by Liliana Usvat
Blog 235-365
These trees on Slope Point, the southern tip of New Zealand, grow at an angle because they’re constantly buffeted by extreme antarctic winds.
It lies 4800 km (2982 mi) from the South Pole and 5100 km (3168 mi) from the equator, so it’s regularly exposed to unimaginable weather conditions. The air stream loops that travel over the Southern Ocean uninterrupted for 3200 km (2000 mi) make landfall at Slope Point, making for consistently extreme winds. And yet, even in this uniquely harsh environment, extraordinary beauty can be found.
When seeds germinate they are under the ground and as such are not able to detect any light source to grow towards however they are able detect the force of gravity just like humans do. No matter which way round you plant a seed the roots always grow down and the shoot grows up, the roots show positive geotropism (this means they grow in the same direction as the pull of gravity i.e. down) and the shoots show negative geotropism which is against gravity i.e. upwards. As soon as the shoot emerges above the soil it will then grow towards a source of light so that it can convert the suns energy into usable energy through photosynthesis. It is in the plants best interest to grow straight upwards so that it get as much light as it can and not be out competed by other plants.
Could a tree grow in zero-G? If so what would it look like?
Trees grow vertically because of two things: gravity and light.
Geotropism, in which microscopic particles in plant cells react to gravity, tends to make the roots grow straight down, which means that the stems grow straight up.
Phototropism tends to make plants grow vertically as well, following the direction from which light comes. Phototropism was originally called heliotropism, or bending toward the sun, until scientists found out that plants would bend toward light in general, not just sunlight.
The phenomenon was studied by Charles Darwin and his son Francis, who recognized that the bending started just below the tip. But they did not discover the mechanism that caused the bending.
Subsequent researchers found that a class of plant hormone called auxins can regulate the growth of plant cells, interacting with other plant substances to direct and control the plant’s final shape, both above and below the ground.
In a growing tree, auxins, produced at the growth tip, promote the elongation of plant cells. Auxins are present in greater concentrations on the darker side of the plant shaft, so those cells grow longer than the cells exposed to light.
Thus, the tree bends toward the light. inner needles senesce, or grow old, turning yellow or brown, and drop from the tree after one to several years, depending on the species. By November of most years, for example, white pines may have only a year’s worth of needles attached to the tree.
Blog 235-365
These trees on Slope Point, the southern tip of New Zealand, grow at an angle because they’re constantly buffeted by extreme antarctic winds.
It lies 4800 km (2982 mi) from the South Pole and 5100 km (3168 mi) from the equator, so it’s regularly exposed to unimaginable weather conditions. The air stream loops that travel over the Southern Ocean uninterrupted for 3200 km (2000 mi) make landfall at Slope Point, making for consistently extreme winds. And yet, even in this uniquely harsh environment, extraordinary beauty can be found.
Why do trees grow vertically instead of horizontally?
When seeds germinate they are under the ground and as such are not able to detect any light source to grow towards however they are able detect the force of gravity just like humans do. No matter which way round you plant a seed the roots always grow down and the shoot grows up, the roots show positive geotropism (this means they grow in the same direction as the pull of gravity i.e. down) and the shoots show negative geotropism which is against gravity i.e. upwards. As soon as the shoot emerges above the soil it will then grow towards a source of light so that it can convert the suns energy into usable energy through photosynthesis. It is in the plants best interest to grow straight upwards so that it get as much light as it can and not be out competed by other plants.
Could a tree grow in zero-G? If so what would it look like?
The
complication that needs to be overcome is that plants make use of
gravity when planted to orient themselves (as they can't rely on being
planted the right way up), so that their roots go down and their sprouts
go up. Without gravity, they will tend to just stay at around the same
depth and not sprout.
One astronaut reported that this was simple enough to fix, however, just by plucking the ends out of the soil, pulling them to the surface, when they first sprout. From this point, the plant can orient itself using light and will continue to grow. Roots don't suffer as much, as they just grow away from the seed and avoid light (the surface), so develop relatively normally.
After this, growth is mostly normal The resulting plants can look a little unusual because they don't have the usual drooping from gravity, so will tend to be more upright.
One astronaut reported that this was simple enough to fix, however, just by plucking the ends out of the soil, pulling them to the surface, when they first sprout. From this point, the plant can orient itself using light and will continue to grow. Roots don't suffer as much, as they just grow away from the seed and avoid light (the surface), so develop relatively normally.
After this, growth is mostly normal The resulting plants can look a little unusual because they don't have the usual drooping from gravity, so will tend to be more upright.
How Do Trees On a Hillside or Slope Grow Straight Up?
Trees grow vertically because of two things: gravity and light.
Geotropism, in which microscopic particles in plant cells react to gravity, tends to make the roots grow straight down, which means that the stems grow straight up.
Phototropism tends to make plants grow vertically as well, following the direction from which light comes. Phototropism was originally called heliotropism, or bending toward the sun, until scientists found out that plants would bend toward light in general, not just sunlight.
The phenomenon was studied by Charles Darwin and his son Francis, who recognized that the bending started just below the tip. But they did not discover the mechanism that caused the bending.
Subsequent researchers found that a class of plant hormone called auxins can regulate the growth of plant cells, interacting with other plant substances to direct and control the plant’s final shape, both above and below the ground.
In a growing tree, auxins, produced at the growth tip, promote the elongation of plant cells. Auxins are present in greater concentrations on the darker side of the plant shaft, so those cells grow longer than the cells exposed to light.
Thus, the tree bends toward the light. inner needles senesce, or grow old, turning yellow or brown, and drop from the tree after one to several years, depending on the species. By November of most years, for example, white pines may have only a year’s worth of needles attached to the tree.
