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2. Photoprotective energy dissipation in higher plant leaves investigated by chlorophyll fluorescence decay measurements with additional radiation pulses

Creator:
Terjung, F.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
energy quenching, Pisum sativum, state 1/state 2 transition, sustained energy quenching, xanthophyll cycle, and zeaxanthin
Language:
Multiple languages
Description:
Chlorophyll (Chl) fluorescence decay measurements were performed on higher plant leaves to investigate the photoprotective mechanisms under in vivo conditions. Measurements on leaves with different amounts of zeaxanthin pointed out that zeaxanthin is necessary for most of the observed nonphotochemical energy quenching, that has to be activated by a transthylakoid ΔpH. An additional sustained energy quenching component was clearly resolved in leaves with high amounts of zeaxanthin. The changes of the Chl fluorescence decay parameters did not correlate with a photoprotective energy dissipation in the reaction centre of photosystem 2 (P680), nor with a ΔpH-mediated, zeaxanthin-independent aggregation of the antenna complexes; no indications for a state 1/state 2 transition of the main light-harvesting complex LHC2 were found.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Relationship between Rubisco activase isoform levels and photosynthetic rate in different leaf positions of rice plant

Creator:
Wang, D., Lu, Q,, Li, X. F., Jiang, Q. S., Wu, J. X., and Jiang, D. A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
ELISA, quantification, senescence, and Oryza sativa L.
Language:
Multiple languages
Description:
To investigate into the relationship between two Rubisco activase (RCA) isoforms and photosynthetic rate, a set of enzyme-linked immunosorbent assay (ELISA) were developed for accurate quantification of two RCA polypeptides based on two specific monoclonal antibodies against different RCA isoforms. The results showed that content of RCA small isoform (RCAS) was 5-fold more than that of RCA large isoform (RCAL) content in all leaves and the RCAL/RCAS ratio reached maximum in the leaf with the highest photosynthetic rate. Although the difference in two RCA polypeptides accumulation in leaves was caused by different transcript level of two isoforms, the decrease of RCAL/RCAS ratio during leaf aging was not attributed to transcriptional regulation. The leaves with higher photosynthetic capacity exhibited higher RCAL/RCAS ratio and the decrease in photosynthetic rate and Rubisco activation state highly correlated with the decline of RCAL/RCAS ratio during leaf aging. Our results suggest that there is a posttranscriptional mechanism regulating the RCAL/RCAS ratio, which may play as a regulator modulating photosynthetic capacity during leaf aging in rice plant. and D. Wang ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Salinity response pattern and isolation of catalase gene from halophyte plant Aeluropus littoralis

Creator:
Modarresi, M., Nematzadeh, G. A., and Moradian, F.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, bioinformatic analysis, catalase activity, gene isolation, 2, and 581
Language:
Multiple languages
Description:
The role of the antioxidant defense system in salt tolerance of Aeluropus littoralis has not been yet reported; therefore in the present study, the changes of catalase (CAT) activity in this halophyte plant was investigated and CAT gene was isolated. The leaves of treated and control plants were harvested at various times, starting 1 day prior to initiating treatment, then periodically at 72-h intervals for 21 days. The data collected showed that CAT activity increased significantly with time in plants treated with 200, 400, and 600 mM NaCl when compared with the control plants. Maximum enzyme activity was observed between the 6th and 12th day at all NaCl concentrations. CAT gene was isolated and cloned via pTZ57R/T cloning vector in Escherichia coli. CAT gene encoded 494 amino acids and had also high homology of 90, 87, 86, and 86% with CAT genes from Zea mays, Oryza sativa, Triticum aestivum, and Hordeum vulgare, respectively. and M. Modarresi, G. A. Nematzadeh, F. Moradian.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public