Página 1 dos resultados de 2789 itens digitais encontrados em 0.014 segundos

Biologia reprodutiva de Heros efasciatus Heckel, 1840 (Pisces, Cichlidae) na Reserva de Desenvolvimento Sustentável Amanã-AM, visando seu manejo sustentável; Reproductive biology of Heros efasciatus Heckel,1840 (Pisces, Cichlidae) in the Amanã Sustainable Reserve (Amazonas, Brazil), aiming at sustainable management of the species

FAVERO, Jana Menegassi del; POMPEU, Paulo dos Santos; PRADO-VALLADARES, Ana Carolina
Fonte: Instituto Nacional de Pesquisas da Amazônia Publicador: Instituto Nacional de Pesquisas da Amazônia
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
66.08%
Com o principal objetivo de fornecer ferramentas para auxiliar na implementação do manejo sustentável de peixes ornamentais na Reserva de Desenvolvimento Sustentável Amanã, Amazonas, foi realizado o estudo da biologia reprodutiva de Heros efasciatus Heckel, 1840, um ciclídeo com potencial ornamental e com poucos trabalhos sobre a sua biologia e ecologia, apesar de já ser comercializado em algumas regiões amazônicas. Coletas bimestrais foram realizadas de fevereiro de 2006 a janeiro de 2007 em dez igarapés contribuintes do Lago Amanã e Urini, sendo utilizados três aparelhos de pesca (rede de arrasto, rapiché e armadilha tipo matapi) e ainda galhadas artificiais nas amostragens realizadas próximas aos lagos. Foram capturados 140 exemplares de H. efasciatus, sendo 50 fêmeas, 42 machos, e 46 indivíduos cujo sexo não foi identificado devido ao pequeno tamanho. O tipo de crescimento encontrado foi isométrico, sendo que o maior indivíduo observado apresentava 174 mm e o menor 14 mm. Os resultados encontrados auxiliarão na adoção de medidas de manejo, como a determinação de tamanhos mínimos de captura, superiores aos tamanhos médios de maturação (97 mm para as fêmeas) e o estabelecimento de períodos de defeso durante a época de sua reprodução (outubro a janeiro). A pequena abundância de indivíduos da espécie...

Reproductive biology of Trichocentrum pumilum: an orchid pollinated by oil-collecting bees

PANSARIN, E. R.; PANSARIN, L. M.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.14%
The reproductive biology, reward production and pollination mechanism of Trichocentrum pumilum were studied in a gallery forest in the interior of the State of Sao Paulo, southeast Brazil. The floral visitors and pollination mechanism were recorded, and experimental pollinations were carried out in order to determine the breeding system of this species. Trichocentrum pumilum blooms in spring. Each paniculate inflorescence bears an average of 85 flowers that present a central yellow callus and finger-like trichomes on the lateral lobes of the lip. A lipoidal substance is produced and stored among these trichomes. In the studied population, T. pumilum is exclusively visited and pollinated by two bee species (Tetrapedia diversipes and Lophopedia nigrispinis). Pollinaria are deposited on mouthparts of bees during collection of the lipoidal substance from the lateral lobes of the labellum. Trichocentrum pumilum is self-incompatible and pollinator-limited. Natural fruit set was low (9%, compared to 45% in experimentally cross-pollinated flowers). Potentially viable seed exceed 97% in fruits obtained through cross-pollination and in natural conditions (open pollination).; State of Sao Paulo Research Foundation (FAPESP); CNPq

Slipper lobsters (Scyllaridae) off the southeastern coast of Brazil: relative growth, population structure, and reproductive biology

Duarte, Luis Felipe de Almeida,; Rodrigues, Evandro Severino; Pinheiro, Marcelo A A; Gasalla, Maria de los Angeles
Fonte: Washington DC Publicador: Washington DC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.13%
The hooded slipper lobster (Scyllarides deceptor) and Brazilian slipper lobster (S. brasiliensis) are commonly caught by fishing fleets (with double-trawling and longline pots and traps) off the southeastern coast of Brazil. Their reproductive biology is poorly known and research on these 2 species would benefit efforts in resource management. This study characterized the population structure of these exploited species on the basis of sampling from May 2006 to April 2007 off the coast of Santos, Brazil. Data for the absolute fecundity, size at maturity in females, reproductive period, and morphometric relationships of the dominant species, the hooded slipper lobster, are presented. Significant differential growth was not observed between juveniles and adults of each sex, although there was a small investment of energy in the width and length of the abdomen in females and in the carapace length for males in larger animals (>25 cm in total length [TL]). Ovigerous females were caught more frequently in shallow waters in August–September than in January–February, indicating a possible migration to spawn. Fecundity ranged from 55,800 to 184,200 eggs (mean fecundity: 115,000 [standard deviation 43,938] eggs). The spawning period occurred twice a year...

Reproductive Biology of Weakly Electric fish Eigenmannia trilineata López and Castello, 1966 (Teleostei, Sternopygidae)

Giora, Julia; Fialho, Clarice Bernhardt
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
66.16%
Este trabalho descreve a biologia reprodutiva de uma população do peixe elétrico Eigenmannia trilineata do Sul do Brasil. São apresentadas informações a respeito do período reprodutivo, fecundidade, tipo de desova, tamanho de primeira maturação, morfologia e histologia das gônadas da espécie, relacionando estes dados a caracteres alimentares e abióticos. A espécie apresentou período reprodutivo relativamente longo, com fecundidade relativa de 0,27 ovócito por miligrama do peso da fêmea e desova do tipo parcelada. O tamanho de primeira maturação gonadal estimado para fêmeas foi 80,5 mm e para machos, 63,5 mm de comprimento total. A proporção sexual, testada pelo teste X2 (a= 0.01), foi de 1:1 durante todos os meses amostrados; dimorfismo sexual relacionado ao comprimento total foi detectado, possuindo os machos um maior comprimento total. Dos fatores abióticos testados, fotoperíodo e condutividade da água mostraram correlação significativa com o IGS das fêmeas, enquanto somente fotoperíodo apresentou-se relacionado ao IGS dos machos.; This study described the reproductive biology of a population of the weakly electric fish Eigenmannia trilineata from southern Brazil, providing the information on the estimation of reproductive period...

Ecology and reproductive biology of two species of Aplastodiscus (Anura : Hylidae) in the Atlantic forest, Brazil

Zina, Juliana; Haddad, Celio F. B.
Fonte: Taylor & Francis Ltd Publicador: Taylor & Francis Ltd
Tipo: Artigo de Revista Científica Formato: 1831-1840
ENG
Relevância na Pesquisa
66.13%
The present study was conducted in the Serra do Japi in the State of São Paulo, Brazil. From March 2004 to January 2006 we studied the ecology and reproductive biology of two sympatric species of Aplastodiscus in three different habitats: lake, stream, and swamp. The majority of A. leucopygius males in calling activity were recorded during the rainy season and during sporadic rains in the dry season (April to September). The same was observed for A. arildae. Most courtship displays of A. leucopygius were observed mainly during the rainy period and only one courtship behaviour was observed for A. arildae during a rainy night, in December 2005. Aplastodiscus leucopygius males were found in activity in the three habitats surveyed. In contrast, males of A. arildae were found in only one habitat (stream). Spatial distribution seems to be the main mechanism of reproductive segregation between the studied species.

Reproductive biology in the primitive relic Angiosperm Drimys brasiliensis (Winteraceae)

Gottsberger, Gerhard; Silberbauer-Gottsberger, Ilse; Ehrendorfer, Friedrich
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 11-39
ENG
Relevância na Pesquisa
66.13%
From field observations on Drimys 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 that D. 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 diurnal Coleoptera, Diptera and Thysanoptera 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 in D. brasiliensis are discussed in a wider context, compared with data from other Magnoliidae, and related to aspects of early Angiosperm evolution. © 1980 Springer-Verlag.

Reproductive biology and moulting cycle of the crab Callinectes ornatus (Decapoda, Portunidae) from the Ubatuba region, Sao Paulo, Brazil

Mantelatto, Fernando Luis Medina; Fransozo, Adilson
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 63-76
ENG
Relevância na Pesquisa
66.16%
To investigate the reproductive biology of Callinectes ornatus gonadal and moulting cycles were studied over two consecutive years in the Ubatuba region. Six stages of gonadal development were detected in females and four in males. Observations on the number of ovigerous females, on the moulting stages of males and females, and on the percentage of individuals exhibiting mature gonads reveal a continuous reproductive cycle, the stages of which progress at different rates. These data support the hypothesis that C. ornatus shows staggered spawning, with possibly more than one annual reproductive period. A pause in growth before the terminal moult may occur in this species.

The reproductive biology of Diplodus argenteus (Sparidae) in the coastal upwelling system of Cabo Frio, Rio de Janeiro, Brazil

David, G. S.; Coutinho, R.; Quagio-Grassiotto, I.; Verani, J. R.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 439-447
ENG
Relevância na Pesquisa
66.2%
The reproductive biology of the seabream Diplodus argenteus, a dominant coastal fishery species, was investigated over two consecutive seasons (2001-2002) at Cabo Frio, Brazil, a low-latitude upwelling system. The sex ratio was dominated by females (1.4:1.0) and the length-at-50% sexual maturity (females) was 203mm total length. Females were multiple spawners and the reproductive pattern appeared to be digynous protandrous hermaphroditism. Monthly variations in gonadosomatic index and proportion of ripe females indicated that reproductive activity occurred from late winter to summer (August-February), following coastal upwelling. Copyright © NISC Pty Ltd.

Reproductive biology and pollination mechanisms of Epidendrum secundum (Orchidaceae). Floral variation: a consequence of natural hybridization?

Pansarin, Emerson Ricardo; Amaral, Maria do Carmo Estanislau do
Fonte: Blackwell Publishing Publicador: Blackwell Publishing
Tipo: Artigo de Revista Científica Formato: 211-219
ENG
Relevância na Pesquisa
66.08%
The phenology, flower morphology, pollination mechanism and reproductive biology of Epidendrum secundum were studied in a semi-deciduous forest at the Serra do Japi (SJ), and in the Atlantic rain forest of Picinguaba, both natural reserves in the State of Sao Paulo, southeastern Brazil. E. secundum flowers all year round, with a flowering peak between September and January. This species is either a lithophytic or terrestrial herb in the SJ, whereas, in Picinguaba, it grows mainly in disturbed areas along roadsides. E. secundum is pollinated by several species of diurnal Lepidoptera at both study sites. In Picinguaba, where E. secundum is sympatric with E. fulgens and both share the same pollinators, pollen transference between these two species was recorded. E. secundum is self-compatible but pollinator-dependent. It is inter-compatible with E. fulgens, producing fertile seeds. In contrast to the population of the SJ, in the Picinguaba region, floral morphology is quite variable among plants and some individuals present flowers with characteristics in-between both sympatric species, suggesting that natural hybridization occasionally occurs. The anthropogenic perturbation is probably the cause of the occurrence of E. secundum in the Picinguaba region...

Reproductive biology of Trichocentrum pumilum: an orchid pollinated by oil-collecting bees

PANSARIN, E. R.; PANSARIN, L. M.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.14%
The reproductive biology, reward production and pollination mechanism of Trichocentrum pumilum were studied in a gallery forest in the interior of the State of Sao Paulo, southeast Brazil. The floral visitors and pollination mechanism were recorded, and experimental pollinations were carried out in order to determine the breeding system of this species. Trichocentrum pumilum blooms in spring. Each paniculate inflorescence bears an average of 85 flowers that present a central yellow callus and finger-like trichomes on the lateral lobes of the lip. A lipoidal substance is produced and stored among these trichomes. In the studied population, T. pumilum is exclusively visited and pollinated by two bee species (Tetrapedia diversipes and Lophopedia nigrispinis). Pollinaria are deposited on mouthparts of bees during collection of the lipoidal substance from the lateral lobes of the labellum. Trichocentrum pumilum is self-incompatible and pollinator-limited. Natural fruit set was low (9%, compared to 45% in experimentally cross-pollinated flowers). Potentially viable seed exceed 97% in fruits obtained through cross-pollination and in natural conditions (open pollination).; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reproductive biology of the species Leucoraja naevus from Portuguese continental waters

Maia, Catarina
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Dissertação de Mestrado
Publicado em //2010 ENG
Relevância na Pesquisa
56.27%
Dissertação de mest., Biologia Marinha, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2010; Skate populations tend to be highly vulnerable to exploitation as a result of the main life history characteristics (slow growth, late maturity and low fecundity). The cuckoo ray, Leucoraja naevus, one of the skate species landed in Portugal, is mainly a by-catch species from the artisanal mixed-fishery, and for this reason it is very difficult to acquire information about its basic biology. The two main goals of the present work were to estimate the length at first maturity, fecundity and reproductive cycle of the species Leucoraja naevus and to compare the microscopic structure and chemical nature of the secretions produced by the oviducal gland of the species Leucoraja naevus with other skate species taking into account their reproductive strategy. Although the species has been studied in other NE Atlantic geographic areas, namely Celtic Sea, Irish Sea and North Sea, this study is the first to provide information on the reproductive biology of Leucoraja naevus in Southern European waters. Length at first maturity was estimated at 57 cm and 55 cm TL for males and females, respectively. Active females were observed in every months of the year suggesting that reproduction may occur year round...

Occurrence of the Indo-Pacific freshwater prawn Macrobrachium equidens Dana 1852 (Decapoda, Palaemonidae) on the coast of Brazilian Amazonia, with notes on its reproductive biology

Maciel,Cristiana R; Quadros,Manoel L; Abrunhosa,Fernando; Bastos,Sandra; Schneider,Horacio; Sampaio,Iracilda
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
Relevância na Pesquisa
66.08%
The freshwater prawn Macrobrachium equidens, which is native species of the Indo-Pacific Region, was recorded for the first time on the Amazon coast of Brazil. This species was found to inhabit the same environment as two native Macrobrachium species, M. amazonicum and M. acanthurus, and is morphologically very similar to the latter. The identification of the species was confirmed by the genetic analysis of sequences of the mitochondrial Cytochrome Oxidase (COI) gene. A detailed description of the morphological features and reproductive biology of M. equidens in this new environment is presented.

Population structure and reproductive biology of Metamysidopsis neritica (Crustacea: Mysidacea) in a sand beach in south Brazil

Calil,Patrícia; Borzone,Carlos A.
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2008 EN
Relevância na Pesquisa
66.08%
Mysidacea are common sublittoral crustaceans that inhabit all coasts in the world. In this study, the population characteristics and the reproductive biology of Metamysidopsis neritica Bond-Buckup & Tavares, 1992 were studied in the surf zone of a south Brazilian beach (Atami). Mysids were sampled at monthly intervals from August, 1999 to July, 2000 (total of 29,490 individuals). Individuals were classified into six population categories. The highest abundance occurred in May (8,665) and August (6,415), and lowest in September (336) and December (368). Three main generations were identified, namely the summer, fall and winter generations. The winter generation was the longest (four to five months). The fall generation lasted four months, and the summer one extended from three to four months. Ovigerous females occurred throughout the year, with a greater proportion in July. The number of eggs or larvae varied from one to 16. Weak associations were found between female length and egg number, egg volume, and the number of larvae with and without eyes. Egg volume increased during the coldest season, whereas the smallest values were recorded during summer. These results suggest a possible direct relationship between egg volume and generation longevity.

Reproductive biology of a tetragonopterinae (osteichthyes, characidae) of the Ubatiba fluvial system, Maricá - RJ

Mazzoni,Rosana; Petito,Jaqueline
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/1999 EN
Relevância na Pesquisa
66.08%
Aspects of the reproductive biology of one Tetragonopterinae was assessed in the Ubatiba river - Maricá / RJ. Length structure and mean size suggested sexual dimorphism, females reaching larger sizes than males. The onset of sexual maturity occured at 2.8cm for both the sexes. Fecundity, determined on ripe ovaries, showed positive correlation to females size and weight and varied from 595 to 5520 for 3.9cm and 6.2cm lengths respectively. The spawning type, defined as total, was determined by the oocyte diameter frequency from ovaries in different development stages. The frequency distribution of ovarian/testis maturation stages, associated with the temporal variation of the gonadosomatic index, suggested that the reproduction period was prolonged along the whole annual cycle.

Reproductive biology of weakly electric fish Eigenmannia trilineata López and Castello, 1966 (Teleostei, Sternopygidae)

Giora,Júlia; Fialho,Clarice Bernhardt
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 EN
Relevância na Pesquisa
66.16%
This study described the reproductive biology of a population of the weakly electric fish Eigenmannia trilineata from southern Brazil, providing the information on the estimation of reproductive period, fecundity, spawning type, first maturation size, and analysis of gonadal morphology and histology of the species, relating these data to alimentary and abiotic characters. The species showed a relatively long reproductive period, a relative fecundity of 0.27 oocytes per mg of total weight and a parcelled spawning type. First maturation size estimated for the females was 80.5 mm and for the males 63.5 mm of total length. Sex ratio did not differ from 1:1 under a X²test (α= 0.01) during all the sampled months. Sexual dimorphism was related to total length, and males had larger total length than females. The abiotic factors photoperiod and water conductivity presented significant correlations with female GSI, while male GSI presented a significant correlation only with photoperiod.

Reproductive biology of a characidiinae (osteichthyes, characidae) from the Ubatiba river, Maricá -- RJ

MAZZONI,R.; CARAMASCHI,E. P.; FENERICH-VERANI,N.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2002 EN
Relevância na Pesquisa
66.2%
The Ubatiba river is a coastal stream subject to stochastic spates all over the year and, Characidium sp.n. is among the twenty-two species that compose its ichthyofauna. In this study we analyse some traits of its reproductive biology and discuss whether the adopted strategy has causal relationship with the environmental variables. Specimens were collected in the upper Ubatiba river. Samplings, were carried out monthly by electrofishing, between Oct./94 and Sep./95. Some differences between male and female strategies were observed. Females were significantly (p < 0.05) bigger than males; length -- weight relationship was different (p < 0.05) between sexes with the onset of sexual maturity occuring at smaller sizes among males. Reproductive investment is high for both males and females but higher for males, maximum Gonadosomatic Index for females and males were 40.97% and 44.90%, respectively. Reproductive specimens were registered all over the year, suggesting continuous reproduction. High values of fecundity were also registered varying from 1342 to 5535 eggs for ripe females of 4.4 and 7.0 cm, respectively and an amount of 1105 oocytes per grams of fish. We suggest that differences in the reproductive strategy, between sexes, determine the observed patterns in the size structure; the absence of males in the higher SL classes could be a consequence of high mortality rates and/or reduction in the growth rates as a precocity consequence in the onset of reproduction and/or high reproductive investment. Relationship between continuous reproduction and environmental condition could be explained as an adaptation to maximise supervivency of the young fishes that is: guarantee the species maintenance in a stochastic environment.

Reproductive biology of Astyanax janeiroensis (Osteichthyes, Characidae) from the Ubatiba River, Maricá, RJ, Brazil

Mazzoni,R.; Mendonça,R. S.; Caramaschi,E. P.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2005 EN
Relevância na Pesquisa
66.19%
Aspects of the reproductive biology of Astyanax janeiroensis in the Ubatiba river in Maricá, RJ, Brazil were evaluated in order to ascertain whether the strategy adopted by the species is causally related to environmental variables. Specimens were collected on a monthly basis from October 1994 to September 1995, through electrofishing. The Sex ratio was not significantly different from the expected frequency of 1:1 (G = 1.29; p > 0.50); nonetheless, considering three standard length classes, significantly larger numbers of females were recorded for the higher SL class (G = 11.07; p < 0.01). Size at first maturation showed no significant differences between sexes. Length-weight ratio analyses showed negative allometry for males and isometry, for females. Length structure was significantly different between sexes, suggesting that females are larger than males (D = 0.027, p < 0.01). Reproductive specimens were recorded during nine months of the annual cycle. Seasonal variations of reproductive specimens belonging to two different standard length classes displayed an asynchronous behavior, with larger specimens having a longer reproductive period and smaller ones reproducing for fewer months during the annual cycle. High values of fecundity (F)...

The population density effects on the reproductive biology of the snail Bradybaena similaris (Férussac, 1821) (Mollusca, Gastropoda)

Oliveira,CS. de; Vasconcellos,MC.; Pinheiro,J.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2008 EN
Relevância na Pesquisa
66.08%
The influence of population density on some aspects of the reproductive biology of the snail Bradybaena similaris was studied. Molluscs were maintained under 0.2 (isolated), 0.3, 0.6, 1.0, 1.3 and 1.7 snail/m² densities. The animals maintained under 0.3 and 0.6 snail/m² showed the lowest numbers of eggs laid/snail, being the highest value observed to the 1.7 snail/m². The hatching of the snails maintained under 0.3 snail/m² density, begun at the 21st day after laying, and the maximum time required to the hatching was 36 days was observed to the eggs came from snails maintained under the densities 0.6, 1.0, 1.3 snail/m², respectively. The highest percentage hatchability (55.56%) was observed to isolated snails. The galactogen content in the albumen gland did not seem to accompany the alterations occurred in the reproduction of B. similaris in response to the different population densities.

Reproductive biology of the genus Androcymbium (Colchicaceae) in western southern Africa

Membrives, Núria; Caujapé-Castells, Juli; Ardanuy, Amparo; Pedrola-Monfort, Joan
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Article; info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2002 ENG
Relevância na Pesquisa
66.19%
We characterized reproductive biology traits in 32 populations belonging to 17 western southern African taxa of the genus Androcymbium (Colchicaceae) using artificial pollination experiments conducted under homogeneous environmental conditions in a greenhouse. The species surveyed displayed differences in phenological periods between emergence, flowering and senescence. We observed three types of vegetative reproduction that give rise to (1) globose corms, (2) compressed corms, and (3) a dichotomous underground networking of corms that, unlike (1) and (2), entails the elongation of the stem. Seed germination was low in most of the populations. The artificial pollination experiments allowed us to recognize three reproductive systems: self-incompatible, preferentially self-incompatible and self-compatible. In most cases, the reproductive system inferred from the artificial pollination experiments disagreed with the classification according to the P/O ratio. The variability observed in nectar characteristics (odour, amount and moment of the day of nectar production) suggests different pollinators for the taxa surveyed. Based on these data, we inferred three reproductive strategies in Androcymbium that assure both species' survival and the maintenance of levels of genetic variability: (1) preferential selfincompatibility associated with morphological traits that favour the attraction of pollinators; (2) preferential self-incompatibility with high levels of vegetative reproduction; and (3) self-compatibility with high levels of seed production.; Se estudiaron diversos aspectos de la biología reproductiva en 32 poblaciones pertenecientes a 17 taxones del género Androcymbium (Colchicaceae) de la región Occidental de Suráfrica usando experimentos de polinización artificial realizados en invernaderos bajo condiciones ambientales homogéneas. Las especies estudiadas mostraron diferencias en los períodos fenológicos entre la emergencia...

Biologia reprodutiva de etnovariedades de mandioca; Reproductive biology of cassava landraces

Silva, Rainério Meireles da; Bandel, Gerhard; Faraldo, Maria Inez Fernandes; Martins, Paulo Sodero
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/03/2001 POR
Relevância na Pesquisa
66.22%
O conhecimento da biologia reprodutiva da mandioca é essencial para o desenvolvimento de programas de melhoramento genético e compreensão do processo de domesticação. Este trabalho avalia aspectos que influenciam a reprodução sexuada, tais como morfologia floral, ecologia da polinização, produção e viabilidade dos grãos de pólen, apomixia, produção e germinação de sementes de etnovariedades de mandioca coletadas em roças de caboclos e índios da Região Amazônica e do Estado de São Paulo. Os aspectos da biologia reprodutiva foram estudados a partir de avaliações de campo e coleta de botões florais e sementes. Os experimentos foram realizados em Piracicaba, SP. Constatou-se alteração na morfologia floral da etnovariedade DG-55, a qual possui flores hermafroditas, e DG-65 e variedade Mantiqueira, que apresentaram menor número de óvulos por ovário. A abelha (Apis mellifera) foi o principal polinizador da mandioca. Houve variação significativa no número e viabilidade de grãos de pólen, constatando-se que as anteras do verticilo superior da flor masculina apresentaram, significativamente, maior número de grãos de pólen. Não foi constatada apomixia. Foi detectado maior número de frutos com duas ou três sementes. No entanto...