Final answer:
Plants respond to changes in light direction through phototropism, coordinated by the hormone auxin, which promotes growth towards light. Other plant hormones like gibberellins, cytokinins, abscisic acid, and ethylene also regulate various growth responses to environmental stimuli.
Step-by-step explanation:
How Plant Hormones Coordinate Responses to Environmental Changes
Plants respond to environmental stimuli such as changes in light direction through complex systems involving hormones. While animals can relocate to adapt to their surroundings, plants rely on chemical signals to respond to stimuli like light, gravity, and touch. For example, in response to light direction, plants exhibit phototropism, a phenomenon where growth is directed either towards or away from light.
The process of phototropism is regulated by plant hormones such as auxins. These hormones are synthesized in plant cells and can act where they are produced or be transported to other parts of the plant. Auxins are specifically involved in directional growth toward light by accumulating on the darker side of the plant, causing the cells there to elongate more than those on the lighter side, hence bending the plant towards the light.
This growth response is part of the wider system of photomorphogenesis, which is how plants use light to influence their growth and development. Other hormones like gibberellins, cytokinins, abscisic acid, and ethylene also play roles in various plant responses such as stem elongation, seed germination, and fruit ripening.