Journal of Stress Physiology & Biochemistry, Vol. 6 No. 4
2010, pp. 66-80 ISSN 1997-0838
Original Text Copyright (cc) 2010 by Wadhwa, Kumari and Sharma
ORIGINAL
ARTICLE
Data source : Google Scholar
QueryDate : 2016-12-24
Cites : 2
Varying light regimes in naturally growing Jatropha curcus: pigment, proline
and photosynthetic performance
Wadhwa R., N. Kumari* and V. Sharma
Department of Bioscience and
Biotechnology, Banasthali University, Rajasthan-304022, India *E-mail: nilima_km@yahoo.com
Fax: 91-1438-228365
Received October 29, 2010
Light stress is a major abiotic stress which adversely
affects productivity of the plants. Tolerance to abiotic stresses is
very complex, due to the intricate of interactions between stress
factors and various molecular, biochemical and physiological phenomena
affecting plant growth and development. In many cases, high yield
potential can contribute to yield in moderate stress environment. We
studied chlorophyll (Chl) a fluorescence parameters and analyzed D1
core protein in one year old plants of Jatropha curcus under different
light regimes (10–1200 μmol m–2 s–1)
in sun and shade plants. Chl a fluorescence provides insights into the
responses of the photosynthetic system to increasing irradiance. Total
Chl content was 1.43 and 0.61 mg/g-1 FM for shade and sun
exposed plants respectively. The effective quantum yield (ΔF/Fm')
of the sun plants was lower as compared to shade plants but the amount
of the D1 core protein was higher in plants grown under high light
intensity. A decrease in ΔF/Fm' indicates down regulation of
photosynthesis or photoinhibition. D1 protein is the membrane protein
complex of the PSII reaction centre. The degradation of D1 protein may
regulate the functioning of the PSII repair cycle under photoinhibitory
conditions. It has been shown that low-light grown or shade plants are
more susceptible to photoinhibition than high light or sun plants. This
higher susceptibility is accompanied by slow degradation of damaged D1
protein. High light intensity or exposure to photooxidation leads to
the irreversible damage in photosynthetic performance and consequently
has an overall inhibitory effect on crop productivity.
Key words: Chlorophyll a
fluorescence, D1 protein, Jatropha, Light, Photosystem II, Proline
