02493naa a2200289 a 450000100080000000500110000800800410001902200140006002400520007410000170012624501340014326000090027730000180028649000070030452016540031165000140196565000220197965000130200165000150201465000180202965300220204770000220206970000180209170000190210970000200212877300550214821325482021-06-30       2021    bl uuuu     u00u1 u    #d  a2662-25487 ahttps://doi.org/10.1007/s40502-021-00576-22DOI1 aGOMES, F. P.  aNocturnal acidification in leaves of two genotypes of Jatropha curcas L., subjected to soil water deficit.h[electronic resource]  c2021  ap. 220-230 26  v26  aJatropha curcas has been considered as a potential oil source for biodiesel production in tropical and subtropical areas. The relationships between water deficit-induced nocturnal acidification and leaf succulence, gas exchange rates and water relations in leaves of J. curcas were accessed in a greenhouse experiment. Two genotypes, from regions of Brazil with contrasting climate (CNPAE183, from a dry and hot tropical climate and CNPAE191, from a humid subtropical climate), were maintained under full irrigation or were subjected to water deficit for 49 days followed by recovery for 7 days. Leaf relative water content decreased with water deficit from 85.4 to 77.5%, in both genotypes. Pre-dawn leaf water potential decreased from - 0.5 MPa in irrigated plants - 1.0 MPa (in CNPAE183) and to - MPa (in CNPAE191). Slow and less intense decrease of leaf gas exchange in CNPAE191 than in CNPAE183 suggests a high effective water use under water deficit in the former. Leaf nocturnal acidification increased 4.3-fold in water deficit plants of both genotypes and a positive correlation between nocturnal acidification and leaf succulence, expressed as fresh mass per dry mass, was observed. Water deficit-induced nocturnal acid accumulation and a positive correlation between nocturnal acidification and leaf succulence were thoroughly demonstrated. While such nocturnal acidification may be related to osmotic adjustment, its correlation with leaf succulence suggests a weak CAM-cycling activity in leaves of J. curcas which, along with other water-conserving mechanisms, may help to explain the widely reported drought tolerance of this species.  aBioenergy  aDrought tolerance  aJatropha  aBioenergia  aEuphorbiaceae  aLeaf gas exchange1 aALMEIDA, A. F. de1 aMIELKE, M. S.1 aLAVIOLA, B. G.1 aSILVA, L. D. da  tPlant Physiology Reportsgv. 26, p. 220-230, 2021.