Q. Stoma opens, when
A) Guard cells swell due to an increase in their water potential
B) Guard cells swell by endosmosis due to influx of hydrogen ions (protons)
C) Guard cells swell by endosmosis due to efflux of potassium ions
D) Guard cells swell due to a decrease in their water potential
Explanation
During day time, photosynthesis occurs in guard cells because they contain chloroplast. The soluble sugar formed by this process decreases the water potential of guard cells and hence, resulting in stomatal opening.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.