After priming, seed germination tests were carried
out. Fifty seeds each for each treatment were
placed in a plastic germination box (12 cm×18 cm)
with sand bed, and each experiment was replicated
four times. Then, seeds were incubated in a germination
chamber at 25 °C under alternating cycle of 12 h
illumination and 12 h darkness for 5 d (Zheng et al.,
2006), followed by low temperature stress at 5 °C for
3 d. After that, the seedlings were transferred to 25 °C
for recovering growth for 3 d. Seeds were considered
germinated when there was a visible coleoptile protrusion
through the sand bed. The germinated seeds
were counted daily for 11 d. Then, the germination
percentage was calculated on Day 11. The germination
index and mean germination time were calculated
as GI=Σ(Gt/Tt) and MGT=Σ(Gt×Tt)/ΣGt, respectively
(Zhang et al., 2007; Kaya et al., 2008),
where Gt is the number of germinated seeds on Day t,
Tt is time corresponding to Gt in days