Investigation of the performance of photosystem II in Melissa officinalis L. in drought stress and the effect of salicylic acid on its chlorophyll fluorescence using measuring instrument (MINI-PAM)

In order to investigate the effect of salicylic acid recovery on the activity of photosystem II and photosynthetic pigments under drought stress, in a lemon balm, a factorialexperiment was conducted in a completely randomized design with three replications. The test factors consisted of salicylic acid with three levels (0, 0.7, 1.5 mM) and drought with three levels (0, 1/3, 2/3 field capacity). For this purpose, the seeds of the lemon balm were cultured in appropriate pots after disinfection, and after growth, they were subjected to drought stress in the four-leaf stage and the salicylic acid hormone was sprayed on the leaf. Sampling was carried out in three stages (before flowering, flowering, and flowering). Under drought conditions, maximum fluorescence (Fm), fluorescence variable (Fv), maximum quantum photosystem II (Fv / Fm) efficiency and photochemical quantum efficiency increased the effectiveness of the photosystem II [Y (II)] and reduced the quantum efficiency of photosystem II [Y (NPQ)] and the non-phyto-chemical quantum efficiency of photosystem II [Y (NO)] were reduced. On the other hand, salicylic acid is used as a spray 0.7 mM resulted in an increase in Fm, Fv and Fv / Fm. At all drought levels, salicylic acid spray improved chlorophyll a and b concentrations. In total, salicylic acid spray reduced the effects of drought

کلیدواژه ها:

Melissa officinalis L. ، Salicylic acid ، Drought stress ، Maximum fluorescence ، Variable fluorescence