3.1a Stomatal numbers

Question 1

What are stomata?

Answer 1

Pores surrounded by 2 guard cells in the aerial parts of the leaf

Question 2

What is the function of the stomata?

Answer 2

They open to allow gas exchange (carbon dioxide to diffuse in, oxygen to diffuse out) for photosynthesis.

Question 3

How should the leaf be prepared to find the the number of stomata?

Answer 3

Peel off the epidermal layer or make a replica of the leaf using PVA glue or nail polish. Observe using a microscope.

Question 4

How should the stomata distribution be estimated?

Answer 4

Count the number of stomata 3 different fields of view and take a mean.

Find the area of the field of view

Distribution= mean number of stomata in each field of view/ area of field of view

Question 5

How can the area of the field of view be calculated?

Answer 5

Calibrate the eyepiece graticule using a stage micrometer
Measure using the diameter of the field of view
Find the radius and use pi r(2) to calculate the area

Question 6

State the factors that may affect stomatal distribution

Answer 6

Habitat of plant
Growth habit of plant
Upper/lower epidermis of the leaf