Characterizing photoinhibition and photosynthesis in juvenile-red versus mature-green leaves of Jatropha curcas L

• Published in: Plant physiology and biochemistry 2014-06, Vol.79, p.48-59
• Main Authors: Ranjan, Sanjay, Singh, Ruchi, Singh, Munna, Pathre, Uday V., Shirke, Pramod A.
• Format: Article
• Language: English
• Subjects: Anthocyanin reflectance index; Biological and medical sciences; Chlorophyll - metabolism; Chlorophyll a fluorescence; Fundamental and applied biological sciences. Psychology; Jatropha - metabolism; JIP test; P700 redox state; Photoprotection; Photosynthesis - physiology; Plant Leaves - metabolism; Plant physiology and development
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2014.03.007

The new leaves of Jatropha curcas (L.) appear dark red in colour due to the presence of anthocyanin pigments, these leaves subsequently turn green on maturity. The aim of the study was to characterize the photosynthetic efficiency of the juvenile red and mature green leaves and to understand the possible role of anthocyanin pigment in the juvenile leaves of J. curcas. We studied the localization of anthocyanin pigment, reflectance properties, diurnal gas-exchange performance, carboxylation efficiency and photosynthetic efficiency under different light intensities by investigation of the photochemical and non-photochemical energy dissipation processes related to Photosystem II (PSII) and Photosystem I (PSI), of the juvenile and the mature leaves of J. curcas. The JIP test analysis of chlorophyll a fluorescence transients and the gas-exchange studies revels the low photosynthetic efficiency of red leaves is due to the immaturity of the leaf. The low value of quantum yield of non-photochemical energy dissipation due to acceptor side limitation, Y (NA) under high light in the red leaf, suggests that over-reduction of PSI acceptor side was prevented and it results in the accumulation of oxidized P700, which dissipates excess light energy harmlessly as heat and thereby alleviate photoinhibition of PSI in case of the juvenile red leaves. Further our results of photoinhibition and relaxation on exposure of red and green leaves to monochromatic blue light showed that effective quantum yield of PSII recovers faster and completely under darkness in juvenile red leaves as compared to mature green leaves, supporting the role of anthocyanin pigments in protecting both PSII and PSI in the red leaves. [Display omitted] •Red leaves are photosynthetically less efficient by 25% than mature green leaves.•Dark respiration was two times higher in red than the green leaves.•Anthocyanin Reflectance Index was 9 times higher in red leaves than the green leaf.•PSII quantum yield relaxed faster in red leaves on photoinhibition with blue light.•Anthocyanin pigments protect PSII and PSI in juvenile red leaves of Jatropha curcas.