File:Fucus (106677927).jpg
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Summary
editDescriptionFucus (106677927).jpg |
prepared slide demonstration, x.s. of conceptacle with oogonia and antheridia Known also as wracks, the Fucus brown seaweeds are always diploid and meiosis takes place before the gametes are formed. The reproductive organs of the macroalgae consist of receptacles and conceptacles. Gamete production takes place in specialized crypt-like structures known as conceptacles. The conceptacles are carried in receptacles, which are swollen areas found at the tips of the plants. While some species of wracks are dioecious, others feature both types of sexual organs on one plant and are classified as monoecious. To add to the diversity of reproductive strategy featured by this genus of brown algae, some of the monoecious species have both sexes in a single conceptacle while others contain them in separate organs. The conceptacles for the male reproductive organs are lined with antheridiophores, which are branched and feature inflated, terminal antheridia on their branches. The antheridia are the sites of meiosis, forming 64 to 128 biflagellated male gametes that are referred to as antherozoids. The male and female gametes are usually released into the water during a rising tide with the female eggs emitting a potent volatile hydrocarbon compound (fucoserraten), which acts as an attractant for the mobile male antherozoids. The fertilized egg settles onto the sediment and germinates as a new diploid thallus. Known also as the medicinal seaweed or Fucus, species in this genus have the highest antioxidant activity of the edible seaweeds, most likely because of the fucoxanthin. As an extract, it is available as a dietary supplement and supports a thriving industry along Ireland's coasts. Brown algae, particularly members of this genus, are especially rich in iodine and including it in the diet is thought to possibly remedy some thyroid problems. In Japan, F. vesiculosus, easily recognized by its paired air bladders, is also used as a dietary preventative of breast cancer and reportedly reduces cholesterol levels and enhances the immune system. -Cynthia D. Kelly, Thomas J. Fellers and Michael W. Davidson |
Date | |
Source | Fucus |
Author | JJ |
Camera location | 38° 32′ 23.91″ N, 121° 45′ 30.8″ W | View this and other nearby images on: OpenStreetMap | 38.539975; -121.758556 |
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This image was originally posted to Flickr by JJT1982 at https://flickr.com/photos/34838312@N00/106677927 (archive). It was reviewed on 4 December 2018 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
4 December 2018
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current | 18:44, 4 December 2018 | 2,592 × 1,944 (2.32 MB) | Luisbrudna (talk | contribs) | Transferred from Flickr via #flickr2commons |
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Metadata
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Camera manufacturer | Canon |
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Camera model | Canon PowerShot SD400 |
Exposure time | 1/25 sec (0.04) |
F-number | f/4.5 |
Date and time of data generation | 16:06, 1 March 2006 |
Lens focal length | 14.421 mm |
Orientation | Normal |
Horizontal resolution | 180 dpi |
Vertical resolution | 180 dpi |
File change date and time | 16:06, 1 March 2006 |
Y and C positioning | Centered |
Exif version | 2.2 |
Date and time of digitizing | 16:06, 1 March 2006 |
Meaning of each component |
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Image compression mode | 5 |
APEX shutter speed | 4.65625 |
APEX aperture | 4.34375 |
APEX exposure bias | 0 |
Maximum land aperture | 4.34375 APEX (f/4.51) |
Metering mode | Pattern |
Flash | Flash did not fire, compulsory flash suppression |
Supported Flashpix version | 1 |
Color space | sRGB |
Focal plane X resolution | 11,520 |
Focal plane Y resolution | 11,571.428571429 |
Focal plane resolution unit | inches |
Sensing method | One-chip color area sensor |
File source | Digital still camera |
Custom image processing | Normal process |
Exposure mode | Auto exposure |
White balance | Auto white balance |
Digital zoom ratio | 1 |
Scene capture type | Standard |