I conducted field experiments in which plants were not dark adapted. I have used qp, NPQt, PHiNO and photo protection in my report, but the formula which i know for qP is as follows;
q P = (FM’ –Fo) (FM’-f’)
I believe that this formula is for dark adapted. what formula should i use. lastly i need formulas for Photo protection. Please assist.
The qL parameter was introduced by lab in 2004 in
Kramer et al (2004) Photosynthesis Research 79: 209–218, 2004
New fluorescence parameters for the determination of QA redox state and excitation energy fluxes
See EQ. 25:
qL = ((1/Fs) - (1/Fm'))/((1/Fo') - (1/Fm'))
The older parameter, qP, is easier to calculate:
qP = (Fm'-Fs)/(Fm'-Fo')
But, the qL parameter is preferred over qP because it is based on a more appropriate model for the antenna complexes, as described in the text.
Both qL and qP do not need dark adapted values. However the traditional NPQ does and that is why we introduced some new parameters in 2017.
The NPQ(t) and related parameters use the F0' as the reference rather than Fm. This lets you make these measurements much faster, because you do not have to completely dark adapt. The approach and formulas are described in the paper
Tietz et a., Plant Cell and Environment, 40,1243–1255.
Let me know if you cannot get access to this journal.
There are also some older threads related to this topic:
Thanks for the formula and guidance on qL and qP. Thanks once again for link of your journal (Tietz et a.,) you gave me, however am failing to access it. Please help me.