Which one of the following is involved in the closing of stomata?
Correct answer: C. Abscisic acid
- A. Gibberellins
- B. Ethane
- C. Abscisic acid
- D. Cytokinine
Explanation
Answer is "Abscisis acid"Explanation: Hormones are involved in stomatal movement in plants. At high temperature when leaf cells start wilting a hormone is released by mesophyll cells. This hormone is called abscisic acid. This hormone stops the active transport of K+into guard cells, overriding the effect of light and CO2 concentration. So K+ pumping stops. Stomata close.
Last updated
About Circulation
The circulatory system covers the chambers, valves and conducting pathway of the human heart, along with the cardiac cycle and control of heartbeat. It compares arteries, veins and capillaries by structure and function, and explains how the lymphatic system returns tissue fluid, transports absorbed fats and supports immunity.
Practise Circulation
695 free Circulation MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Biology questions like this
Biology is on 6 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
1% of the absorbed water is used by plants in its activities during:
75% osmotic pressure of blood is maintained by:
A bottle filled with previously moistened mustard seeds and water was screw-capped tightly and kept in a corner. It blew up suddenly after about half an hour. The phenomenon involved is
A column of water within xylem vessels of tall trees does not break under its weight because of:
A destarched leaf on a potted plant was covered with Black (A) Transparent (B) strips of paper as shown in figure. After 6 hours of exposure to sunlight the leaf was removed from the plant and tested for starch. Which are the following will be the correct observation?