While hiking after school one day, you came across several plants that you weren’t familiar with. You took a leaf sample from each, and went back to the lab and did a stomata density count. Using a 40x objective with a field diameter of 0.5 mm, you got the following counts: Sample 1: you counted 8 stomata Sample 2: you counted 42 stomata Calculate the stomata density for each of your samples

Sample 1: 41 stomata per mm^2

Sample 2: 214 stomata per mm^2

Explanation:

The density of the stomata on a leaf is the number of stomata on a leaf per leaf area. It is measured per unit area i.e. per square mm (mm^2).

The unknown leaf was taken to the laboratory and a microscope with a field diameter of 0.5mm was used. Since the density is measured per unit area, we need to find the area of the field of view.

To find the area, we use πr^2, which π= 3.142 and r= radius (diameter/2 i.e. 0.5/2 = 0.25mm)

Hence, using Area = πr^2

= 3.142 × 0.25 × 0.25

= 0.196

Therefore, the area of the field of view is 0.196mm^2

The stomata count for the samples are:

Sample 1: 8 counts

Sample 2: 42 counts

Area of field of view on microscope= 0.196mm^2

Therefore, the stomatal density of each sample of leaf in a single count is calculated by saying;

Number of stomata × 1/area

Sample 1= 8 × 1/0.196

= 8 ÷ 0.196

= 40.82

Approximately, we have 41 stomata per square mm as the density for sample 1

For sample 2: 42 × 1/0.196

= 42 ÷ 0.196

= 214. 2857

Approximately, we have 214 stomata per square mm as the density for sample 2.