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1. Effects of Sr2+, Ca2+, and spermine on thylakoid protein and chlorophyll degradation during dark incubation of sugar beet leaf discs

Creator:
Kim, Wae Tan and Heinrich, G.
Format:
print
Type:
model:internalpart and TEXT
Subject:
Beta vulgaris L., polyamines, polyacrylamid gel electrophoresis, and cations
Language:
Multiple languages
Description:
The chlorophyll (Chl) and protein degradation during dark incubation of leaf discs was reduced by Sr2+, Ca^^, and spermine (Spm) treatments. Sr2+ inhibited most effectively the Chl degradation, which was remarkable 48 h after the treatment. The Chl degradation appeared in control discs within 24 h in the dark and Chl content decreased by about 50 % during 96 h. The proteins retained at least during 48 h of dark treatment in the presence of Sr2+, Ca2+, or Spm. The retardation effect of Sr2+, Ca2+ and Spm on the Chl loss and the disintegration of thylakoid membrane proteins may be due to a cationic protection of thylakoid membranes.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Evaluation of the specific roles of anions in electron transport and energy transfer reactions in photosynthesis

Creator:
Jajoo, A., Bharti, S., and Mohanty, P.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
bicarbonate, cations, chloride, chloroplast stsructure, oxygen evolution, photosystems 1 and 2 thylakoid, and water oxidaton
Language:
Multiple languages
Description:
Ionic environment is important in regulating photosynthetic reactions. The roles of cations, Mn2+, Mg2+, Ca2+, Na+, and K+ as cofactors in electron transport, energy transfer, phosphorylation, and carbon assimilation are better known than the roles of anions, except for chloride and bicarbonate. Only a limited information exists on the roles and effects of nitri formate, sulphate, and phosphate. In this review, we evaluate and highlight the roles of some specific anions on electron transport as well as on excitation energy transfer processes in photosynthesis. Anions exert significant effects on thyla membrane conformation and membrane fluidity, possibly by redistributing the thylakoid membrane surface charges. The anion/cation induced phase transitions in the hydrophilic domains of the thylakoid membranes are probably responsible for the various structural and co-related functional changes under stress. Anions are also important in regulation of energy distribution between the two photosystems. Anions do not only divert more energy from photosystem (PS) 2 to PS1, but can also reverse the effect of cations on energy distribution in a valence-dependent manner. Anions affect also the structure of the photosynthetic apparatus and excitation energy distribution between the two photosystems. and A. Jajoo, S. Bharti, P. Mohanty.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public