Here we examined the response mechanisms and the strategies adopted to cope with drought stress in
Jatropha curcas L. Response mechanisms to water stress were explored in three different accessions (from
Brazil, Tanzania and Suriname) of J. curcas in terms of water and osmotic relations, gas exchange, PSII
photochemistry, and growth performances. Plants were exposed to 18 days of water stress (irrigation was
kept at 20% of water holding capacity) followed by 13 days of relief from stress. J. curcas withstands
drought stress with a drought-avoidance mechanism through a water saving strategy. These responses
include selective abscission of leaves, and marked decreases in net photosynthetic rates and water use
efficiency. This allows plants to maintain an “above-lethal” water potential during stress, and to recover
net assimilation rate promptly when water availability to the roots is resumed. The Suriname accession
displayed greater reductions in net photosynthesis, maximal efficiency of PSII photochemistry (Fv/Fm),
total leaf area and plant dry weight, as compared with both Tanzania and, particularly, the Brazil
accession, during drought stress. Impairment of PSII photochemistry was also observed in the Suriname
accession at the end of the relief period. Water-stressed J. curcas, irrespective of seed source, was capable
to recover net photosynthesis to the level of the well watered counterparts by the end of the relief
period. Our data allow to conclude that J. curcas may survive to drought spells of moderate intensities
but, at the same time pose serious concerns for its profitable cultivation in arid/semi-arid regions
worldwide.