9700 · 14.2
Homeostasis in plants — FAQ
Frequently asked questions for 9700 Homeostasis in plants. Direct answers first, then deeper explanation — then practise with marking.
What is plant homeostasis and why is it important in A Level Biology 9700?
Plant homeostasis is the process by which plants maintain stable internal conditions, such as water potential, temperature, and carbon dioxide levels, despite changes in their external environment. It's crucial for their survival, growth, and efficient metabolic functions like photosynthesis. For A Level Biology 9700, understanding this topic is vital for Paper 4 as it explains how plants adapt to different environments. You can explore this further with our free revision lessons and past papers.
How do plants regulate their water potential?
Plants primarily regulate water potential through controlling stomatal opening and closing, influenced by light, internal CO2, and the hormone abscisic acid (ABA). They also employ various structural adaptations like thick cuticles, sunken stomata, and hairs to reduce water loss (transpiration). Efficient root uptake mechanisms also contribute to maintaining water potential. Our free biology course covers these mechanisms in detail.
What role does abscisic acid (ABA) play in plant homeostasis?
Abscisic acid (ABA) is a crucial plant hormone that acts as a 'stress signal' in response to water deficit. When a plant experiences water stress, ABA is produced in the roots and transported to the leaves, triggering the guard cells to become flaccid and close the stomata. This action significantly reduces water loss through transpiration, thus playing a vital role in conserving water and maintaining the plant's water potential.