I have been taking measurements of a circuit consisting of two probes
into a closed jar which contains saline solution.  The purpose is to
compare the measurements of the circuit at different temperatures. 
When I write up the results (graphs as well), should I be mentioning
pressure in the small jar, or can it be discounted as being too small?
I need this answer fairly quickly if that's not too much to ask. 
thank you
to affect the results?

How big is the temperature difference and how well sealed are the jars?

The contribution to conductivity from pressure in your application is negligible.

hfshaw-ga

Thank you for your interest.  The temperatures vary between 10 and 50
and the seal is as complete as possible.

The contribution of pressure will indeed be negligible in your case,
but it is best scientific and engineering practice to state SP
(standard pressure -- can?t remember exact figure but basically one
atmosphere). Other term often used is ST (standard temperature, but
this kind of varies from place to place and time). Usually these two
terms are stated as STP when neither pressure or temperature is an
operator.

Best

STP is 101.3 kiloPascals.

Water is not a very compressable fluid (unlike air). Even if there was
a fair amount of pressure change on your water solution, this would
only have a very, very small affect on the water.

So unless you have the jar connected to a pump or something, I would
feel free to neglect the pressure variable.