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Redox regulation and storage processes during maturation in kernels of Triticum durum
Laura De Gara, Maria C. de Pinto, Vita M. C. Moliterni and Maria G. D'Egidio
Journal of Experimental Botany
Vol. 54, No. 381 (January 2003), pp. 249-258
Published by: Oxford University Press
Stable URL: http://www.jstor.org/stable/23697749
Page Count: 10
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Metabolic changes during the development and maturation of Triticum durum Desf. (L.) kernels were studied, with particular emphasis on changes in the redox state of ascorbate and glutathione, as well as in the activities of the enzymes responsible for the recycling of their oxidized forms (ascorbic free radical reductase, EC 22.214.171.124; dehydroascorbate reductase, EC 126.96.36.199; glutathione reductase, EC 188.8.131.52) and for detoxification or utilization of hydrogen peroxide (ascorbate peroxidase, EC 184.108.40.206; catalase, EC 220.127.116.11). In parallel with this analysis, the production and storage of reserve compounds was studied, in particular, soluble carbohydrates (mono- di-saccharides and fructans) and the transition from sulphydryl groups to disulphide bridges into proteins. The results indicate that both the activities of the ascorbate and glutathione redox enzymes and that of catalase are high before the start of drying maturation, after which they decrease. Moreover, analysis of the redox state of ascorbate and glutathione pairs and the sulphydryl to disulphide transition into proteins suggests that these three parameters are tightly related during kernel maturation, thus confirming the involvement of the two redox pairs in protein maturation as well as in protection against reactive oxygen species. The physiological implications of the changes in cellular redox state and in soluble carbohydrates for the acquisition of desiccation tolerance and reaching the resting phase in orthodox seeds are also discussed.
Journal of Experimental Botany © 2003 Oxford University Press