Photosynthesis and fluorescence responses of Jatropha curcas to chilling and freezing stress during early vegetative stages
Jatropha curcas is a promissory species for biodiesel production. Chilling and freezing stress are major environmental constraints for its establishment as a result of the injury provoked on leaf photosynthetic apparatus. This study is aimed at evaluating the impact of chilling [40h at 4°C] and freezing [2h at -1, -2 and -3°C] on maximum leaf photosynthesis [Amax], in relation to stomatal conductance [gs] and photochemical activity. Two similar experiments were conducted in pots outdoors; treatments were performed in climate chambers at the stage of four expanded leaves per plant, and then returned outdoors. Leaf gas exchange, water status and fluorescence variables were measured at 1 and 30 days after the end of the treatments [DAT]. At 1 DAT, Amax and gs were reduced up to 75 percent and 100 percent in chilling and freezing treatments, respectively. However, the intercellular CO2 concentration [Ci] showed an inverse pattern, discarding a determinant role in Amax reductions. A lower efficiency electron use for photosynthesis was detected for plants subjected to chilling and freezing stress. The potential efficiency of PSII [Fv/Fm], chlorophyll content [Chl] and relative water content [RWC] were only affected by the lowest freezing treatments, while chilling and intermediate freezing plants showed an increase of the non photochemical quenching [NPQ]. Leaf death occurred in the lowest freezing treatments, while several residual effects on Amax, gs and electron transport rate [ETR] were also observed at 30 DAT in the survival plants. This work sheds light on the determinant processes involved in the depletion of photosynthesis by chilling and freezing injuries, revealing that low temperatures have persistent and detrimental effects on J. curcas crop establishment.
| Main Authors: | , , , , , |
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| Format: | Texto biblioteca |
| Language: | spa |
| Subjects: | BIODIESEL, BIOFUEL, CHILLING, CONCENTRATION [COMPOSITION], ENERGY EFFICIENCY, FLUORESCENCE, FREEZING, JATROPHA CURCAS, LOW TEMPERATURE, PERSISTENCE, PHOTOCHEMISTRY, PHOTOSYNTHESIS, PLANT COMMUNITY, STOMATAL CONDUCTANCE, , |
| Online Access: | http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=47089 http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber= |
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