Differential Responses of Jatropha Species on Growth and Physiological Parameters to Salinity Stress at Seedling Plant Stage

Abstract

The effect of salinity on Jatropha curcas (J. curcas), native to nonsaline humid areas, and Jatropha cinerea (J. cinerea), native to saline dry areas, was compared to assess the potential of cultivating J. curcas for biodiesel production in saline soils that are not suitable for food production. Growth parameters, water relations, chlorophyll content, and stomatal conductance of both species under salinity were measured. Dry weight of both species decreased with increasing concentrations of salt; however, both species can grow at salinities up to ˜100 mM sodium chloride (NaCl). Decline of stomatal conductance was one of the main factors causing reduction in growth of Jatropha spp. Growth of J. curcas was inhibited more than that of J. cinerea by decline in growth parameters and chlorophyll content, but J. curcas shows sufficient hardiness to be cultivated in moderately saline soils with more favorable water relations.

Keywords:

• Growth analysis
• Jatropha curcas
• salinity
• stomatal conductance

Acknowledgments

The authors thank personnel at CIBNOR. Carmen Mercado and Lidia Hirales assisted with laboratory procedures; Luis Landa, Miguel Díaz, and Pedro Luna assisted in the field; Ira Fogel provided important editorial advice; and Bernardo Murillo helped with statistical procedures. Funding was provided by CIBNOR. M. H. is a recipient of a doctoral grant from the Secretaría de Relaciones Exteriores of Mexico.