Abstract:
The after-effects of 24 h high temperature (35 or 45 ~ treatment on the
photochemical activities and photooxidative lipid peroxidation, subsequent to their
irradiation were studied in 7-d-old etiolated rice (Oryza sativa) seedlings.
Photosystem (PS) 1 and PS 2 mediated photoreactions of thylakoids isolated from the
seedlings exposed to high temperature did not differ significantly from the thylakoids
isolated from control seedlings (25 ~ Hence, all kinds of tested thylakoids were
equally efficient in capturing and utilizing radiant energy. The high irradiance
induced loss in PS 2 activity and lipid peroxidation measured in terms of
malondialdehyde production was more rapid in thylakoids isolated from stressed
seedlings as compared to that of control seedlings. Thus the thylakoids isolated from
the stressed seedlings were more prone to photodamage than those from the control
seedlings.