Consequently the auxin diffuses uniformly downwards

[Yh Hoo]

Auxin as the plant hormone produced by the apical meristem in the zone of cell division of shoot and root tends to escape from the sunlight. Now if the Zone of cell division(tips) of the shoot of the plant is totally covered from sunlight supposedly the horizontal diffusion of auxin in the zone of cell division will not happen. Consequently the auxin diffuses uniformly downwards to the zone of cell elongation of the shoot. Now, will the horizontal diffusion of auxin happens in the zone of cell elongation ?? if it happens, then no use cover the tips of the shoot consisting of the zone of cell division only right ?

 

[Yh Hoo]

Hai...Hai... Anyone know ??

 

[mishrashubham]

The shoot tips have the highest concentration of phototropin, the photoreceptor proteins that actually sense the direction of light. So covering the tip would not lead to any significant bending. This means there will not be any polar distribution of auxins.