Drought stress response in Jatropha curcas: Growth and physiology

Abstract

a b s t r a c tTolerance to drought remains poorly described for Jatropha curcas accessions from different geographical and climatic origins. To address this issue we studied the response of two J. curcas accessions, one from Indonesia (wet tropical climate) and the other from Cape Verde islands (semi-arid climate). Potted seedlings (with 71 days) of both accessions were subjected to continuous well watered conditions (control) or to a drought stress period followed by re-watering. To mimic natural conditions in which drought stress develops gradually, stress was imposed progressively by reducing irrigation (10% reduction every 2 days, on a weight base), for a period of 28 days, until a field capacity of 15% (maximum stress) was achieved, followed by one week under well-watered conditions. We measured soil and plant water status, growth and biomass partitioning, leaf morphology, leaf gas exchange and chlorophyll a fluorescence. Both accessions maintained high leaf relative water content (70-80%) even at maximum stress. Net photosynthesis (A n ) was not affected by mild to moderate stress but it abruptly dropped at severe stress. This was due to reduced stomatal conductance, which showed earlier decline than A n . Plant growth (stem elongation, leaf emergence and total leaf area) was reduced, minimizing water loss, but no significant differences were found between accessions. Drought stress did not reduce chlorophyll contents but led to reduced chlorophyll a/b. Both accessions showed fast recovery of both stomatal and photochemical parameters suggesting a good tolerance to water stress. Both J. curcas accessions showed a-dehydrationavoidant behaviour, presenting a typical water saving strategy due to strict stomatal regulation, regardless of their provenance.

Leaf gas exchange and biomass partitioning in Jatropha curcas L. young plants subjected to flooding and drought stresses

“…As opposed to water loss reduction, stomatal closure also reduces the carbon assimilation, thereby causing reduced photosynthetic rate (Chaves et al, 2002). The positive relationship of variables A and E in comparison with gs, in J. curcas specimens subjected to drought and flooding treatments indicates that stomatal closure may be the major limiting factor of these variables (Cornic, 2000;Sapeta et al, 2013;Silva et al, 2010). This interaction between gs and E, shows the importance of controlling stomatal movement (opening and closing), in plants adapted to stress condition, as occured in J. curcas plants under water deficit, allowing the plant to maintain a high WUE (Naves- Barbiero et al, 2000;Yang et al, 2005).…”

Morphophysiological changes in young plants of Jatropha curcas L. (Euphorbiaceae) subjected to water stress and recovery

“…is an oilseed species, which, despite showing a strong capacity for survival and recovery from water stressed conditions (King et al, 2009;Wang et al, 2011;Verma et al, 2012), has shown negative responses to water deficit in reduced growth and biomass production (Fini et al, 2013;Sapeta et al, 2013). The attractive characteristics of J. curcas include its expected lifespan of 50 years and its broad climatic tolerance, covering zones with annual precipitation between 250 and 1200 mm (Achten et al, 2008).…”

The relationship between succulence and shoot biomass differences according to nutritional status in Jatropha curcas L.

“…Nevertheless, in the case of J. curcas, this strategy still needs experimental verification. Succulence is a plant characteristic with clear ecophysiological implications (Mantovani, 1999;Mwine and Van Damme, 2011), which in J. curcas plants, until now, has been mainly explored in in relation to its adaptation to environments characterized by water deficit or soil salinity (Maes et al, 2009;Arcoverde et al, 2011;Díaz-López et al, 2012;Rodrigues et al, 2013;Sapeta et al, 2013).…”