Stomata, the Plant's 'Breath' of Fresh Air

How do leaves breathe without nostrils?

Respiration! Examining Leaf Stomata Under a Microscope

Humans breathe through their nostrils, jellyfish breathe through their whole bodies, and plants rely on: stomata on leaves. Let’s take a closer look at the “lower epidermal stomata” of leaves.

Hi Mag Pro Lens

Difficulty: ★★★★★

The “stomata” on leaves are just like our nostrils. They are not cells but rather “cellular spaces” between pairs of guard cells, which facilitate passage of water vapor and gases (CO2, O2, water vapor, etc)

These stomata are controlled by “guard cells” that act as gatekeepers, regulating the opening and closing of the passage and aiding in transpiration and photosynthesis!

How to Observe

- thicker leaves are easier to sample

- the thinner the sample, the clearer and easier it is to observe

- seeing the “open stomata” on the sampled lower epidermis can be a little challenging; feel free to try a few times

Step 1: Sample the lower epidermis of the leaf

Start by facing up the backside of the leaf. Use tweezers to make a small incision along the leaf’s veins. Gently lift the cut with the tweezers to detach the lower epidermis.

Tip: The sample should be thin and translucent to ensure a clear view of the lower epidermis cells. This sampling step may require some practice.

Step 2: Place the sampled lower epidermis on a circular glass slide

Affix the sampled lower epidermis to a sampling sticker and then attach the sticker to a circular class slide.

Tip: Ensure the circular glass slide with the magnetic side is facing up, and affix the sample to the circular glass slide

Step 3: Attach the light stage to your device

Attach the glass slide to the light stage and then fix the light stage to the hi-mag pro lens for viewing

Extension Question

1. Do stomata exist on both the upper and lower surfaces of leaves?

Stomata are mostly found of the “lower epidermis” of the leaf. They are also present on the upper epidermis, but in fewer numbers, since direct sunlight usually falls on the upper surface, leading to rapid water evaporation.

2. If stomata cause water loss, why are there so many of them?
We know that plants undergo “photosynthesis” to produce glucose. The carbon dioxide needed for photosynthesis and the oxygen produced during this process requires enter and exit through stomata. Hence, stomata are crucial for plants to carry our photosynthesis.