Showing posts with label Seeds. Show all posts
Showing posts with label Seeds. Show all posts
2.13.2012
2.03.2012
Another view on the Seed Dispersal
Biotic Seed Dispersal
http://database.portal.modwest.com/start.php
The dispersal of seeds can be split up into two major classes: biotic or abiotic dispersal. Abiotic dispersal methods use wind, water, or other abiotic forces to distribute seeds, while biotic dispersal relies on the movements of animals or other organisms for dispersal.
The advantages of biotic dispersal are several. Animal movements are predictable and correlated with environmental cues, allowing plants to time seed production to correspond with these movements and environmental changes. Animals can also carry large, heavy seeds with more food for seedling growth thus enhancing the chances for reproductive success of the parent species. Then too, animals have food preferences that impose a sort of consistency on their movements and feeding locations. The presumption here is that if an animal shows a preference for a food type, and the source plant for that food has a selective preference for certain niches, as the animal moves from one location or niche to another in search of that food these locations will be relatively well suited to colonization by the seeds from the plant. And finally, animals can recognize color and odor cues. Mechanisms of animal transport include several different passive methods. In some instances, transport relies on some sort of adhesive (burrs, glues, etc.) to attach seeds to the animal. In other instances, ingestion[섭취] and subsequent off-site defecation[배변] of seeds is the method of dispersal. And finally, fruit hoarding[비축하기], or excess food production satiates[실컷 만족시키다] seed predators. Biotic seed dispersal may inspire a biomimetic systems for the distribution of materials in industrial cycles |
2.01.2012
Biotic Seed Dispersal
http://database.portal.modwest.com/start.php
The dispersal of seeds can be split up into two major classes: biotic or abiotic dispersal. Abiotic dispersal methods use wind, water, or other abiotic forces to distribute seeds, while biotic dispersal relies on the movements of animals or other organisms for dispersal.
The advantages of biotic dispersal are several. Animal movements are predictable and correlated with environmental cues, allowing plants to time seed production to correspond with these movements and environmental changes. Animals can also carry large, heavy seeds with more food for seedling growth thus enhancing the chances for reproductive success of the parent species. Then too, animals have food preferences that impose a sort of consistency on their movements and feeding locations. The presumption here is that if an animal shows a preference for a food type, and the source plant for that food has a selective preference for certain niches, as the animal moves from one location or niche to another in search of that food these locations will be relatively well suited to colonization by the seeds from the plant. And finally, animals can recognize color and odor cues. Mechanisms of animal transport include several different passive methods. In some instances, transport relies on some sort of adhesive (burrs, glues, etc.) to attach seeds to the animal. In other instances, ingestion[섭취] and subsequent off-site defecation[배변] of seeds is the method of dispersal. And finally, fruit hoarding[비축하기], or excess food production satiates[실컷 만족시키다] seed predators. Biotic seed dispersal may inspire a biomimetic systems for the distribution of materials in industrial cycles |
12.02.2011
Friday Fabulous Flower – At the Stage of Seed Dispersal
http://phytophactor.fieldofscience.com/2011/01/friday-fabulous-flower-at-stage-of-seed.html
This isn’t precisely a flower, but then again it is a flower at the stage of seed dispersal, but a very pretty and unusual image the result of having gelatinous seed coats. This also isn’t exactly a common plant especially when viewed this way. So who recognizes this very nifty image?
This isn’t precisely a flower, but then again it is a flower at the stage of seed dispersal, but a very pretty and unusual image the result of having gelatinous seed coats. This also isn’t exactly a common plant especially when viewed this way. So who recognizes this very nifty image?
Closing the seed dispersal loop_Benjamin C.Wang and Thomas B. Smith
Box 1. The seed dispersal cycle
It is important to distinguish between the process of seed dispersal, whereby seeds are moved from parent plants, and the seed dispersal cycle, which is a succession of processes (including the process of seed dispersal) whereby seeds produced by an adult plant are moved from the parent plant, germinate to seedlings, and recruit to adult plants,
influencing the fruit and seed availability of the next generation (Fig. I). Although seed dispersal is only one of the many processes in this cycle, we have chosen to call it the seed dispersal cycle to emphasize its role as a ‘demographic bridge’ linking the end of the reproductive cycle of adult plants with the establishment of their offspring [a]. Not all seeds are dispersed, and most dispersed seeds do not complete the seed dispersal cycle. However, the parents that produce seeds that successfully complete the cycle pass a disproportionate amount of their genes to the next generation and thus have a disproportionate influence on the vegetation composition of the succeeding generations.
Reference a Herrera, C.M. et al. (1994) Recruitment of a mast-fruiting, bird-dispersed
tree: bridging frugivore activity and seedling establishment. Ecol. Monogr. 64, 315–344
Fig. I. The two main approaches used to investigate animal-mediated seed dispersal
and its consequences: (1) Working forwards entails trying to follow the seed dispersal
process in the direction that it happens in nature (in the direction of the arrows). These
studies tend to focus on patterns and processes on the right side of Fig. I (given in red),
and many of them are classified as ‘seed dispersal studies’. A major hurdle has been
the difficulty of following the dispersers from parent plants to where they deposit
seeds to track the fates of those seeds. (2)Working backwards examines the
consequences of the seed dispersal process – seed, seedling, sapling, and adult plant
distribution – and tries to deduce the influence of seed dispersal in determining those
patterns. These studies focus on patterns and processes on the left side of Fig. I (given
in green), and many of them are studies of plant demography. Processes (given in
bold) generate the patterns (given in boxes) that can be measured.
http://www.rhizomia.net
11.25.2011
BBC_Earth News_Vine seeds become 'giant gliders'
http://news.bbc.co.uk/earth/hi/earth_news/newsid_8391000/8391345.stm
Remarkable footage has been captured of falling Alsomitra vine seeds, which use paper-thin wings to disperse like giant gliders.
The seeds, which are produced by a football-sized pod, can glide hundreds of metres across the forest.
That ensures that the seeds fall far from their parent, giving the next generation of vines a head start.
A BBC team captured the film of the gliding seeds for the natural history series Life.
The Alsomitra (Alsomitra macrocarpa) vine is a type of climbing gourd, and is also known as the Javan cucumber.
It grows in the forests of Java, Indonesia.
Each pod contains up to 400 individual seeds, each of which peels away from the parent tree in the wind.
Dispersing its seeds in this way is vital to the vine, which must avoid producing new plants that land close, competing for sunlight and soil nutrients.
The wings decay upon landing
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The aerodynamics of the giant Alsomitra seeds were studied by two Japanese engineers, Akira Azuma and Yoshinori Okuno more than 20 years ago.
They found that design of the seed is so good that it achieves a descent angle of just 12 degrees, a property that has led to the seed's shape inspiring the design of aircraft.
That means it falls just 0.4m each second, compared to 1m per second for many winged seeds that rotate as they fall.
Once the seed has fallen to the ground, the wings decay, rotting away to leave the germinating seed.
A new vine then grows skyward toward the canopy and sunlight.
At up to 15cm across, and weighing around 300mg, they are among the largest winged seeds produced by any plant. Yet the seed's wings are less than 10 micrometres thick.
Generally, the seeds fall to the ground in broad circles up to 6m across.
However, compared to many other plant seeds, those of the Alsomitra vine can glide in a relatively straight line with a following wind, helping them fall further away from the parent plant.
"Gliding seeds" is broadcast within the Plants episode of the BBC series Life at 2100GMT on BBC One on Monday 7 December.
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