Transpiration

noun (uncountable)

/ˌtrænspaɪˈreɪʃən/

Transpiration is the process by which water absorbed by plant roots moves upward through the xylem and is released as water vapour through tiny pores called stomata on leaf surfaces, driven by the vapour pressure gradient between the leaf interior and the atmosphere. It constitutes up to 10% of the moisture in the atmosphere and plays a major role in the local water cycle, influencing rainfall patterns. In India, transpiration from forests — particularly the Western Ghats — contributes significantly to the south-west monsoon's inland moisture flux, making deforestation a hydro-climatic concern addressed under the National Forest Policy.

✍️ Usage in a UPSC answer

Satellite-derived estimates of evapotranspiration from India's Gangetic agro-ecosystems reveal that transpiration accounts for nearly 60% of total water flux, a figure critical for calibrating the Jal Shakti Abhiyan's basin-level water budgets.

Synonyms

evapotranspirationstomatal water lossfoliar evaporationperspiration (botanical analogue)

Antonyms

water absorptionguttation (water exuded as liquid)condensation

🌱 Word Family

transpire (verb), transpirational (adjective), transpirate (verb, rare), evapotranspiration (noun)

🔡 Root

Latin trans- = across, through + spirare = to breathe

📜 Etymology

Formed from Latin trans- (across) and spirare (to breathe or exhale), the word literally means 'breathing across'. It entered English in the 15th century in a general physiological sense (exhalation of vapour through the skin), and was narrowed to its specific botanical meaning by the 18th century as plant anatomy developed. The Latin root spirare also gives 'respiration', 'inspire', and 'perspiration', all sharing the sense of air movement.

🧠 Memory Hook

Transpiration is plants 'breathing across' (trans + spirare) their leaves — imagine a plant exhaling water vapour through thousands of tiny mouths (stomata) on each leaf, releasing moisture into the air just as we exhale humid breath.

⚗️ General Science 📖 Seen in: Human Body Systems — Organ Systems, Ph...

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