Auxin and Gravitropism

[MowgliR]

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In Cliff's, they mention that Auxin does respond to gravity(pg 176 under Auxin), but then they say that they dont (pg 177 after gravitropism).

Are they saying gravity doesnt affect the distribution of hormones?

Can someone clear this up?

 

[herkulease]

what they are saying Auxins influences the plants response to gravity. It however is not influenced by gravity.

 

[dental13]

There are two types of growth that Auxins involve in. First one is phototropism; when the light strikes one side, the auxin supply on that side is reduced, therefore creating asymmetrical growth.

For Geotropism (negative one and positive one)
For the (-) Geotropism, the plant grows upward, away from the gravity. The gravity causes auxins to concentrate more on lower part compare to upper part. This cause cells on lower part to elongate faster than cells on the upper side, causing the plant to grow vertically.

For (+) Geotropism
This is gravity affecting root cells. The auxin concentration is same as (-) Geotropism, but root cells that have high concentration of auxins are inhibited from growing. Therefore, the cells on the upper side grow, causing the root to turn downwards.

The auxin affects differently, it depends where they are located, if they are located in vascular part, it will lead to - geotropism (causing shoots to grow upward). If they are located in root cell it will lead to + geotropism (causing shoots to grow downward).

Please correct me if I am wrong 🙂🙂🙂

 

[RCT PC CRN]

There are two types of growth that Auxins involve in. First one is phototropism; when the light strikes one side, the auxin supply on that side is reduced, therefore creating asymmetrical growth.

For Geotropism (negative one and positive one)
For the (-) Geotropism, the plant grows upward, away from the gravity. The gravity causes auxins to concentrate more on lower part compare to upper part. This cause cells on lower part to elongate faster than cells on the upper side, causing the plant to grow vertically.

For (+) Geotropism
This is gravity affecting root cells. The auxin concentration is same as (-) Geotropism, but root cells that have high concentration of auxins are inhibited from growing. Therefore, the cells on the upper side grow, causing the root to turn downwards.

The auxin affects differently, it depends where they are located, if they are located in vascular part, it will lead to - geotropism (causing shoots to grow upward). If they are located in root cell it will lead to + geotropism (causing shoots to grow downward).

Please correct me if I am wrong 🙂🙂🙂

👍 Perfect

Auxins is weird growth substance in plants in terms that they have different effect at different location. dental13 explained is very well. Also the growth and other physiology is a gross effect of substances (i.e. Auxins + Gibberellins + ..etc). I think lot of physiology in plants is not well understood and may be the current area of research. But one thing Auxins does behave differently in Shoot and Root system why does it that why..I don't know !!!