Abstract:
Priming is one of the seed
enhancement methods that might be resulted
in increasing seed performance (germination
and emergence) under stress conditions,
such as salinity. Salinity is a major
environmental stress which adversely
affects germination and seedling
establishment in a wide variety of crops.
The experiment was arranged as a factorial
in completely randomized design (CRD) at
Seed Research Laboratory of College of
Agriculture, University of Tehran, Iran. The
objective of this research was to evaluate
the effect of different priming methods on
seed germination of two medicinal plants
including lemon balm (Melissa officinalis
L.) and cumin (Cuminum cyminum L.)
under salinity stress. Treatments were
combinations of two levels of salinity stress
(0 and 10 dsm-1) and five levels of priming
(control = non-priming), GA3, manitol,
NaCl and distilled water) with three
replications. Seeds of lemon balm and
cumin were primed for 24 h at 25°C.
Results revealed that different growth traits
(including germination percentage,
germination rate, seedling dry weight,
plumule and radical length) significantly
(p=0.05) decreased with applying salinity.
However, priming of seeds with different
materials particularly GA3 was useful for
alleviating salt stress effects and improving
germination and seedling establishment
under salt stress. Under salinity condition,
primed seeds possessed more germination
and emergence than control. The result of
this experiment is consistent with the
hypothesis that under salinity stress, priming
can prepare a suitable metabolic reaction in
seeds and can improve seed germination
performance and seedling establishment.
