Photosynthetic gas exchange, chlorophyll fuorescence, antioxidant enzymes, and growth responses of Jatropha curcas during soil fooding

Abstract

Te response of chlorophyll fuorescence, photosynthetic CO 2 assimilation (PN), stomatal conductance (gs), electrolyteleakage, and transpiration (E) was observed in Jatropha curcas seedlings subjected to soil fooding. A strong reduction in growth, leaf-area expansion (64%), and stomatal conductance (45%) impaired photosynthetic CO 2 assimilation (66%), which eventually reducedbiomass yield. Te ratio between variable-to-initial chlorophyll fuorescence (Fv/Fo) and the maximum quantum yield efciency of thephotosystem II (Fv/Fm) was used to explore damage associated with the functioning of the photosynthetic apparatus. A strong, non-linear correlation between physiological parameters and soil fooding duration was found. Our study primarily revealed consequencesof epigenetics, i.e. stagnant soil fooding, which afected growth, development, and performance of Jatropha curcas signifcantly. Teactivities of catalase (CAT), ascorbate peroxidase (APx), glutathione reductase (GR), and glutathione peroxidase (GPx) in leavesincreased, implying an integrated pathway involving CAT, APx, GR, and GPx for protection against the detrimental efects of reactiveoxygen species (ROS) during soil fooding.