Antioxidative and osmorregulatory responses of Jatropha curcas to water stress are genotype dependent

Abstract

Jatropha curcas L., Euphorbiaceae, is an undomesticated species noted for its high oil content of the seed (17.5 - 41.6%), which can be used to produce biodiesel, among other products. The objective of this study was to evaluate the behavior of nine Brazilian genotypes of J. curcas under the effect of water deficit. Seedlings of these genotypes (CNPAE 121, 124, 148, 168, 222, 215, 226, 298 and 299) were submitted to two irrigation regimes for 42 days: controlled irrigation (100% of tank capacity, TC) and water stress (WS, 50% TC). The foliar content of proline increased 56% on average in water stressed plants compared to the control plants. Water deficit-induced decreases of 62, 112, 78 and 23% in photosynthetic rate, stomatal conductance, transpiration rate and internal to atmospheric CO2 concentration ratio (Ci/Ca), respectively, were observed. Foliar activities of dismutase superoxide, guaiacol peroxidase and catalase increased in the stressed in comparison with the control plants. The genotypes CNPAE-148 and 222 were considered tolerant, as indicated by strong water conservation and significant increase in the activity of antioxidant enzymes when subjected to water stress.