Did the relative humidity inside the pollination bag decrease linearly or show cyclic change? Were the bags subjected to changes in temperature due for instance to solar radiation?

Dear Harry, if I have well understood: you put a bag around a plant then you seal the bag. This way the water content inside the bag was fixed in the moment of the sealing. Then you leave the bag exposed to the solar radiation. In such a way the solar radiation increases the temperature of the gas inside the bag (part of the gas is water vapor). Since I think you refer to Relative humidity which is described approx by RH=e/es (e= actual vapor pressure and es = saturation vapor pressure) when the temperature inside the bag increases then "es" stays nearly constant (or it changes much less then "e") and "e" increases too, so the ratio changes.

Therefore, you should expect a RH higher during the night than during the sunny hours in a cyclic change.

Hello Gentleman, thank you both very much for your help. To answer your questions Shinsaku above the humidity decreased linearly and the bags were placed in the sun so yes solar radiation affected the temperature. Also having since done the test I have read some research undertaken by Aberystwyth University in the late 80s which confirmed your thoughts Denis as they also sealed each bag with a fixed water content. I think that if I run the trial longer (overnight) I am likely to have a wider set of results which reflects the goal of the experiment. Thank you for your help, I really appreciate it!