Male and Female Pollination Success in a Deceptive Orchid, a Selection Study

Ecology ◽  
1998 ◽  
Vol 79 (4) ◽  
pp. 1246 ◽  
Author(s):  
Lisa M. O'Connell ◽  
Mark O. Johnston
Keyword(s):  
Male And Female ◽  
Pollination Success

scholarly journals Sexual ratio and floral biology of the dioecious Neea theifera Oerst. (Nyctaginaceae) in a cerrado rupestre of central Brazil

2011 ◽  
Vol 25 (4) ◽  
pp. 785-792 ◽  
Author(s):  
Felipe Wanderley Amorim ◽  
Clesnan Mendes-Rodrigues ◽  
Pietro Kiyoshi Maruyama ◽  
Paulo Eugênio Oliveira
Keyword(s):  
Resource Allocation ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Reproductive Strategy ◽  
Pollen Viability ◽  
Floral Biology ◽  
Pollinator Limitation ◽  
Dioecious Species ◽  
Male And Female ◽  
Pollination Success

Dioecy is characterized by a complete separation of sexual functions on male and female plants. It has evolved many times in flowering plants and is widespread among distinct Angiosperm families. It is viewed as a reproductive strategy to reduce endogamy, and to promote optimal resource allocation between male and female sexual functions. Neea theifera is a common species in Cerrado, neotropical savannas in Brazil, but information regarding its reproductive biology is still incomplete. In order to investigate how environmental conditions possibly affect this dioecious species, we studied its floral biology, sex ratio and spatial distribution of sexual morphs along a soil-altitudinal gradient. The sex ratio did not significantly deviate from the expected 1:1 ratio. However, flower abundance in the population was significantly biased towards staminate flowers. Female individuals were larger than male individuals and plant size was negatively correlated with altitude, but did not differ between sexual morphs. The population did not show spatial segregation of sexes and male individuals were sexually mature earlier than female ones. Staminate flowers were larger than pistillate flowers and presented high pollen viability. Meliponini bees, small flies and thrips were potential pollinators, but pollination success was very low. Dioecy in N. theifera corroborates many general features of this reproductive strategy, such as woody habit, inconspicuous flowers, pollination by small generalist insects and differential resource allocation between male and female plants. However, reproduction in this species seems to be impaired by pollinator limitation. The results showed that the soil-altitude gradient influenced the growth pattern of the species and may play an important role in its reproductive biology but did not affect dioecy directly.

Effect of nectar supplementation on male and female components of pollination success in the deceptive orchid Dactylorhiza sambucina

2008 ◽  
Vol 33 (3) ◽  
pp. 300-306 ◽  
Author(s):  
Jana Jersáková ◽  
Steven D. Johnson ◽  
Pavel Kindlmann ◽  
Anne-Charlotte Pupin
Keyword(s):  
Male And Female ◽  
Pollination Success ◽  
Dactylorhiza Sambucina

FORAGING BEHAVIOUR OF HONEY BEES (APIS MELLIFERA L.) ON STAGHORN SUMAC [RHUS HIRTA SUDWORTH (EX-TYPHINA L.)]: DIFFERENCES AND DIOECY

1996 ◽  
Vol 128 (3) ◽  
pp. 355-366 ◽  
Author(s):  
Carlos F. Greco ◽  
Dean Holland ◽  
Peter G. Kevan
Keyword(s):  
Apis Mellifera ◽  
Reproductive Success ◽  
Honey Bees ◽  
Foraging Behaviour ◽  
Anther Dehiscence ◽  
Male And Female ◽  
Pollination Success ◽  
Pollen Loads ◽  
Natural Stands ◽  
Foraging Pattern

AbstractThe foraging behaviour of honey bees (Apis mellifera L.) on inflorescences of staghorn sumac [Rhus hirta Sudworth (ex-typhina L.)] was studied using a “choice table” placed in natural stands of this plant. The choice table consisted of a wooden grid with alternated male and female inflorescences of sumac. Honey bee activity was recorded also on inflorescences of naturally growing plants in which the secretion of nectar was measured and the anther dehiscence recorded. Honey bees were the only common pollinators observed on sumac in the study area. During the morning, both plant sexes secreted little nectar, and pollen was available after the dehiscence of the anthers which took place between 1000 and 1100 hours. Female inflorescences secreted great amounts of nectar during the afternoon, but in male inflorescences there was little secretion. Honey bees seemed to forage according to the circadian availability of resources. Most of their activity concentrated on male inflorescences in the morning and on female ones during the afternoon. Both the occurrence of bees with pollen loads in their corbiculae and the length of the visits to each sex also seemed to be in accordance to the kind of resource exploited at particular times of the day. Most of the bees with pollen loads were observed during the morning and the longest visits to any inflorescences were registered on female ones during the afternoon (by bees foraging for nectar). Despite our results suggesting that the pollination success of staghorn sumac would be impaired by the foraging pattern of honey bees, an explanation is proposed for its reproductive success.

MALE AND FEMALE POLLINATION SUCCESS IN A DECEPTIVE ORCHID, A SELECTION STUDY

Ecology ◽  
1998 ◽  
Vol 79 (4) ◽  
pp. 1246-1260 ◽  
Author(s):  
Lisa M. O’Connell ◽  
Mark O. Johnston
Keyword(s):  
Male And Female ◽  
Pollination Success

The Clinical, Roentgenological and Morphological Effects of an Acute Exposure of Phosgene on the Lungs of Dogs

1971 ◽  
Vol 29 ◽  
pp. 236-237
Author(s):  
R. F. Bils ◽  
W. F. Diller ◽  
F. Huth
Keyword(s):  
Latent Period ◽  
Chemical Industry ◽  
Toxic Substance ◽  
Lung Edema ◽  
X Rays ◽  
Beagle Dogs ◽  
Male And Female ◽  
Morphological Alterations ◽  
Before And After ◽  
Electron Microscopes

Phosgene still plays an important role as a toxic substance in the chemical industry. Thiess (1968) recently reported observations on numerous cases of phosgene poisoning. A serious difficulty in the clinical handling of phosgene poisoning cases is a relatively long latent period, up to 12 hours, with no obvious signs of severity. At about 12 hours heavy lung edema appears suddenly, however changes can be seen in routine X-rays taken after only a few hours' exposure (Diller et al., 1969). This study was undertaken to correlate these early changes seen by the roengenologist with morphological alterations in the lungs seen in the'light and electron microscopes.Forty-two adult male and female Beagle dogs were selected for these exposure experiments. Treated animals were exposed to 94.5-107-5 ppm phosgene for 10 min. in a 15 m3 chamber. Roentgenograms were made of the thorax of each animal before and after exposure, up to 24 hrs.

Ultrastructural investigation of spontaneous pituitary gonadotroph cell adenomas in aging Sprague-Dawley rats

1983 ◽  
Vol 41 ◽  
pp. 702-703
Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Epoxy Resin ◽  
Immunoelectron Microscopy ◽  
Tumor Type ◽  
Gonadal Function ◽  
Sprague Dawley ◽  
Male And Female ◽  
Reticulin Fibers ◽  
Sprague Dawley Rats

Gonadotroph cell adenomas of the pituitary are infrequent in human patients and are not invariably associated with altered gonadal function. To date, no animal model of this tumor type exists. Herein, we describe spontaneous gonadotroph cell adenomas in old male and female Sprague-Dawley rats by histology, immunocytology and electron microscopy.The material consisted of the pituitaries of 27 male and 38 female Sprague Dawley rats, all 26 months of age or older, removed at routine autopsy. Sections of formal in-fixed, paraffin-embedded tissue were stained with hematoxylin-phloxine-saffron (HPS), the PAS method and the Gordon-Sweet technique for the demonstration of reticulin fibers. For immunostaining, sections were exposed to anti-rat β-LH, anti-ratβ-TSH, anti-rat PRL, anti-rat GH and anti-rat ACTH 1-39. For electron microscopy, tissue was fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4 and embedded in epoxy-resin. Tissue fixed in 10% formalin, embedded in epoxy resin without osmification, was used for immunoelectron microscopy.

Quantitative ultrastructural reconstruction of small regions within large volumes by correlative light and high voltage electron microscopy of serial 0.25-0.50 μm sections

1987 ◽  
Vol 45 ◽  
pp. 578-581
Author(s):  
Conly L. Rieder ◽  
Frederick J. Miller ◽  
Edwin Davison ◽  
Samuel S. Bowser ◽  
Kirsten Lewis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Mitotic Spindle ◽  
Meiotic Spindle ◽  
High Voltage Electron Microscopy ◽  
Male And Female ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Differential Stability ◽  
Sperm Aster

In this abstract we Illustrate how same-section correlative light and high voltage electron microscopy (HVEM) of serial 0.25-0.50-μm sections can answer questions which are difficult to approach by EM of 60-100 nm sections.Starfish (Pisaster and Asterlas) eggs are fertilized at meiosis I when the oocyte contains two maternal centrosomes (e.g., asters) which form the poles of the first meiotic spindle. Immediately after fertilization a sperm aster is assembled in the vicinity of the male pronucleus and persists throughout meiosis. At syngamy the sperm aster splits to form the poles of the first mitotic spindle. During this time the functional and replicative properties of the maternal centrosome, inherited from the last meiotic division, are lost. The basis for this differential stability, of male and female centrosomes in the same cytoplasm, is a mystery.

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