Effect of cadmium on resumption of respiration in cotyledons of germinating pea seeds.
Pea seeds (Pisum sativum L.) were germinated by soaking in H2O or 5 mM CdCl2 during a 5-day period. Enzyme activities involved in respiratory metabolism were studied in cotyledons. Mitochondrial cytochrome c oxidase and NADH- and succinate-cytochrome c reductase activities were inhibited by cadmium treatment. The effects of Cd were performed in vivo and in vitro allowing to distinguish between the direct inhibition of the enzyme activities and the influence on the same enzymes into the cell environment. However, Cd exposure stimulated an enzyme activity of fermentation and inhibited the capacity of the enzyme inactivator (alcohol dehydrogenase inactivator). Moreover, the enzyme activities of NAD(P)H-recycling dehydrogenases via secondary pentose phosphate pathway, glucose-6-phosphate- and 6-phosphogluconate-dehydrogenases, were enhanced in Cd-stressed seeds. These disturbances suggest that cadmium may inflict a serious injury on renewal of respiration. The findings will help clarify the overall mechanisms that underlie cadmium-mediated toxicity in germinating seeds.
Smiri
Moêz
M
Bio-Physiologie Cellulaires, Faculté des Sciences de Bizerte, 7021 Zarzouna, Tunisia. moez.smiri@scbiol.uhp-nancy.fr
Chaoui
Abdelilah
A
Rouhier
Nicolas
N
Gelhaye
Eric
E
Jacquot
Jean-Pierre
JP
El Ferjani
Ezzedine
E
D002104:Cadmium / Q000633:toxicity*; D019069:Cell Respiration / Q000187:drug effects; D018548:Cotyledon / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D004785:Environmental Pollutants / Q000633:toxicity*; D018525:Germination / Q000187:drug effects; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D018532:Pisum sativum / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010734:Phosphogluconate Dehydrogenase / Q000378:metabolism; D012639:Seeds / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D013384:Succinate Cytochrome c Oxidoreductase / Q000378:metabolism; D013997:Time Factors
D004785:Environmental Pollutants; D002104:Cadmium; D009243:NAD; D013384:Succinate Cytochrome c Oxidoreductase; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D003576:Electron Transport Complex IV