NaCl stress aggravates photoinhibition of photosystem II and photosystem I in Capsicum annuum leaves under high irradiance stress
NaCl胁迫加重强光胁迫下超大甜椒叶片的光系统II和光系统I的光抑制

Aims Our aim was to study effects of salt stress and high irradiance on photoinhibition of photosystem II (PSII) and I (PSI) in leaves of sweet pepper (Capsicum annuum). Methods We used the chlorophyll a fluorescence technique and the JIP-test to study the responses of sweet pepper leaves to salt stress with different NaCl concentrations and under high irradiance (1 000 μmol·m–2·s–1). Important findings The chlorophyll a fluorescence induction curves changed greatly as induced by NaCl stress under high irradiance, and photoinhibition of PSII was aggravated with apparent effects on PSII reaction centers and the acceptor side. Also, the donor side of PSII was damaged by high NaCl concentration under high irradiance. Additionally, the activity of PSI reaction centers (P700+) was inhibited by NaCl stress under high irradiance. Therefore, NaCl stress could aggravate photoinhibition of sweet pepper photosystem under high irradiance, and photoinhibition was greater with higher NaCl concentration. However, PSI photoinhibition was less than PSII photoinhibition. Additionally, high NaCl concentration could induce both damage to PSII donor sides and PSI.