Q.4. How do auxins promote the growth of a tendril around a support?
When the tip of the tendril touches the support, then the auxin of that side of the tip is moving away from the side of the support. As we know, auxin promotes growth. So, due to the presence of more auxin in it, the side of the tendril away from the support grows longer and faster than the support side. This type of growth, makes the tendrils bend around the support.