microsporogenesis and Sexual Reproductionmentioning

confidence: 99%

Chromosome studies on Brazilian cerrado plants

Forni‐Martins

Martins

2000

Genet. Mol. Biol.

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Cerrado is the Brazilian name for the neotropical savanna, which occurs mainly in Brazilian Central Plateau, composed of herbaceous-subshrubby and shrubby-arboreal floras, both of which are heliophilous, highly diverse and regionally differentiated. Considering species distribution and chromosome numbers, some authors have proposed that the herbaceous-subshrubby flora of the neotropical savanna is quite old, while the shrubby-arboreal flora is derived from forests, a hypothesis that implies higher chromosome numbers in the savanna than in the forest. If, however, chromosome numbers are similar in the cerrado and in forests, both could be similarly old, indicating that bi-directional flow of flora occurred in the past. This paper presents data on chromosome numbers and microsporogenesis for 20 species in 13 families collected in the States of São Paulo, Goiás and Minas Gerais, providing previously unpublished data for Myrcia (Myrtaceae), Luxemburgia (Ochnaceae) and Hortia (Rutaceae). Meiosis proved to be normal, indicating regularity in the sexual reproductive process. Chromosome numbers varied from 2n = 18 (Allamanda angustifolia: Apocynaceae) to 2n = ca. 104 (Ouratea spectabilis: Ochnaceae), being low (20 < 2n < 30) in most of the species. Since similar numbers have been observed with forest species, it is not, at the moment, possible to support the hypothesis that cerrado species derived from the surrounding forests. Instead, we suggest the possibility of a bi-directional exchange of floristic elements between cerrado and forests during evolutionary time.
Cerrado é a palavra que, no Brasil, designa a savana neotropical, com área nuclear no Planalto Central, constituída de uma flora herbáceo-subarbustiva e outra arbustivo-arbórea, ambas heliófilas, altamente diversificadas e regionalmente diferenciadas. Considerando a distribuição de espécies e de números cromossômicos, alguns autores propuseram que a flora herbáceo-subarbustiva da savanna neotropical seria bastante antiga, enquanto a flora arbustivo-arbórea seria derivada das florestas Atlântica e Amazônica, uma hipótese que implica na ocorrência de números cromossômicos mais altos no cerrado que nas florestas. Porém, se os números cromossômicos forem similares no cerrado e nas florestas, ambos os tipos de formação poderiam ser similarmente antigos, indicando que um fluxo florístico bidirecional entre o cerrado e as florestas teria ocorrido no passado. Este trabalho apresenta dados sobre números cromossômicos e microsporogênese de 20 espécies em 13 famílias, coletadas nos estados de São Paulo, Goiás e Minas Gerais, trazendo informações inéditas para Myrcia (Myrtaceae), Luxemburgia (Ochnaceae) e Hortia (Rutaceae). A meiose mostrou-se normal, indicando regularidade no processo reprodutivo sexual. Os números cromossômicos variaram de 2n = 18 (Allamanda angustifolia: Apocynaceae) a 2n = ca. 104 (Ouratea spectabilis: Ochnaceae), sendo baixos (20 < 2n < 30) na maioria das espécies. Como números cromossômicos similares têm sido encontrados também em espécies flores...

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Section: Microsporogenesis and Sexual Reproductionmentioning

confidence: 99%

Chromosome studies on Brazilian cerrado plants

Forni‐Martins

Martins

2000

Genet. Mol. Biol.

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“…These formulas were used for the first time in relative chromosome number frequency determination by Lombello & Forni-Martins (1998a) in their study on Sapindaceae.…”

Section: Methodsmentioning

confidence: 99%

“…Lombello & Forni-Martins (1998a) observed a relationship between the climbing habit and some trends in chromosome morphology in Sapindaceae. This pattern of karyotype derivation consisted of a decrease in chromosome number and an increase in chromosome size.…”

Section: Introductionmentioning

confidence: 99%

Malpighiaceae: correlations between habit, fruit type and basic chromosome number

Lombello

Forni‐Martins

2003

Acta Bot. Bras.

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-(Malpighiaceae: correlations between habit, fruit type and basic chromosome number). The family Malpighiaceae presents species with different habits, fruit types and cytological characters. Climbers are considered the most derived habit, followed, respectively, by the shrubby and arboreal ones. The present study examines the relationship between basic chromosome numbers and the derivation of climbing habit and fruit types in Malpighiaceae. A comparison of all the chromosome number reports for Malpighiaceae showed a predominance of chromosome numbers based on x=5 or 10 in the genera of sub-family Malpighioideae, mainly represented by climbers with winged fruits, whereas non-climbing species with non-winged fruits, which predominate in sub-family Byrsonimoideae, had counts based on x=6, which is considered the less derived basic number for the family. Based on such data, confirmed by statistic assays, and on the monophyletic origin of this family, we admit the hypothesis that morphological derivation of habit and fruit is correlated with chromosome basic number variation in the family Malpighiaceae.Key words -Malpighiaceae, Malpighioideae, Byrsonimoideae, chromosome number, habit, fruit types RESUMO -(Malpighiaceae: correlações entre hábito, tipo de fruto e número cromossômico básico). A família Malpighiaceae apresenta diferentes tipos de hábito, frutos e caracteres citogenéticos. Em geral, espécies lianas são consideradas as mais derivadas, seguidas, respectivamente, pelas arbustivas e arbóreas. O presente estudo propõe para Malpighiaceae uma relação entre a variação do número cromossômico básico e a derivação do hábito trepador e da morfologia dos frutos. Para estabelecer esta relação analisamos todas as contagens de cromossomos já relatadas para a família Malpighiaceae, sendo que a freqüência relativa destas contagens foi calculada para todos os gêneros estudados. Esta comparação mostrou a predominância de números cromossômicos baseados em x=5 ou 10 na sub-família Malpighioideae, predominantemente composta por lianas com frutos alados, enquanto que espécies de outros hábitos, com frutos não alados, apresentaram contagens baseadas em x=6, considerado o número básico menos derivado para a família, predominante na sub-família Byrsonimoideae. Baseados em consistentes dados estatísticos, e também na origem monofilética da família, admitimos a hipótese de que as derivações do hábito e dos tipos de fruto estão diretamente relacionadas com a variação do número cromossômico na família Malpighiaceae.Palavras-chave -Malpighiaceae, número cromossômico, número básico, hábito, tipos de fruto

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“…The karyotypes of 21 species of Serjania have been studied, in five of which two populations were analyzed (Hemmer and Morawetz, 1990;Nogueira et al, 1995;Solís Neffa and Ferrucci, 1997;Lombello and Forni-Martins, 1998), with the karyotypes showing a moderate degree of asymmetry and gradual differences in chromosome size. Although the predominance of m-type and smtype chromosomes has been noted, st-type and t-type chromosomes are also generally present.…”

Section: Karyotypes and Systematics In Paullinieaementioning

confidence: 99%

“…The most comprehensive studies on the karyology of Sapindaceae were done in the last decade (Ferrucci, 1989;Hemmer and Morawetz, 1990;Nogueira et al, 1995;Ferrucci and Solís Neffa, 1997;Ferrucci, 1997, 1998;Lombello and Forni-Martins, 1998), and chromosome numbers of 127 species have been reported and the complete karyotypes of 35 species are known, although only a few papers give information on interphase nucleus structure, chromosome condensing behavior, Giemsa Cbanding, NOR-banding and nucleolus counts (Eichhorn and Franquet, 1936;Guervin, 1961;Hemmer and Morawetz, 1990;Nogueira et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Cytotaxonomy of Sapindaceae with special reference to the tribe Paullinieae

Ferrucci

2000

Genet. Mol. Biol.

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Chromosomal studies and evolution in Sapindaceae

Cited by 28 publications

References 8 publications

Chromosome studies on Brazilian cerrado plants

Chromosome studies on Brazilian cerrado plants

Malpighiaceae: correlations between habit, fruit type and basic chromosome number

Cytotaxonomy of Sapindaceae with special reference to the tribe Paullinieae

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