TROPICAL GRASSLANDS, cilt.43, ss.171-177, 2009 (SCI-Expanded)
Seeds of alfalfa (Medicago sativa) and white
clover (Trifolium repens) were primed in 3
priming solutions [2% NaCl, 2% KNO3 and 300
g/L polyethylene glycol (PEG)] for 2 days at
20°C and their subsequent germination compared
with that of untreated seed. Four replications
of 50 seeds for germination and 25 seeds for
emergence were arranged in a 2-factor factorial
completely randomised design. All priming treatments
significantly (P<0.05) advanced germination
rate and percentage of white clover at 15°C,
but produced minimal or negative effects on
alfalfa. Priming with PEG significantly (P<0.05)
reduced time to 50% of final germination percentage
(G50 = 4.2 days) of white clover in comparison
with control seeds (G50 = 6.5 days). The
results indicated that priming seeds in KNO3 for
2 days at 20°C could improve germination rate
and germination percentage of white clover at
15oC. Possible reasons for the differing responses
in the two species are discussed.