Question

When stomata open, the pH of guard cells :

• A. increases
• B. decreases
• C. remains same
• D. both a and b

Answer 1

Answer: (A)

Stomata are the pores present generally in the epidermis of leaf. A stoma contains a pore which is surrounded by two kidney shaped guard cells. During day time $C{O}_2$ is used in the photosynthesis which increase the $pH$ of guard cells. (Day) decrease in $C{O}_2=$ increase in $pH$ of guard cells. (Night) Increase in $C{O}_2$ = decrease in $pH$ of guard cells.