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What is Transpiration (environmental)?
Grade Level:
Class 7
Space Technology, EVs, Climate Change, Biotechnology, HealthTech, Robotics, Chemistry, Physics
Definition
What is it?
Transpiration is the process where plants release water vapor into the atmosphere, mainly through tiny pores on their leaves called stomata. It's like plants sweating, helping to pull water up from the roots to the rest of the plant.
Simple Example
Quick Example
Imagine you've watered a small plant kept in a pot. After a few hours, if you tie a clear plastic bag around one of its leaves, you'll see tiny water droplets forming inside the bag. This water didn't come from the soil directly, but was released by the plant itself, showing transpiration.
Worked Example
Step-by-Step
Let's say a plant absorbs 100 ml of water from the soil in a day. Out of this, only 5 ml is used for photosynthesis and growth.
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The remaining 95 ml of water is released into the atmosphere as water vapor.
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So, the amount of water lost by transpiration is 95 ml.
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This means 95% of the absorbed water is transpired.
Answer: The plant transpires 95 ml of water, which is 95% of the absorbed water.
Why It Matters
Understanding transpiration is crucial for developing drought-resistant crops, which is vital for food security in India. It helps in climate change studies, as forests influence rainfall patterns. Environmental scientists and agricultural engineers use this knowledge to manage water resources efficiently.
Common Mistakes
MISTAKE: Thinking transpiration is the same as evaporation from soil. | CORRECTION: Transpiration is water loss *from plants*, specifically through their leaves. Evaporation is water loss from *any wet surface*, including soil, without plant involvement.
MISTAKE: Believing plants use all the water they absorb for making food. | CORRECTION: Plants use only a small fraction of absorbed water for photosynthesis. A large majority (often over 90%) is lost as water vapor through transpiration.
MISTAKE: Confusing stomata with roots. | CORRECTION: Stomata are tiny pores on leaves that release water vapor during transpiration. Roots absorb water from the soil.
Practice Questions
Try It Yourself
QUESTION: Which part of the plant primarily releases water vapor during transpiration? | ANSWER: Leaves (specifically through stomata)
QUESTION: If a plant absorbs 2 litres of water daily and uses 200 ml for its metabolic activities, how much water is lost through transpiration? | ANSWER: 1.8 litres (2000 ml - 200 ml = 1800 ml or 1.8 litres)
QUESTION: Why is transpiration important for the plant itself, even though it loses a lot of water? Name two reasons. | ANSWER: 1. It helps pull water and minerals from the roots up to the leaves (transpirational pull). 2. It helps cool the plant, just like sweating cools us down.
MCQ
Quick Quiz
Which of the following is NOT a factor affecting the rate of transpiration?
Temperature
Humidity
Light intensity
Soil pH
The Correct Answer Is:
D
Temperature, humidity, and light intensity directly affect how quickly water evaporates from leaves. Soil pH affects nutrient uptake but not the rate of water vapor release from stomata.
Real World Connection
In the Real World
Farmers in states like Punjab and Haryana use drip irrigation and choose crop varieties that are more water-efficient, partly by understanding transpiration rates. Scientists at agricultural research institutes like ICAR study how different plant species transpire to develop strategies for better water management in farming, especially during droughts.
Key Vocabulary
Key Terms
TRANSPIRATION: The process of water vapor release from plants | STOMATA: Tiny pores on plant leaves that open and close to regulate gas exchange and transpiration | HUMIDITY: The amount of water vapor in the air | TRANSPIRATIONAL PULL: The force that pulls water up from the roots to the leaves due to transpiration | XYLEM: Plant tissue that transports water and nutrients from roots to leaves
What's Next
What to Learn Next
Next, you can explore 'Photosynthesis' to understand how plants use the water they absorb to make food. You'll see how transpiration and photosynthesis are connected, helping plants survive and grow.
