Métodos de propagação do porta-enxerto 'Okinawa' e espaçamentos: efeitos no diâmetro do tronco, fenologia e produção de gemas em pessegueiros 'Aurora-1'

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Vegetative propagation of bauhinia x blakeana, an ornamental sterile tree

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Gibberellic acid in vegetative and reproductive development of Phalaenopsis orchid hybrid genus

O setor de floricultura movimenta cerca de um bilhão de dólares no Brasil e o desenvolvimento de técnicas direcionadas ao controle do florescimento é necessário. O presente trabalho avaliou a influência do ácido giberélico (GA3) no desenvolvimento vegetativo e reprodutivo de plantas jovens de Phalaenopsis FSNT 'Dai-Itigo', híbrido de coloração rósea. A aplicação do GA3 foi feita via pulverização foliar nas concentrações de 0, 125, 250, 500 e 1.000 mg L -1. O comprimento das folhas aumentou consideravelmente com o uso do GA3 em baixas concentrações, porém houve diminuição da largura foliar das plantas tratadas com esse fitorregulador. A aplicação do GA3 na concentração de 125 mg L -1 apresentou os melhores resultados para a promoção do florescimento e qualidade da floração deste híbrido de orquídea. Nesse tratamento, aproximadamente 50% das plantas pulverizadas apresentaram floração cerca de 6-12 meses antes da floração das plantas sem aplicação do fitorregulador. em conclusão, a qualidade da floração e das flores foi melhor no tratamento com 125 mg L -1 de GA3.

Dendroid colleters on vegetative and reproductive apices in Alibertia sessilis (Rubiaceae) differ in ultrastructure and secretion

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seasonal changes in vegetative growth and photosynthesis of Arabica coffee trees

Seasonal changes in vegetative growth, leaf gas exchanges, carbon isotope discrimination (Delta) and carbohydrate status were monitored in de-fruited coffee trees (Coffea arabica L.) grown in the field, from October 1998 through September 1999, in Vicosa (20degrees45'S, 42degrees15'W, 650 m a.s.l.), southeastern Brazil. of the total growth over the 12-month study period, 78% occurred in the warm, rainy season (October-March), and 22% during the cool, dry season (April-September). Throughout the active growth period, the rate of net carbon assimilation (A) averaged 8.6 mumol m(-2) s(-1), against 3.4 mumol m(-2) s(-1) during the period of reduced growth. In the active period, growth, unlike A or Delta, was strongly negatively correlated with air temperature. In contrast, growth and A were both correlated positively, and Delta correlated negatively, with air temperature during the reduced growth period. However, the depressions of A and growth might have simply run in parallel, without any causal relationship. Changes in A appeared to be largely due to stomatal limitations in the active growing season, with non-stomatal ones prevailing in the slow growth period. Foliar carbohydrates seemed not to have contributed appreciably to changes in growth rates and photosynthesis. (C) 2004 Elsevier B.V. All rights reserved.

Biologia floral e sistema de reprodução de Merostachys riedeliana (Poaceae: Bambusoideae)

Merostachys riedeliana Rupr. é uma espécie monocárpica com floração cíclica e muito freqüente em sub-bosques de fragmentos florestais do sul do estado de Minas Gerais, Brasil. Sua biologia floral e seu sistema de reprodução foram estudados e comparados com os de outros bambus. Devido ao complexo sistema de rizomas, formam touceiras vigorosas no interior da floresta, ocorrendo a interrupção na produção de novos colmos meses antes do aparecimento das primeiras inflorescências. O início da floração maciça e da morte da população ocorreu em outubro de 1998 e maio de 1999, respectivamente, com pico de floração durante a estação quente e chuvosa (dezembro e janeiro). As inflorescências espiciformes possuem, em média, 29 espiguetas. Estas são hermafroditas com três anteras poricidas e dois estigmas plumosos que se expõem durante a antese. O pólen é abundante e facilmente liberado das anteras pelo vento ou pelos visitantes. Apis mellifera L. e Trigona spinipes (F.) foram os visitantes mais freqüentes, atuando como pilhadores de pólen e, ocasionalmente, através de movimentos vibratórios, como elementos auxiliares para a dispersão do pólen. A alta pluviosidade durante a floração e a escassez de vento no sub-bosque da floresta, podem diminuir a efetividade da anemofilia. No entanto, vários caracteres morfológicos das espiguetas, queda de folhas e o hábito espacialmente agrupado, apontam para uma polinização pelo vento. Testes de polinização controlada, mostraram que M. riedeliana é autocompatível (ISI 0,99). A auto-incompatibilidade não favorece a formação de frutos em clones vegetais, ao passo que a autocompatibilidade poderia resultar em uma elevada produção de sementes. Assim, a possível ocorrência de clones de M. riedeliana nos fragmentos florestais, originados pelo crescimento vegetativo durante os intervalos reprodutivos de 30-32 anos, poderiam explicar o alto investimento na produção de espiguetas e a formação de frutos provenientes da autocompatibilidade.

On the taxonomic value of the anatomical structure of vegetative organs and inflorescence axis of Abolboda species (Xyridaceae - Poales)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of self-, chase and mixed self/cross-pollinations on pistil longevity and fruit set in Ceiba species (Bombacaceae) with late-acting self-incompatibility

Background and aims Late-acting self-incompatibility (LSI). in which selfed flowers fail to form fruits despite apparently successful growth of the pollen tubes to the ovules, is a contentious and still poorly understood phenomenon. Some studies have indicated pollen tube-pistil interactions, and major gene control. Others favour an early acting inbreeding depression explanation.Methods Experimental pollinations, including selfs (in a subsample of which the style was cut before pollen tubes reached the ovary), chase self/cross-pollinations, crosses, and mixed self/cross-pollinations were used to study floral/pistil longevity and effect on fruit set and seed yield in two Ceiba species known to have LSI.Results Self-pollinations, including those with a cut style, had extended floral longevity compared with unpollinated flowers. Chase pollinations in which cross-pollen was applied up to 3 h after selfing set fruits, but with reduced seed set compared with crosses. Those with cross-pollen applied at 4 and 8 h after self-pollination all failed to set fruits. Flowers subjected to 1 : 1 and 2 : 1 self/cross-pollinations all produced fruits but again with a significantly lower seed set compared with crosses.Conclusions Extended floral longevity initiated with self-pollen tubes growing in the style indicates some kind of pollen tube-pistil interaction. Fruit set only in chase pollinations up to 3 h implies that self-pollen tubes either grow more slowly in the style or penetrate ovules more slowly on arrival at the ovary compared with cross-tubes. This agrees with previous observations indicating that the incidence of penetrated ovules is initially lower in selfed compared with crossed pistils. However, the low seed yield from mixed pollinations indicates that self- and cross-pollen tubes arrive at the ovary and penetrate ovules more or less simultaneously. Possible explanations for these discordant results are discussed. (C) 2004 Annals of Botany Company.

Floral biology and late-acting self-incompatibility in Jacaranda racemosa (Bignoniaceae)

Breeding-system studies have been conducted with 38 of the approximately 800 species of Bignoniaceae, and self-incompatibility was found in 31 of these. In species for which the site of self-incompatibility barrier was studied, self-pollinated flowers consistently failed to develop into fruits, even though pollen tubes grew down to the ovary and penetrated most of the ovules. In this study, we have investigated the. oral biology and the breeding system in Jacaranda racemosa Chamisso, with hand-pollination experiments and the histology of post-pollination events. Flower anthesis lasted 1-3 days, and although the frequency of flower visitation was extremely low, natural pollination seemed to be effected mainly by medium-sized bees. Because the conspicuous staminodium favours eventual pollination by small bees, a possible role of the staminodium in the increase of potential pollinators is suggested. Hand-pollinations indicated that J. racemosa is a self-sterile species. Histological analysis of post-pollination events indicated the occurrence of a kind of late-acting self-incompatibility in which the processes of ovule penetration, fertilisation and endosperm initiation were slower in selfed than in crossed pistils. Until the time of self-pollinated pistil abscission, no signs of endosperm malfunction or proembryo development were observed in selfed pistils. Therefore, inbreeding depression is an unlikely explanation for self-sterility in J. racemosa.

Homomorphic self-incompatibility, with stylar rejection site, in Luehea grandiflora Mart. and Zucc. (Tiliaceae-Malvaceae s.l.)

The breeding system of Luehea grandiflora (Tiliaceae-Malvaceae s.l.) was investigated using hand pollinations and fluorescence microscopy studies of pollen tube growth. Although selfed flowers persisted for some 10 days, our study indicates that L. grandiflora is self-incompatible, with self pollen tube inhibition in the upper style, as occurs in many taxa with homomorphic, gametophytic self-incompatibility (GSI). L. grandiflora is only the second species reported within the Malvales with homomorphic stylar inhibition. This result is discussed within the context of a report for self-compatibility in this species, and we also consider the phylogenetic implications for the occurrence of GSI in the family Malvaceae s.l.

Morphology and anatomy of the vegetative organs and scapes from Aphorocaulon (Paepalanthus, Eriocaulaceae)

Estudou-se a anatomia de raízes, caules, folhas e escapos de espécies de Paepalanthus subseção Aphorocaulon. Estas plantas apresentam caules reduzidos com folhas em roseta, de onde crescem os paracládios (sistemas de inflorescências). As espécies apresentam raízes com epiderme unisseriada e córtex com células isodiamétricas. Tanto os caules reduzidos como os paracládios apresentam espessamento resultante da atividade do periciclo, denominado Meristema de Espessamento Primário (MEP). Ambos apresentam estrutura anatômica semelhante. Os escapos apresentam endoderme descontínua, periciclo sinuoso, o córtex apresenta costelas salientes (5-6). As folhas apresentam células epidérmicas alongadas no sentido longitudinal com paredes levemente espessadas, estômatos somente na face abaxial, com câmara subestomática especializada, feixes vasculares colaterais com bainha dupla. Essas estruturas anatômicas são comuns para as espécies da subseção Aphorocaulon. Algumas características anatômicas observadas nestas espécies são típicas de plantas que crescem nos campos rupestres.

Vegetative and productive aspects of organically grown coffee cultivars under shaded and unshaded systems

Although Coffea arabica species has its origin in the African understories, there is great resistance on the part of the Brazilian producers for growing this species under agroforestry systems as they fear that shading reduces production. This study aimed at evaluating some vegetative traits and the productivity of organically grown coffee (Coffea arabica L.) cultivars under shaded and unshaded systems. Twelve treatments consisting of two cultivation systems (shaded and unshaded) and six coffee cultivars were arranged in randomized blocks with four replicates, in a split-plot scheme. Shading was provided by banana (Musa sp.) and coral bean plants (Erythrinaverna). Shading delayed fruit maturation. Late maturation cultivars, such as the Icatu and the Obatã, matured early in both cultivation systems, while medium and early maturation cultivars presented late maturation. Cultivation in the shaded system increased the leaf area and the number of lower branches, decreased the number of productive nodes per branch, and increased the distance between the nodes and the number of leaves present in the branches. Cultivation in the unshaded system presented greater number of plants with branch blight in relation to plants grown in the shade. The productivity of the cultivars was not different, at 30.0 processed bags per hectare in the shaded system, and 25.8 processed bags per hectare in the unshaded system. The most productive cultivars in the shaded system were the Tupi, the Obatã, and the Catuaí, while no differences between cultivars were obtained in the unshaded system.

The effect of gene tubC on the vegetative growth of benomyl-resistant strains of Aspergillus nidulans

Two benomyl-resistant mutants, benD3 tubC41 and benD4 tubC42, of Aspergillus nidulans were isolated after UV treatment. The tubC mutations permitted good conidiation of these strains in culture media containing benomyl and were responsible for increasing their benomyl resistance levels. This implies that β3-tubulin, a product of the tubC gene, in addition to being involved in fungal conidiation, participates in the vegetative growth of the fungus. The tubC gene was located in linkage group I.

Systematic vegetative anatomy and ensiform leaf development in Xyris (Xyridaceae)

Ensiform leaf development in monocotyledons follows a broadly similar sequence in a wide range of relatively unrelated taxa, indicating a plastic developmental pattern, possibly associated with stressed environmental conditions, since Xyris species tend to grow in relatively damp but nutrient-poor environments. The bifacial leaf sheath surrounds the apex and the subadjacent primordium. A conical unifacial leaf tip 'Vorlauferspitze' is established at an early stage, followed by extension growth in the region behind it, generating a unifacial ensiform blade. Root and rhizome structure are also described in a systematic context, particularly in comparison with related taxa in Xyridaceae and other commelinoid monocotyledons, although information on these structure is relatively sparse.