Question

Number of stomata is 30 and epidermal cells 120 per unit area of a leaf. The stomatal index is

• A. 0.05
• B. 0.5
• C. 0.2
• D. 0.02

Answer 1

Answer: (C)

0.2

Stomatal index is the percentage which the number of stomata forms to the total number of epidermal cells, both per unit area of concern. Stomatal index can be calculated using the equation: SI % = (S / (E+S)) * 100 where,

S = No. of stomata per unit area

E = No. of epidermal cells in the same unit area

From the question, it is given that S = 30 per unit area and E = 120 per unit area.

Therefore, SI % = (30 / (120 + 30)) * 100

SI % = (30 / 150) = 0.2 * 100 = 20, leaving the percentage, stomatal Index = 0.2

So, the correct answer is option C.