Did you know? Just like we release water vapour through our mouths as we breathe, so do plants through their stomata - tiny, pore-like structures on the surfaces of leaves. Plants use their roots to absorb water and nutrients from the soil, drawing it upwards into their stems and leaves. Some of this water is then returned to the atmosphere by the process known as transpiration.

 Why do plants need to transpire?

The loss of water (or transpiration) plays a vital role in maintaining healthy plant growth, water balance, and overall longevity. More specifically, plants transpire for 3 main reasons:

1. Nutrient uptake – the rate of transpiration actually determines your edibles’ yield. Turgor pressure keeps the plant cells full and turgid, owing to the transpiration stream of water from roots to shoots. In agriculture, transpiration is essential in producing healthy crops.
2. Cooling – to manage heat and drought stress, transpiration rates are crucial as this process brings down the temperature of leaves, the largest plant organ. However, losing too much water can leave plants dehydrated.
3. Photosynthesis – water flow efficiency is intricately connected with photosynthesis through the stomata. A lot of the water absorbed from the soil is used for photosynthesis, cell expansion, and growth. A single tree reaching 20 meters high can take up between 10 litres to 200 litres a day!

Clearly, transpiration is a big deal. Get the kids involved and let’s bring this invisible miracle to light.

Experiment time

You will need

• A ziplock bag
• String
• A leafy branch of a tree

Try this: Compare transpiration rates and see how the environment affects plants by conducting separate experiments on both sunny and cloudy days.

Step 1: Find a plant in the garden with a nice leafy branch where your bag will fit over.

Step 2: Cover the section of the branch with the ziplock bag and then seal it tightly with some string around the stem.