TY - JOUR

T1 - Dissipation of excess photosynthetic energy contributes to salinity tolerance: A comparative study of salt-tolerant Ricinus communis and salt-sensitive Jatropha curcas

AU - Costa Lima Neto, Milton

AU - Moreira Lobo, Ana Karla

AU - Martins, Marcio Oliveira

AU - Fontenele, Adilton Vasconcelos

AU - Silveira, Joaquim Albenisio Gomes

PY - 2014/1/1

Y1 - 2014/1/1

N2 - The relationships between salt tolerance and photosynthetic mechanisms of excess energy dissipation were assessed using two species that exhibit contrasting responses to salinity, Ricinus communis (tolerant) and Jatropha curcas (sensitive). The salt tolerance of R. communis was indicated by unchanged electrolyte leakage (cellular integrity) and dry weight in leaves, whereas these parameters were greatly affected in J. curcas. The leaf Na+ content was similar in both species. Photosynthesis was intensely decreased in both species, but the reduction was more pronounced in J. curcas. In this species biochemical limitations in photosynthesis were more prominent, as indicated by increased Ci values and decreased Rubisco activity. Salinity decreased both the Vcmax (in vivo Rubisco activity) and Jmax (maximum electron transport rate) more significantly in J. curcas. The higher tolerance in R. communis was positively associated with higher photorespiratory activity, nitrate assimilation and higher cyclic electron flow. The high activity of these alternative electron sinks in R. communis was closely associated with a more efficient photoprotection mechanism. In conclusion, salt tolerance in R. communis, compared with J. curcas, is related to higher electron partitioning from the photosynthetic electron transport chain to alternative sinks.

AB - The relationships between salt tolerance and photosynthetic mechanisms of excess energy dissipation were assessed using two species that exhibit contrasting responses to salinity, Ricinus communis (tolerant) and Jatropha curcas (sensitive). The salt tolerance of R. communis was indicated by unchanged electrolyte leakage (cellular integrity) and dry weight in leaves, whereas these parameters were greatly affected in J. curcas. The leaf Na+ content was similar in both species. Photosynthesis was intensely decreased in both species, but the reduction was more pronounced in J. curcas. In this species biochemical limitations in photosynthesis were more prominent, as indicated by increased Ci values and decreased Rubisco activity. Salinity decreased both the Vcmax (in vivo Rubisco activity) and Jmax (maximum electron transport rate) more significantly in J. curcas. The higher tolerance in R. communis was positively associated with higher photorespiratory activity, nitrate assimilation and higher cyclic electron flow. The high activity of these alternative electron sinks in R. communis was closely associated with a more efficient photoprotection mechanism. In conclusion, salt tolerance in R. communis, compared with J. curcas, is related to higher electron partitioning from the photosynthetic electron transport chain to alternative sinks.

KW - Castor bean

KW - Physic nut

KW - Photoprotection

KW - Photosynthesis

KW - Salt stress

U2 - 10.1016/j.jplph.2013.09.002

DO - 10.1016/j.jplph.2013.09.002

M3 - Journal article

VL - 171

SP - 23

EP - 30

JO - Journal of Plant Physiology

JF - Journal of Plant Physiology

SN - 0176-1617

IS - 1

ER -