Seeds of spinach (
Spinacia oleracea
L. cv.
Ace
) were
purchased from Syngenta Seed Company, Korea. Plants
were grown in the experimental
fi
eld of Chonbuk National
University, Chonju Korea. Two-month-old spinach plants,
which were grown in pots, were then transferred to the
laboratory. After 1 week of acclimation at normal light
(15
m
mol m
2
s
1
), they were illuminated for 24 h with
excessive photons (HI, 1300
m
mol m
2
s
1
) using a 150 W
HQI lamp.