How do plants grow towards the sun?
Gravitropism is the term for the plant's tendancy to "know" which way is up. Phototropism is the plant's tendancy to "know" which way the source of light is... which is utilized by its photosynthetic properties.
Pretty cool mechanism of nature.
Thanks for the explanation.
Does anyone know if there are plants that do not do this? It seems to be one of the "survival of the fittest" tests. Plants that have this property have a better chance of thriving, and thus take over. But it seems like there could be sections of the world that do not have this ability, either due to their location under the sun (equatorial), or some other reason.
You are most welcome. I learned as much as you from this.
Auxin (in plants) is like a hormone but it isn't one. Perhaps a precursor. As it is explained here it acts as a growth agent much like a growth hormone in animals.
Yes the phototropic effect is an interesting phenomena. We used to demonstrate it by planting a seed that will easily germinate (bean) in a small pot, cover the pot with a large box and poke a single hole in one of the sides of the box. As the seedling emerges, it's only source of light, comes from that hole and proceeds to bend in that direction.
If you have ever passed a field of sunflowers or jerusalem artichokes at different times of the day, it is fun to notice the flowers follow the position of the sun across the sky.
I was taught "auxin" is a plant hormone. http://hcs.osu.edu/hcs300/hormone.htm [Broken]
I have noticed that the canes of my blackberries tend to grow away from the sun. They seem to prefer shade, which perhaps means an adaptation for growing in the direction toward moist soil, which would be out of the sun.
Interestingly though, in contrast, the wild blackberry brambles tend to grow toward the sun!
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