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 Seed Dispersal

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PostSubject: Seed Dispersal   Wed Sep 22, 2010 11:47 am

After fertilisation the seeds are attached to the parent plant. These seeds need to be dispersed away from the parent plant and others to reduce competition for resources such as light energy and water. Your task for this forum is to investigate the variety of different ways in which plants are able to disperse their seeds.

1) Please read pages 192-193 ´Dispersal of seeds and fruits´for background information on this topic.

2) Watch the video below about some interesting ways in which seeds are dispersed.

3) Research on the internet to find one interesting example of seed dispersal. You must attach a picture of the seed and also write a summary of at least 150 words about its stucture and method of dispersal. You may include some other interesting information about the seed also.


IMPORTANT: You must not choose a seed from the textbook or the video. You must not choose a seed which your classmate has already chosen and added to the forum!!!


DUE DATE: You must post your forum by the start of your second class during Week 29 (11/10/10)


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renata diuana



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PostSubject: Seed Dispersal   Tue Oct 12, 2010 5:38 pm

Seed Dispersal
Is the movement and and transport of seeds away from parent plant. Because of their limited mobility they usually rely of diferent factors, such us wind, water, animals, etc. The seeds once dropped are dispersed around the ground or moved into other flowers. With this process plants and flowers grow.

Seed dispersal- Drop and Roll in Chestnut
-Seeds are enclosed in a “case”. When they fall from the tree the casing breaks and the seed is relesed away from the tree.


Seed dispersal- Wind dispersal of seeds
Small and light in order to be carried away by the wind. Seed adaptations make the seed stay in the air for longger or help them to be released. This adaptations make the seeds travell longger distances.
- Pepper-pot type
The flower`s ovary cantains seeds. It becomes then a dry hollow with more openings. The containers shaken by the wind, making the seeds fall through the openings. When they fall they are dispersed around the area.

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Nicolas Delorenzo



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PostSubject: Re: Seed Dispersal   Tue Oct 12, 2010 9:02 pm

Seed dispersal of the almond

The almond is the seed of the tree called by the same name. The seed has a thin cover and we as humans eat it. This seed can be dispersed in several ways:

1) By wind: This happens naturally when the wind blows out an almond from the tree were its hanging, here the seed often falls to the ground near the tree because the wind doesn’t have the strength to blow the seed so far.

2) By water: This case is very rare and only occurs when the tree is near a river. It happens when the seed falls into the river and deposit on another part were the river leaves it. Most of the time the seed end far apart the tree and near the river were it had came from.

3) By animals:
This happens though ingestion. This means the animal eats the seed and afterward it throws it away as waste and the seed get out. By this way of dispersal the seed can be placed near or away from the original tree, it depends were the animal leaves his wastes, but what is most common is that the seed is placed far apart from the tree.



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Martino Egidio



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PostSubject: Seed Dispersal   Tue Oct 12, 2010 10:37 pm

Explosive seed dispersal

Seed dispersal is very important for the continuality of plants. When seeds do not disperse and fall very near the plant, those plants will grow very near and this will be bad for them, because they will have to share nutrients. But if seeds are dispersed, plants may grow alone and not share essential nutrients.

One of the many methods of seed dispersal is the explosive seed dispersal also called Ballistic dispersal. This consists in an explosive discharge of seeds from the fruit. the seeds are ejected from the fruit by elastic contraction of the tissue. Fruits are shaped in the way so that they are flunged away from the "parent plant". This method does not achieve a lot of distance such as the animal dispersal, but many ballisitic dispersed seeds have another way in which seeds are dispersed futher away.

One example of this type of seed is Leguminosea, which produces seed pods that dry in the sun. In the pods walls there is tension as the pod dries and this tension eventually causes the pod to split along two lines of weakness. As the two halves curls back, the seeds suddenly burst and they are flunged away in an explive manner.
In this picture we can see the halves of the seed pod clearly twisted, and the whole pod which is entire.



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Oscar Leria



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PostSubject: Squirting Cucumber (Cucurbitaceae)   Wed Oct 13, 2010 5:34 pm

Ballistic seed dispersal, or autochory, is the physical and often explosive discharge of seeds from the fruit. The seeds are typically ejected from the fruit by elastic contraction of the fruit tissues and often the fruits are shaped such that seeds are flung away from the parent plant. Ballistic dispersal does not often achieve the same distance as animal-dispersed seeds.

Squirting cucumbers discharge their seeds in a mucilaginous stream of liquid.

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isabella st.



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PostSubject: Mangrove seed dispersal   Wed Oct 13, 2010 7:19 pm

Many aquatic and some ground plants use hydrochory (seed dispersal through water). Using this method seeds can travel very long distances depending on the type or mode of water dispersal.

Mangrove trees live right in or next to the water. Their seeds fall from the tree and grow roots as soon as they touch any kind of soil. During low tide, they might fall in soil instead of water and start growing right where they fell. If the water level is high, however, they can be carried far away from where they fell. Mangrove trees often make little islands as dirt and other things collect in their roots, making little bodies of land.

Mangrove seeds float and so are suited best for water dispersal. Unlilke most plants, some mangroves have seeds that can germinate while still attached to the 'parent' tree. When the seed is germinated, the seeding grows either inside the fruit or out through the fruit to form a propagule (ready to go seeding), which produces it's own food through photosynthesis. Once the propagule is mature it drops into the water where it can be transported great distances. Propagules may remain dormant for more than a year before reaching a suitable environment in which to develop. When the propagule is ready to root,it changes density so that it floats vertically rather than horizontally so that it is more probable for it to lodge in the soil.If it doesn't root it changes density again and floats away looking for better conditions.


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fernanda valiente



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PostSubject: Re: Seed Dispersal   Wed Oct 13, 2010 7:51 pm

Seed Dispersal:

1. By wind: wind dispersal can take on one of two primary forms: seeds can float on the breeze or alternatively, they can flutter to the ground. Some tall trees produce seeds with stiff wings covering the seed that enable them to fly long distances. The wings are twisted and balanced so that the seed spins around as it is carried along by the wind. These natural adaptations for using the wind to transport the weight of the seed must be technically accurate, as the wings of modern planes and helicopters are designed in the same way.

2. By water: seeds can travel for extremely long distances, depending on the specific mode of water dispersal. Although seeds of plants that grow in water are obviously spread by water, there are many other ways in which water plays a part in dispersing seeds. Plants which grow beside water often rely on water to transport their seeds for them. They may produce light seeds which float, or there may be fluff that helps buoyancy.

3. By animals: seeds can be transported on the outside of vertebrate animals (mostly mammals), a process known as epizoochory. Plant species transported externally by animals can have a variety of adaptations for dispersal, including adhesive mucus, and a variety of hooks, spines and barbs. Seeds with attractive fruit or seeds.To attract the animals and birds and encourage them to act as seed carriers, plants often surround their seeds with a brightly-coloured and sweet-tasting pulp.

Example seed dispersal by wind:
the part of an individual disk or ray floret surrounding the base of the corolla, equivalent to the calyx of a non-compound flower. The pappus may be like bristles or tiny hairs, teeth, or scales, and can be too small to see without magnification.

PD: sorry i can't put a pic.
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Anto Rodriguez



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PostSubject: Burdocks   Wed Oct 13, 2010 7:56 pm

Seed Dispersal

Seed dispersal is the movement or transport of seeds away from the parent plant so then the plant can expand or spread its range when a seed is carried to a new environment suitable for growth.

Seed Dispersal in Burdocks

Burdocks are wild and hardy plants that have long and dark roots which is highly valuable in macrobiotic cooking for its strengthening qualities. The seeds are dispersed by generally sticking themselves to animals or living things in the environment.

The prickly heads of these plants (burrs) are noted for easily catching on to fur and clothing; this provides an excellent mechanism for seed dispersal. Burrs cause local irritation and can possibly cause intestinal hairballs in pets. However, most animals avoid ingesting these plants.



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fernando orrego



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PostSubject: seed dispersal   Wed Oct 13, 2010 8:09 pm

Seeds that grow too near to their parent plants, have to compete with the parent plants for food, light and space. Seeds therefore need to be spread away from the parent plant if they are to avoid this competition, and grow into well developed and healthy new plants.

The spreading around of plant seeds is commonly referred to as dispersal.

Modes of Seed Dispersal:

There are a number of modes or ways by which seeds may be dispersed, these include:

Wind dispersal
Water dispersal
Animal dispersal
Mechanical dispersal

Dispersal mechanism of plants in the desert

Dispersal by the wind
Some plants have wind-dispersed seeds, which are occasionally blown many miles from their origins. This means of dispersal is common among pioneer plants (plants that are adapted to colonizing disturbed habitats). Because of their superior ability to invade newly-disturbed ground, pioneer plants comprise many of our agricultural and garden weeds. Moreover, most annual crops are domesticated pioneer plants. That’s why we need to plow (disturb) fields in order to grow them.

Dispersal by animals
Many plants use animals to disperse their seeds in another complex coevolutionary process. Small, brightly-colored fruits such as hackberry and boxthorn are offered as food for birds that swallow them whole. Other fruits such as those of hedgehog cacti are large and birds feed on them repeatedly. Some bird fruits are sticky, such as mistletoe berries; a few stick to the bird’s bill until wiped off on a branch while others are successfully swallowed. The seeds of bird fruits are typically small and hard; they pass through birds’ guts undamaged and may be deposited many miles from the parent plant.

Dispersal by water
Even in the desert some seeds are water-dispersed. Blue palo verde (Cercidium floridum) grows mostly along washes. Flash floods disperse the very hard, waterproof seeds downstream, scarifying (abrading the surface of) them in the process. In the absence of scarification these seeds must weather in the ground for a few years before the seed coats become permeable and permit germination.
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Nico Aveta 7



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PostSubject: Re: Seed Dispersal   Wed Oct 13, 2010 8:18 pm

Milkweeds, also known as Asclepias, are a type of plant which has over 140 different species. Asclepias were name by Carl Linnaeus after the greek god of healing, Asclepius, becasue there were many folk-medicinal uses for this plant. They are an important source of nectar for bees and many nectar-seeking insects. Some species are know to be toxic.

Pollination in milkweeds happen in a very unusual way. Pollen is grouped in very complex structures called Pollinia (or pollen sacs), rather that the typical way which is in individual grains. Feet or mouthparts insects such as bees, wasps and butterflies slips in between the pollen sacs and the base of them are mechanically attached to the insects, taking some pollen sacs with them.

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SRojas



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PostSubject: Seed Dispersal   Wed Oct 13, 2010 8:37 pm

There are many types of Seed Disposal. This seed disposal is often called Myrmecochory, or seed dispersal by ants.
Plants like Trilliums disperse by the help of animals, or ants. The way this works is that the seeds are coated with something called Elaiosome, a fleshy body that is also basically ant food and very well attached to the seed. The ants find this Elaiosome body irresistible and drag the seed into their homes, or the colony of ants. When they take it down there, the ant is basically planting the seed on the ground and also protecting it from birds or any seed eating insects and birds from eating them. Also it is protecting it from forest fires that may burn the seed and later on may not be able to grow and germinate. After this, Trilliums have an approximate time of 5-9 years in order to reach a flowering age.


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Philip Black



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PostSubject: Tumbleweed or Russian thistle   Wed Oct 13, 2010 10:02 pm

Seed dispersal is important for all plants as it is key for the next plant to grow properly. This is because for the younger plant or seed to grow it needs all the essential elements, and if it is too near the mother or parent plant it will be sharing the nutrients needed and it will affect its growth.

There are many different forms of seed dispersal, and the most common ones are through water, air or through an animal. But this form is very rare and different and it occurs with only very few plants. The common tumbleweed was originally from Russia and Siberia but it was brought to america. One plant can produce 20 to 50 thousand seeds and as it falls it comes together with the other seeds and it is pushed by srtong gusts of wind. The tumbleweed moves across valleys and down hills as it drops all of its seeds on the way.







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sophie.esnouf



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PostSubject: Splitting suddenly - Shooting   Wed Oct 13, 2010 10:57 pm

Jewelweed has soft semi-succulent stems and leaves, and prefers shade to bright sunlight. They hang suspended from tiny ítems and grows in huge clusters in shady forested areas, particularly where it can find moist soil. You can recognize these clusters immediately by the smooth and almost luminous appearance of the jewelweed leaves, and by the uniformity of the foliage. Jewelweed clumps manage to grow so densely that they prevents other plants from growing around. Its common name (touch-me-not) comes from the way this plant disperses its seeds. The little hanging structures on the plant are its seedpods. After the pods have grown to maturity, when touched, they burst with a little pop.
Explosive dehiscence (spontaneous opening at maturity of a plant structure) ballistically disperses seeds in a number of plant species. During dehiscence, mechanical energy stored in specialized tissues is transferred to the seeds to increase their kinetic and potential energies. In this species the valves forming the seed pod wall store mechanical energy.
/Users/sophieesnouf/Desktop/jewelweed.jpg
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Joako Ruiseñor



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PostSubject: seeds   Wed Oct 13, 2010 11:13 pm

Parachute seeds
1.-Seeds with an elevated umbrella-like crown made of branched hairs at the top
2.-Similar dispersal systems as the dandelion
3.-the slightest gust of wind catches the branched hairs elevating the seed as a real parachute
4.-This seed is often produced in globose heads or puff-like clusters.
5.-belongs to the sunflower family (world's largest plant family with about 24,000 described species).
6.- Hundreds of parachute seeds (each with a tuft of silky hairs) are produced within large, inflated pods called follicles.
7.-Seeds get very far away from their parent plant in order to avoid competition. It is ñight so with a small gust of wind the seed can fly across valleys or mountain slopes.
8.-Seed dispersed by the wind agent.

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nati bruna



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PostSubject: passion fruit   Wed Oct 13, 2010 11:31 pm

passion fruit is natively grown in Paraguay, Brazil and Argentina, but it is also grown in many other countries. There are two types of this fruit:
-The bright yellow variety of passion fruit, which is also known as the Golden Passion Fruit, can grow up to the size of a grapefruit, has a smooth, glossy, light and airy rind, and has been used as a rootstock for the Purple Passion Fruit in Australia.
- The dark purple passion fruit is smaller than a lemon, though it is less acidic than the yellow passion fruit, and has a richer aroma and flavor. In Colombia, the purple passion fruit is referred to as "gulupa", to distinguish it from the yellow maracuya.
Passion fruit is dispersed by gravity. The effect of gravity on heavier fruits causes them to fall from the plant when ripe. Gravity dispersal also allows for later transmission by water or animal.
PD: i cant put images
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tomas-arce



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PostSubject: Re: Seed Dispersal   Thu Oct 14, 2010 4:41 pm

Seed Dispersal
Shakers

Some plants, like, Opium poppy, have a very special way of seed dispersal. The head of this plants (also known as poppy seed heads), after being dried by the sun, have little hloes all around their top (like pepper or salt shakers). These shake when it's windy and the tiny seeds are thrown out of the shaker the holes on the top of the plant.

Seed Dispersal by shaking can also occur with the help of an animal. For example, the African Elephant eats the Acacia plant and helps to disperse the seeds by shaking the trees. When the elephant eats the seeds, they find a fertile home in the elephant's droppings.



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Pedro Varela Silva



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PostSubject: [b]SEED DIPERSAL THROUGH FIRE[/b]   Thu Oct 14, 2010 5:47 pm

SEED DIPERSAL THROUGH FIRE

The way a plant stores its seeds and disperses them is an example of a fire adaptive strategy.
The intensity of the fire ( it is important the fire reaches the right temperature) is crucial to the seeds dispersal.
Also important is how often the fires occur.

A number of species of pine have cones that only open after a fire. These are called serotinus.
Jack pines have cones that are held closed by a resin sensitive to high temperatures.
These cones will not open to release their seeds until a critical temperature is reached.
Another type of pine called Lodgepole pine ( this is a western U.S. variety of tree) is both serotinus and free opening.



In some cases if fires are frequent and do not reach the correct temperature, the species will be killed and the seeds not dispersed
(the right heat is crucial to the seeds dispersal mechanism).

Some species store their seeds in the soil until a fire reaches the right heat for germination to be triggered.
Again if the fires are low intensity the parent plant may die but germination not triggered.
Fires are often deliberately lit in the bush to trigger germination from soil seed banks and to kill weeds.


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sebastian muñoz



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PostSubject: Re: Seed Dispersal   Thu Oct 14, 2010 7:04 pm

Seed Dispersal
Seed dispersal is the movement or transport of seeds away from the parent plant. There are some advantages of dispersing like competition; they reduce their competition by moving away from its tree. Another benefit of dispersing is that it ensures genetic variablity by separating male gametes with female gametes. There are different ways if dispersing:

-Water: Many aquatic plants and plants that live near water have seeds that can float, and are carried by water. Plants living along streams and rivers have seeds that float downstream, and therefore become germinate at new sites

-Animals: Animals disperse seeds in several ways. First, some plants, like the burr at left, have barbs or other structures that get tangled in animal fur or feathers, and are then carried to new sites. Other plants produce their seeds inside fleshy fruits that then get eaten be an animal.

-Wind: The kind of seeds which are often wind dispersed are smaller seeds that have wings or other hair-like or feather-like structures. Plants that produce wind blown seeds, often produce lots of seeds to ensure that some of the seeds are blown to areas where the seeds can germinate.

Seed Dispersal of a Kapok Tree
15cm pods containing seeds surrounded by a fluffly, pale yellowish fibre that resembles cotton. It has been used as a filling for pillows. So as the fibre is not so resistant or strong, this tree uses a combined method of seed dispersal. The pods split open to expose the fluffly cotton which then requires wind to dislodge them from the pods.

Sebastián Muñoz 1°F


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Matias Galilea



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PostSubject: Seed Dispersal by animals   Thu Oct 14, 2010 7:38 pm

Animals can disperse plant seeds in several ways:
-Seeds can be transported on the outside of vertebrate animals (mostly mammals), a process known as epizoochory. Plant species transported externally by animals can have a variety of adaptations for dispersal, including adhesive mucus, and a variety of hooks, spines and barbs. Luckily for the plant the animal will continue his path and will take the seeds away from the area. By shaking, bathing, or moving, the seeds will fall from the animal and grow where they fall.
-Also the seeds can be transported in the interior of the animal after he has eaten the fruit. Seed dispersal via ingestion by vertebrate animals (mostly birds and mammals), or endozoochory, is the dispersal mechanism for most tree species. The plant creates edible, nutritious fruit as a reward to frugivorous animals that consume it. Birds and mammals are the most important seed dispersers, but a wide variety of other animals, including turtles and fish, can transport viable seeds. The seeds contained in the interior of the fruit cannot be digested by the animals body, so when the animal goes to excrete far away from the parent plant, he excretes the seeds which later grow into another plant.

An example of a plant which disperses his seeds via the interior of an animal is the Blackberry.
The Blackberry creates the fruits which attract birds, the birds eat the fruit and also the seed, but they do not digest the seeds, when they excrete, they drop the seeds into the ground and another blackberry starts to develop. At leats in the south of Chile after eating the fruit, the birds go and stand on the fences of the plantation fields and excrete, and thats why there are always Blackberries besides the fences.

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pablo.cotera



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PostSubject: Eucalyptus Torelliana Seed Dispersion   Thu Oct 14, 2010 9:33 pm

Eucalyptus Torelliana Seed Dispersion

Seed dispersal is essential for the continuity of all tree and plant species, as it is the way that seeds produced by these get to somewhere suitable for their growing, and find another seed to start growing into a plant or tree.

Fruits of Eucalyptus torelliana produce resin which is collected by workers of the stingless bee Trigona Carbonaria. Seeds adhere to resin in the workers' corbiculate and are transported to the nest. Workers transport seeds distances of more than 300 m from the parent tree and seeds at the nest were viable and capable of germination. Seeds are removed from the nests by workers and discarded away from the nest, and Eucalyptus torelliana trees became established in the vicinity of colonies of Trigona carbonaria bees. Bees are the only invertibrates besides ants that help in a seed dispersal mechanism.
http://gislab.fiu.edu/treesofMiami/trees/images/Eucalyptus_torellianaFr.jpg

Pablo Cotera 1B
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Martina Cuevas



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PostSubject: Re: Seed Dispersal   Thu Oct 14, 2010 10:29 pm

Dandelions Seed Dispersal.
A dandelion is a flower, made up by really tiny flowers bunched together, it has a straw like stem which colour is green.
After it blooms, each of the tiny flowers produce a seed, everyone of this seeds it is attached to the stem with white fluffy threads.

Type of Dispersal
Dandelion seeds are carried away by the wind and travel like tiny parachutes.A strong wind can carry the parachutes miles away from the parent plant. The parachute process includes seed or achenes( one-seeded fruits), with puff-like clusters at the top. Then the slightest gust of wind catches the cluster, and shoots the seed up into the air like a parachute. This process it the most effective for dandelion seeds, as it has blown the seeds across mountain ranges,landed in open fields all across the western part of the USA.
Many types of seeds use wind dispersal since it the most common and useful






Martina Cuevas 1.D
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ileana correa



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PostSubject: Re: Seed Dispersal   Thu Oct 14, 2010 11:23 pm

Seed dispersal is the transport of the seed away from the parent.
It can be in different ways; wind, water or by animals. Every plant has its own characteristics for it to disperse its seeds.
An example of flower seed’s transported by insects or animals is the scarlet pimpernel.
This flower is very colorful (can be orange or purple). With these colors it attracts mostly Butterflies and bees. Its stamen is 65 mm outside from the level of the leaves so it can stick easily to animals, and in the middle it contains a sticky substance, that also attracts insects.

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ignacio molina



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PostSubject: Venus Flytrap   Sun Oct 17, 2010 1:06 pm

Venus Fly Traps come out of dormancy and start growing sometime in mid to late February. In early spring,
they put out traps that are low to the ground. As the days get longer and warmer, they start putting out
growth that stands up a little higher off the ground. Sometime in May they usually start growing a flower stalk.
The flower stalk will mature and produce several white flowers that bloom in July. When a Venus Fly Trap is
sending up its flower stalk, it usually stalls its growth a bit.
If the flowers are pollinated, the seed pods will dry out and the seeds will start to disperse sometime in
late July or early August. The seeds will germinate immediately if they fall on moist soil.
As summer progresses into fall, the growth of the Venus fly trap again starts to hug the ground. Also, the plant
starts getting better coloration. Sometime near the middle or end of October, as the days get shorter and cooler,
the plant starts to enter dormancy. During dormancy, the plant will not grow much if at all and it actually looks
mostly dead because many of the traps and leaves turn completely black.
Dormancy lasts until mid February and then the cycle starts again.

Plants can be propagated by seed, although seedlings take several years to mature. More commonly, they are
propagated by division in spring or summer.
Raising flytraps from seed is difficult, requiring patience and a lot of care. Tissue culture, leaf cuttings
(pulling entire leaf off), and bulb division are common methods of propagating
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tomas.silva



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PostSubject: Seed dispersal   Sun Oct 17, 2010 6:17 pm

Seed dispersal in Moth orchids:

The Moth Orchids disperse there seeds by attracting Moths into the plant ( known as a insect pollinated flower).
Many orchids use bright colours and strong scents to attract the insects. The Moth orchid has two long spurs and a long stalk.
The flower attracts the moths to the sticky spurs for getting the pollen all around the insects body.
The moth Orchids seeds have very small seeds so lots of seeds can stick into only one moth.

[url][/url]
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gregorio ingham



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PostSubject: Seed dipersal Ingham 1E   Mon Oct 18, 2010 5:12 pm

To make themselves space in the world, plants disperse their seeds. There are many ways they can do this,normally it is choosen the one most efficient in the environment. Some ways it can be dispersed are:
By wind: There are some fruits that adapted themselves to catch the wind and use it for their own benefit. For example the dandelion uses the wind to throw the seeds to a place far away.
By explosive mechanism: there are fruits that can function by its own. An important example will be the lupin a fruit that suddenly burst throwing their seeds in many directiones at the same time.
By water: Some seeds are resistable to water because they want to travel throw the water until reaching a straight land.
By animals: As many others, fruits are tasty to animals. This will make a easier travel for them because their eaten and not digested. This means no harm has been made to the seed, so the seed passes through the animal and thrown into any land with an extra fertiliser surrounding it.

Dandelion
The leaves are 5–25 cm long or longer, simple and basal, entire or lobed, forming a rosette above the central taproot. The flower heads are yellow to orange colored, and are open in the daytime but closed at night. The heads are borne singly on a hollow stem that rises 1–10 cm or more above the leaves and exudes a milky sap when broken. A rosette may produce several flowering stems at a time. The flower heads are 2–5 cm in diameter and consists entirely of ray florets. Each achene is attached to a pappus of fine hairs, which enable wind-aided dispersal over long distances.
The flower head is surrounded by sepals in two series. The inner sepals are erect until the seeds mature, then flex downward to allow the seeds to disperse; the outer bracts are always reflexed downward. Some species drop the "parachute" from the achenes; the hair-like parachutes are called pappus, and they are modified sepals. Between the pappus and the achene, there is a stalk called a beak, which elongates as the fruit matures. The beak breaks off from the achene quite easily, separating the seed from the parachute.
Taraxacum are seed dispersed ruderals that rapidly colonize disturbed soil, especially the Common dandelion which has been introduced over much of the temperate world. After flowering is finished, the dandelion flower head dries out for a day or two. The dried petals and stamens drop off, the bracts reflex , and the parachute ball opens into a full sphere. Finally, the seed-bearing parachutes expand and lift out of it. The parachute drops off the achene when it strikes an obstacle. After the seed is released, the parachutes lose their feathered structure and take on a fuzzy, cotton-like appearance, often called "dandelion snow".
PD: I CANT SEND THE IMAGE
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» Mingling with the Seed of Men....

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The Grange Biology Forum :: MIKE FARRANT :: 1st Medio :: Seed Dispersal (MFA)-
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