Pollination in Araucaria Juss

Haines, R. J.; Prakash, N; Nikles, D. G.

doi:10.1071/bt9840583

Cited by 31 publications

(11 citation statements)

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“…A posição erétil dos cones femininos de araucária nas extremidades dos ramos permite que a polinização seja mais eficiente, pois o grão de pólen pode cair com mais facilidade entre as escamas e mais próxima da micrópila. Esta característica também foi observada e descrita por Haines et al (1984) para outras espécies da família Araucariaceae. A fertilização em A. angustifolia ocorre aproximadamente um ano depois da polinização (Burlinghame 1914, Shimoya 1962) e coincide com o início do rápido crescimento dos cones femininos, verificado neste estudo.…”

Section: Discussionunclassified

Fenologia reprodutiva e produção de sementes em Araucaria angustifolia (Bert.) O. Kuntze

2004

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-(Reproductive phenology and seed production of Araucaria angustifolia (Bert.) O. Kuntze). The knowledge about the reproductive phenology of Araucaria angustifolia has applications to the seed harvest for "ex situ" conservation, for commercial use of the seeds and to understand the dynamic and regeneration of its natural populations. The reproductive phenology and seed production of A. angustifolia were evaluated for a natural population occurring at Parque Estadual Campos de Jordão, São Paulo State, Brazil. The present study investigates: (i) how is the reproductive cycle and the phenological pattern of araucaria? (ii) how is the potential of seed production and its variability? Sixty adult plants (30 males and 30 females) were marked for phenological observations. Seed production was estimated based on the number of female plants in a 10 ha area, number of cones per plant, number of seeds per cone and seed weight. The reproductive cycle of A. angustifolia extended for 20 to 24 months, from the observation of the first cone to seed fall. The pollination occurred between September and October and seed maturation and seed fall from March to June. Seed production was significantly different between years (117 kg.ha -1 in 2001 e 160 kg.ha -1 in 2002). The duration of ripe seed offer was also different between years. The variation observed in the amount and availability of seeds suggests that the observation of reproductive phenology and estimation of seed production are important to guide strategies for conservation and management of this resource.Key words -Araucaria angustifolia, Araucaria forest, reproductive phenology, seed production RESUMO -(Fenologia reprodutiva e produção de sementes em Araucaria angustifolia (Bert.) O. Kuntze). O estudo da fenologia reprodutiva de A. angustifolia tem aplicação na coleta de sementes destinadas à conservação de germoplasma, à obtenção de sementes para fins comerciais e ao entendimento da dinâmica de regeneração das populações naturais. Este trabalho teve como objetivo investigar a fenologia reprodutiva em uma população natural de A. angustifolia localizada no Parque Estadual Campos do Jordão, SP, procurando entender: (i) Qual é o seu ciclo reprodutivo e o comportamento fenológico? (ii) Como varia e qual o potencial de produção de sementes desta espécie? Para o acompanhamento da fenologia reprodutiva foram marcados 60 indivíduos (30 masculinos e 30 femininos), observados de novembro de1999 a agosto de 2002. A produção de sementes foi estimada com base na contagem do número de plantas femininas, número de estróbilos por planta, número de sementes por estróbilo e peso de sementes. O ciclo reprodutivo da A. angustifolia foi de 20 a 24 meses, do aparecimento dos estróbilos até a queda das sementes. A polinização ocorreu entre setembro e outubro e a maturação e queda das sementes de março a junho. A produção de sementes mostrou diferença significativa entre os anos (117 kg.ha -1 em 2001 e 160 kg.ha -1 em 2002) e a duração da oferta foi distinta entre anos. As variações na...

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Section: Discussionunclassified

Fenologia reprodutiva e produção de sementes em Araucaria angustifolia (Bert.) O. Kuntze

2004

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“…The pollination drop mechanism is present in gymnospermous plants, and examples have been documented from extinct seed ferns, extant conifers (Haines et al, 1984), cycads (Norstog and NichoUs, 1997), gnetophytes (Church, 1914;Bino et al, 1984;Kato and Inoue, 1994), and Ginkgo (Dogra, 1964). These seed plants are characterized by ovules, either borne singly, in strobili, or other clustered arrangements, that bear a terminal, projecting beak typically at the ovular pole opposite to the attachment site.…”

Section: Plants: Sources Of Rewards For Insectsmentioning

confidence: 99%

The Paleobiology of Pollination and its Precursors

Labandeira

2000

Paleontol. Soc. pap.

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Perhaps the most conspicuous of associations between insects and plants is pollination. Pollinating insects are typically the first and most obvious of interactions between insects and plants when one encounters a montane meadow or a tropical woodland. The complex ecological structure of insect pollinators and their host plants is a central focus within the ever-expanding discipline of plant-insect interactions. The relationships between plants and insects have provided the empirical documentation of many case-studies that have resulted in the formulation of biological principles and construction of theoretical models, such as the role of foraging strategy on optimal plant-resource use, the advantages of specialized versus generalized host preferences as viable feeding strategies, and whether “pollination syndromes” are meaningful descriptions that relate flower type to insect mouthpart structure and behavior (Roubik, 1989; Ollerton, 1996; Waser et al., 1996; Johnson and Steiner, 2000). Much of the recent extensive discussion of plant-insect associations has centered on understanding the origin, maintenance, and evolutionary change in plant/pollinator associations at ecological time scales and increasingly at longer-term macroevolutionary time intervals (Armbruster, 1992; Pellmyr and Leebens-Mack, 1999). Such classical plant-insect association studies—cycads and cycad weevils, figs and fig wasps, and yuccas and yucca moths—were explored at modern time scales and currently are being examined through a long-term geologic component that involves colonization models based on cladogenetic events of plant and insect associates, buttressed by the fossil record (Farrell, 1998; Pellmyr and Leebens-Mack, 1999; A. Herre,pers. comm.). In addition to tracing modern pollination to the earlier Cenozoic and later Mesozoic, there is a resurgence in understanding the evolutionary history of earlier palynivore taxa (spore, prepollen and pollen consumers), which led toward pollination as a mutualism (Scott et al., 1992).

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“…In most conifers pollen tubes reach the megagametophyte at or near the neck cells, grow over the surface of the megaspore wall and penetrate it just above the neck cells where the megaspore wall may be thin (Singh, 1978). In a few conifers, pollen tubes reach the megagametophyte some distance from the archegonia then grow a considerable distance over the megaspore wall to the archegonia (Doyle, 1945;Haines, Prakash, and Nikles, 1984;Colangeli and Owens, 1989). Douglas fir follows the first pattern but the megaspore wall is not thinner in the archegonial region, and the pollen tube may penetrate the wall near the archegonial chamber then grow beneath the wall to the archegonial chamber.…”

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confidence: 99%

Cytological Basis for Cytoplasmic Inheritance in Pseudotsuga Menziesii. I. Pollen Tube and Archegonial Development

Owens

Morris

1990

American J of Botany

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Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) ovules were used to study the method of pollen tube formation and penetration of the nucellus, the movement of the body cell down the pollen tube and development of the archegonia. No pollination drop forms but nucellar tip cells produce a minute secretion that may initiate pollen tube formation. Pollen tubes penetrate the nucellus causing degeneration of nucellar cells in contact with the pollen tube tip. The body cell becomes highly lobed and the tube cytoplasm forms thin sheets between the lobes. This may be the mechanism by which the large body cell is pulled down the narrow pollen tube. Body cell plastids and mitochondria remain unaltered during pollen tube growth, whereas tube cell organelles show signs of degeneration. The pollen tube penetrates the megaspore wall and settles in the archegonial chamber. During pollen elongation and pollen tube growth the egg matured. Egg cell plastids were transformed into large inclusions which filled the periphery of the egg while mitochondria migrated to the perinuclear zone. The neck cells, ventral canal cell and archegonial jacket cells are described. The significance of the body cell and egg cell ultrastructure is discussed in light of recent restriction fragment length polymorphism studies of plastid and mitochondrial inheritance in the Pinaceae.

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Pollination in Araucaria Juss

Cited by 31 publications

References 8 publications

Fenologia reprodutiva e produção de sementes em Araucaria angustifolia (Bert.) O. Kuntze

Fenologia reprodutiva e produção de sementes em Araucaria angustifolia (Bert.) O. Kuntze

The Paleobiology of Pollination and its Precursors

Cytological Basis for Cytoplasmic Inheritance in Pseudotsuga Menziesii. I. Pollen Tube and Archegonial Development

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