Effect of domestication on water transport in Jatropha curcas seedlings: Relevance of xylem vessels of organs and aquaporin activity in roots

Abstract

Plant domestication may lead to the suppression of attributes that enable survival in adverse environments. In this context, considering the scarcity of information on water transport in Jatropha curcas L., an experiment was conducted to compare the anatomical variables and hydraulic parameters of roots, stems, and leaves as well as the contribution of aquaporins in water transport of roots between wild and domesticated genotypes. Under irrigation, it was observed 10.2% larger xylem vessel diameters in roots but 7.9% and 11.3% smaller xylem vessel diameters in stems and leaves, respectively, of domesticated genotypes as compared to their wild counterparts. Overall, domestication resulted in 57.5% lower hydraulic resistivity in roots, 87.2% higher hydraulic resistivity in leaves, 22.4% higher vein length per leaf area, 10.5% lower net photosynthetic rate, 36.7% and 42.6% lower theoretical leaf area-specific hydraulic conductivity in roots and stems, respectively. Conversely, in domesticated genotypes, theoretical mass-specific hydraulic conductivity was respectively 58.4% and 57.7% higher in roots and stems. Furthermore, in these genotypes, the root volume was 13% smaller and the contribution of aquaporins to the hydraulic conductivity of roots was greater. In conclusion, domestication has driven the selection of genotypes with roots that are more efficient in conducting water through effects on the anatomy of xylem vessels and activity of aquaporins. However, leaves of such genotypes are more conservative in anatomical and photosynthetic terms. • Domestication of J. curcas resulte in water transport efficient genotypes. • Such efficiency resulted from aquaporin activity and from changes on xylem anatomy. • Domestication improved leaf water distribution, without changes on photosynthesis.