Question

The number of stomata and epidermal cells in 1${mm}^2$ area of abaxial surface of the leaves of A, B, C and D plants are given below. Identify the plant having the least stomatal index.

Plant	Number of stomata	Number of epidermal cells
A B C D	20 40 50 70	100 160 300 560

• A. B
• B. C
• C. D
• D. A

Answer 1

Answer: (C)

D

Stomatal index (SI)$=\frac{S}{S+E}\times 100$

Here, S= no. of stomata per unit area and E= no. of epidermal cells in the same unit area.

Therfore, the stomatal index of the plant are as follows:

A= (20/ 120) X 100= 16.6

B= (40/ 200) X 100= 20

C= (50/ 350) X 100= 14.2

D= (70/ 630) X 100= 11.1

Thus, the correct answer is option C.