Inhibition of photosystems I and II activities in salt stress-exposed Fenugreek (Trigonella foenum graecum).
J Photochem Photobiol B
; 105(1): 14-20, 2011 Oct 05.
Article
em En
| MEDLINE
| ID: mdl-21764595
ABSTRACT
Fenugreek (Trigonella foenum graecum) seedlings were exposed to increasing NaCl concentrations in the growth medium to examine the effect of salt stress on the electron transport reactions of photosynthesis. Activities of both photosystem II (PSII), measured by chlorophyll fluorescence, and photosystem I (PSI), measured by P700 photooxidation, were decreased by salt stress. The inhibition proceeded in a two step manner. At the lower salt concentrations used and shorter exposition periods, electron transfer between the quinone acceptors of PSII, Q(A) and Q(B), was strongly retarded as shown by an increased amplitude of the OJ phase of the OJIP chlorophyll fluorescence induction traces and slowed chlorophyll fluorescence relaxation kinetics following a single turn-over flash. The above indicated a disturbance of the Q(B) binding site likely associated with the first step of photoinhibition. In the second step, strong photoinhibition was observed as manifested by increased F(0) values, declined F(v)/F(0) and loss of photoactive P700.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cloreto de Sódio
/
Trigonella
/
Complexo de Proteína do Fotossistema I
/
Complexo de Proteína do Fotossistema II
Idioma:
En
Revista:
J Photochem Photobiol B
Assunto da revista:
BIOLOGIA
Ano de publicação:
2011
Tipo de documento:
Article