Sunday, June 23, 2013

Auxin: The Tipping Point. Why Plants Tip Toward the Sun

Have you ever wondered why your plants grow towards the sun?  The credit for this phenomenon is due to Auxin, a plant hormone that elongates the cells furthest from the light.  Auxin is a hormone that reacts when phototropism (Photo-Light, Tropism-movements that respond to external stimuli) occurs.  Auxin is only found on the apex of the plant, causing the top of the plant to tip towards the sun, but not the base of the stem or anywhere else; this is how you differentiate between the effects of wind and the effects of auxin; the former will knock it over throughout the stem, the latter will slightly tip it at the very top of the stem.  Auxins have many other roles in a plant's development such as healing.  Auxin regenerates vascular tissues, which carry water up from the roots to the rest of the plant and phloem which carry the nutrients down.  Auxins take effect on every plant ever to grow, no matter how little you see the results.  Auxins also induce the lateral buds to synthesize ethylene (another plant hormone which ripens the fruit).  Auxins have a part in many plant processes such as root development and flowering.  Special biosynthesized auxins are used as herbicides (Weed killers), or powders used specifically for inducing root growth.

Maybe my (Reed) freshman High school biology course was good for something after all!

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