What is the main cause of guttation in plants?

Guttation is the process of loss of water from the surface of leaves in the form of liquid drops... Guttation occurs when root pressure is high and transpiration is low.

well first you need the sample of the temperature and gas level. i couldnt write a hypothesis unless i had some data. i think temperature changes will effect volumes of gas because gas changed into a solid or liquid at specific temperatures.