b1 controlling plant growth

plants, like animals, respond to changes in the environment- plant hormones are chemicals that control the growth of roots and shoots and the flowering and ripening of fruuits.

one group of plant hormones called auxin move through the plant in solution. they affect the plants growth by responding to gravity (geotropism) and light (phototropism) - thus being positively/negatives phototropic/geotropic.

auxin is made in the shoot tip. its distribution through the plant is determined by light and can, therfore, be unequal. this is what happens when light shines on a shoot:

• the hormones in direct…