External Factors

External Factors:

These comprise conditions of the environment that affect the rate of transpiration. The external factors are wind, humidity, atmospheric pressure, temperature, light and water.


Humidity refers to the quantity of water vapor existed in the atmosphere. When humidity is high, rate of evaporation is low and therefore the rate of transpiration is slow.


Wind is air in motion that improves the rate of evaporation. Wind raises the rate of transpiration. However winds at high velocity bring around closure of stomata and therefore decrease the transpiration rate.

Atmospheric Pressure:

Low atmospheric pressure raises the rate of transpiration. Water vapor from transpiring surfaces quickly moves into the atmosphere that is at low pressure.


Rise in temperature raises the rate of transpiration as high temperature causes the water in intercellular spaces to vaporize at a faster rate.


Light influences opening of stomata and therefore rate of transpiration is high in light and low in darkness.


Less amount of soil water reduces the rate of transpiration. When the rate of transpiration exceeds the rate of absorption, the stomata get closed the cells lose their turgidity and the plant wilts. When the plant recovers the turgidity, it will recover its original position and this is termed as incipient wilting. When the wilting is irreversible it is termed as permanent wilting.

Latest technology based Biology Online Tutoring Assistance

Tutors, at the www.tutorsglobe.com, take pledge to provide full satisfaction and assurance in Water transport homework help via online tutoring. Students are getting 100% satisfaction by online tutors across the globe. Here you can get homework help for Water transport, project ideas and tutorials. We provide email based Water transport homework help. You can join us to ask queries 24x7 with live, experienced and qualified online tutors specialized in Water transport. Through Online Tutoring, you would be able to complete your homework or assignments at your home. Tutors at the TutorsGlobe are committed to provide the best quality online tutoring assistance for Biology homework help and assignment help services. They use their experience, as they have solved thousands of the Biology assignments, which may help you to solve your complex issues of Water transport. TutorsGlobe assure for the best quality compliance to your homework. Compromise with quality is not in our dictionary. If we feel that we are not able to provide the homework help as per the deadline or given instruction by the student, we refund the money of the student without any delay.

2015 ┬ęTutorsGlobe All rights reserved. TutorsGlobe Rated 4.8/5 based on 34139 reviews.