Paclobutrazol no crescimento e desenvolvimento in vitro e na aclimatização de Sophronitis cernua (Lindl.) Lindl. e Brassavola flagellaris Barb. Rodr. (Orchidaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo químico e das atividades citotóxica, antioxidante e antifúngica de Prunus myrtifolia L. (Urban.) (ROSACEAE)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Growth and flowering of miltonia flavescens lindl. var. stellata regel orchid under different doses of a slow release fertilizer

The Orchidaceae is one of the most numerous and diversified families in the Plant Kingdom. Miltonia flavescens Lindl. is a native orchid to the southern region of Brazil. Studies related to the nutrition and fertilization of orchids are scarce, specific and existent only for few species. The objective of this work was to evaluate the effect of different doses of a slow release fertilizer (Osmocote (R) 9/15/12 + micro) on the development of M. flavescens var. stellata Regel cultivated in pots with pine bark and coconut fiber (1:1, v:v) as the substrate. The treatments consisted of: no fertilizer application (control), application of 2.5 g, 5 g and 10 g of fertilizer per liter of substrate. The experimental design was set in randomized blocks, with five replications and three plants per plot. The experiment was carried out along 25 months and the fertilizer was applied every five months. The evaluated plant parameters were: length of the longest pseudobulb, number of pseudobulbs, diameter of pseudobulbs, number of shoots, number of leaves and flowering. There was a significant increment on all evaluated characteristics with the increase of the fertilizer dose. The highest dose provided a more profuse flowering, with a larger number of flower stems and flowers, in addition to bigger flower stems and flowers. These results show that the supply of nutrients in an appropriate amount is of a great importance for the development and flowering of M. flavescens.

Estrutura populacional de Oeceoclades maculata Lindl. (Orchidaceae), em um mosaico vegetacional (FEENA) da Floresta Estadual Edmundo Navarro de Andrade, Rio Claro, São Paulo

O objetivo do presente estudo foi avaliar a estrutura de população de O. maculata, através de sua distribuição espacial e estrutura de habitat, comparando características físicas e biológicas em diferentes fisionomias de Pinus spp. e Eucalyptus spp.. Foram montadas 86 parcelas de 5m por 10m, distribuídas uniformemente entre 4 áreas pré-estabelecidas de fisionomias distintas. Os indivíduos levantados foram separados em duas classes etárias, jovens e adultos, e contabilizou-se a taxa de predação, número de pseudobulbos e número de folhas. Os parâmetros ambientais avaliados foram cobertura herbácea, densidade de dossel, luminosidade e umidade de serrapilheira. A espécie apresentou densidades bastante elevadas nas áreas de plantios de eucalipto (1224 e 1733 indivíduos por hectare) e baixas nos plantios de pinus (88 e 26 individuos por hectare) o que levou as análises a se concentrarem nas fisionomias compostas por eucaliptos. O padrão de distribuição da espécie foi o agregado em todos os ambientes. Indivíduos adultos apresentaram significativamente um número médio de pseudobulbos maior que indivíduos jovens (Mann-Whitney; U = 24248.500; p<0,001), porém a diferença no número de folhas não foi significativa. A taxa de predação foliar em O. maculata entre as áreas de eucaliptos apresentou variação significativa. A variação do total de folhas predadas foi confirmada pelo teste Qui-quadrado de Pearson (X²=115.487; gl=1; p<0.001). A comparação de médias, com base no teste de Kruskal-Wallis, para cobertura de dossel (H(3,N=102)=28,534 p<0,001) e cobertura herbácea H(3,N=94)=28,246, p<0,001, mostrou taxas menores nas áreas de eucalipto. A umidade da serrapilheira foi menor (36,5%) nos locais onde a espécie apresentou agrupamentos, quando comparada aos locais de ausência (47,5%). Oeceoclades maculata Lindl. possui grande capacidade para colonizar ambientes... (Resumo completo, clicar acesso eletrônico abaixo)

Resíduos agrícolas e argila expandida no cultivo da orquídea Oncidium baueri Lindl.

For orchid cultivation in containers is essential to select the right substrate, since this will influence the quality of the final product, it serve as a support for the root system of the plants. This study aimed to evaluate different agricultural residues and expanded clay in Oncidium baueri Lindl. orchid cultivation. The plants were subjected to treatments: pinus husk + carbonized rice husk, pinus husk + coffee husk, pinus husk + fibered coconut, pecan nut husk, expanded clay, fibered coconut, coffee husk, carbonized rice husk, pinus husk. After eleven months of the experiment, the following variables were evaluated: plant height; largest pseudo-bulb diameter; number of buds; shoot fresh dry matter; the longest root length; number of roots; root fresh matter; root dry matter; and electric conductivity; pH and water retention capacity of the substrates. Except the expanded clay, the other substrates showed satisfactory results in one or more traits. Standing out among these substrates pinus husk + coffee husk and pine bark + fibered coconut, which favored the most vegetative and root characteristic of the orchid. The mixture of pinus husk + coffee husk and pinus husk + fibered coconut, provided the best results in vegetative and root growth of the orchid Oncidium baueri and the expanded clay did not show favorable results in the cultivation of this species.

Fenologia reprodutiva e distribuição espacial de Oeceoclades maculata (Lindl.) Lindl. (Orchidaceae) em Cerrado do município de Mogi Guaçu, São Paulo, Brasil

Oeceoclades aculate (Lindl.) Lindl., an invasive orchid, was analyzed as to its reproductive phenology and spatial distribution, correlation between abundance of mature and immature individuals, and verifying these with microclimate patterns in the Cerrado (savanna-like vegetation) of Mogi Guacu, Sao Paulo State, Brazil. For the reproductive phenology 100 plants were followed and the distribution pattern was identified by the Morisita Index (MI) and the Variance Ratio/Average (R) in 20 plots of 20x10m, reduced to 10x10m afterwards. The phenology presented seasonality, with flowering from November to February, fructification from February to June, and dehiscence from June to July. Mature and immature individuals aggregated and correlated to each other, indicating dependence between the ontogenetic stages. The luminosity was the preponderant microclimatic factor in the allocation of plants. Seasonal climatic changes and intensity of anthropogenic disturbances seem to be more important for the establishment of the species than microclimate.

Biotic versus abiotic pollination in Oeceoclades maculata (Lindl.) Lindl. (Orchidaceae)

Geographical variation in the reproductive biology of widespread species often occurs at their distributional boundaries. We sought to determine whether such variation has occurred in an invasive orchid, Oeceoclades maculata, across its naturalized range. We compared its reproductive biology in a Brazilian population with that published for a population on the Caribbean island of Puerto Rico. In the state of Sao Paulo, O. maculata flowers between December and February, at the height of the rainy season. Similar fruit sets were observed in manual self (76%) and cross (70.4%) pollination treatments. The fruit set of plants protected from both pollinators and rainfall was 6.1%, whereas plants exposed only to rainfall had a fruit set of 41.4%, slightly less than the controls (48.3%). Like the Puerto Rico population, reproduction is primarily through rain-assisted autogamy, but unlike observations made on the island, outcrossing can eventually occur. We observed two butterfly species (Heliconius ethilla narcaea and Heliconius erato phyllis) pollinating O. maculata. Secretory epidermal cells and trichomes of the spur lumen produced 0.7 mu L of 25% (sucrose equivalents) nectar per flower each morning, which was stored in a dilated basal portion of the spur and reabsorbed by the afternoon. Thus, geographical variation in reproductive biology exists across the broad invasive range of O. maculata.

Role of reactive oxygen and nitrogen species in the response of Prunus spp. to bicarbonate

In calcareous soils, which are a large share of agricultural soils worldwide, iron availability is limited. Consequently, the whole plant physiology is affected, because of the key role of iron in redox metabolism, resulting in reduced crop yield and quality. Peach cultivation is economically important in northern Italy, and is easily subjected to iron chlorosis. The management of iron nutrition in peach includes grafting on bicarbonate-tolerant rootstocks; other forms of management may be expensive and environmentally impacting. Four genotypes, used as rootstocks for peach and characterized by different degrees of tolerance to chlorosis, were tested in vitro on optimal and bicarbonate-enriched medium. Their redox status and antioxidant responses were assayed; the production and possible roles of nitric oxide (NO) and related compounds were also studied. The most sensitive genotypes show a stronger reduction of the antioxidant enzymatic activities and an increased oxidative stress. A high production of NO was found to be associated to resistant genotypes, whereas sensitive genotypes reacted to stress by downregulating nitrosoglutathione reductase activity. Therefore, NO is proposed to improve the internal iron availability, or to stimulate iron intake.

Impact of forest fragmentation and disturbance on the endangered tropical tree Prunus africana (Rosaceae)

Anthropogene Fragmentierung und Störung von Wäldern beeinflussen ökologische Prozesse. Darüber hinaus werden genetische Drift und Inzucht verstärkt und die Fitness von Populationen beeinträchtigt. Um die Einflüsse von Fragmentierung und Störung auf die Biodiversität und Prozesse in tropischen Wäldern zu ermitteln, habe ich im „Kakamega Forest“, West-Kenia, die Baumart Prunus africana genauer untersucht. Dabei lag der Fokus auf (i) der Frugivorengemeinschaft und Samenausbreitung, (ii) der Kleinsäugergemeinschaft im Kontext der Samenprädation und (iii) der genetische Populationsstruktur von Keimlingen und adulten Bäumen. Der Vergleich von Keimlingen mit adulten Bäumen ermöglicht es, Veränderungen im Genfluss zwischen Generationen festzustellen. Die Ergebnisse zeigten, dass im untersuchten Waldgebiet insgesamt 49 frugivore Arten (Affen und Vögel) vorkommen. Dabei lag die Gesamtartenzahl im zusammenhängenden Wald höher als in den isoliert liegenden Fragmenten. An den Früchten von P. africana konnten insgesamt 36 Arten fressend beobachtet werden. Hier jedoch wurden in Fragmenten eine leicht erhöhte Frugivorenzahl sowie marginal signifikant erhöhte Samenausbreitungsraten nachgewiesen. Der Vergleich von stark gestörten mit weniger gestörten Flächen zeigte eine höhere Gesamtartenzahl sowie eine signifikant höhere Frugivorenzahl in P. africana in stark gestörten Flächen. Entsprechend war die Samenausbreitungsrate in stark gestörten Flächen marginal signifikant erhöht. Diese Ergebnisse deuten darauf hin, dass die quantitative Samenausbreitung in fragmentierten und gestörten Flächen etwas erhöht ist und somit eine gewisse Artenredundanz besteht, die den Verlust einzelner Arten ausgleichen könnte. Prunus africana Samen, die auf dem Boden lagen, wurden hauptsächlich von einer Nagerart (Praomys cf. jacksonii) erbeutet. Dabei war in gestörten Waldbereichen eine tendenziell höhere Prädatoraktivität zu beobachten als in weniger gestörten. Zudem waren einzelne Samen im Gegensatz zu Samengruppen in gestörten Flächen signifikant höherem Prädationsdruck ausgesetzt. Diese Ergebnisse zeigen, dass Fragmentierung sowie anthropogene Störungen auf unterschiedliche Prozesse im Lebenszyklus eines tropischen Baumes gegensätzliche Effekte haben können. Eine Extrapolation von einem auf einen anderen Prozess kann somit nicht erfolgen. Die genetische Differenzierung der adulten Baumpopulationen war gering (FST = 0.026). Der Großteil ihrer Variation (~ 97 %) lag innerhalb der Populationen, was intensiven Genfluss in der Vergangenheit widerspiegelt. Die genetische Differenzierung der Keimlinge war etwas erhöht (FST = 0.086) und ~ 91 % ihrer Variation lag innerhalb der Populationen. Im Gegensatz zu den adulten Bäumen konnte ich für Keimlinge ein „Isolation-by-distance“-Muster feststellen. Somit sind erste Hinweise auf begrenzten Genfluss im Keimlingsstadium infolge von Fragmentierung gegeben. Obwohl die Momentaufnahmen im Freiland keine Abnahme in der Frugivorenzahl und Samenausbreitung von P. africana als Folge von Fragmentierung beobachten ließen, weisen die Ergebnisse der genetischen Studie auf einen bereits reduzierten Genaustausch zwischen den Populationen hin. Somit lässt sich feststellen, dass die Faktoren Fragmentierung und Störung genetische Diversität, ökologische Prozesse und Artendiversität in Wäldern jeweils auf unterschiedliche Weise beeinflussen. Um Konsequenzen derartiger Einflüsse folgerichtig abschätzen zu können, sind Studien auf unterschiedlichen Diversitätsebenen unabdingbar.

Genetic dynamics across early life stages in the tropical tree Prunus africana (Rosaceae)

In many plant species, the genetic template of early life-stages is formed by animal-mediated pollination and seed dispersal and has profound impact on further recruitment and population dynamics. Understanding the impact of pollination and seed dispersal on genetic patterns is a central issue in plant population biology. In my thesis, I investigated (i) contemporary dispersal and gene flow distances as well as (ii) genetic diversity and spatial genetic structure (SGS) across subsequent recruitment stages in a population of the animal-pollinated and dispersed tree Prunus africana in Kakamega Forest, West Kenya. Using microsatellite markers and parentage analyses, I inferred distances of pollen dispersal (father-to-mother), seed dispersal/maternal gene flow (mother-to-offspring) as well as paternal gene flow (father-to-offspring) for four early life stages of the species (seeds and fruits, current year seedlings, seedlings ≤ 3yr, seedlings > 3yr). Distances of pollen and seed dispersal as well as paternal gene flow were significantly shorter than expected from the spatial arrangement of trees and sampling plots. They were not affected by the density of conspecific trees in the surrounding. At the propagule stage, mean pollen dispersal distances were considerably (23-fold) longer than seed dispersal distances, and paternal gene flow distances exceeded maternal gene flow by a factor of 25. Seed dispersal distances were remarkably restricted, potentially leading to a strong initial SGS. The initial genetic template created by pollination and seed dispersal was extensively altered during later recruitment stages. Potential Janzen-Connell effects led to markedly increasing distances between offspring and both parental trees in older life stages. This showed that distance and density-dependent mortality factors are not exclusively related to the mother tree, but also to the father. Across subsequent recruitment stages, the pollen to seed dispersal ratio and the paternal to maternal gene flow ratio dropped to 2.1 and 3.4, respectively, in seedlings > 3yr. The relative changes in effective pollen dispersal, seed dispersal, and paternal gene flow distances across recruitment stages elucidate the mechanisms affecting the contribution of the two processes pollen and seed dispersal to overall gene flow. Using the same six microsatellite loci, I analyzed genetic diversity and SGS across five life stages, from seed rain to adults. Levels of genetic diversity within the studied P. africana population were comparable to other Prunus species and did not vary across life stages. In congruence with the short seed dispersal distances, I found significant SGS in all life stages. SGS decreased from seed and early seedling stages to older juvenile stages, and it was higher in adults than in late juveniles of the next generation. A comparison of the data with direct assessments of contemporary gene flow patterns indicate that distance- or density-dependent mortality, potentially due to Janzen-Connell effects, led to the initial decrease in SGS. Intergeneration variation in SGS could have been driven by variation in demographic processes, the effect of overlapping generations, and local selection processes. Overall, my study showed that complex sequential processes during recruitment contribute to the spatial genetic structure of tree populations. It highlights the importance of a multistage perspective for a comprehensive understanding of the impact of animal-mediated pollen and seed dispersal on spatial population dynamics and genetic patterns of trees.

Prunus Petzoldi C. Koch

J. Goeschke

Eine durch Kreuzung erzielte Samenkapsel von Vanda gigantea Lindl.

von Christian Koopmann

Senecio Farfugium C. Koch (Farfugium grande Lindl.) : Eine neue bunte Blattpflanze

Vom Professor Dr. Karl Koch

Himantophyllum cyrthanthiflorum Lindl. msc. : Ein neuer Amaryllideen-Blendling

anonym