The optimal time for measuring photosynthetic gas exchange using LI-COR 6400 XT is the time interval between 10-12 to midday.

Dear Tofig

That is true but during this period of time, the temperature will increase that make a difference between the first and last readings

Dear Mohammad,

if time allows you can do three repetitions.

Thank you

Dear Mohammad,

read this article, i think you can find some fomula, by that you can calculate

Article Temperature acclimation of photosynthesis: Mechanisms involv...