Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 26, 2001
Publication Date: N/A
Technical Abstract: Skinning of potato tubers results in hundreds of millions of dollars of losses to producers every year. Potatoes are susceptible to skinning when they are harvested before periderm maturation (skin-set) is complete. Research in our laboratory has shown that skin-set is dependent on changes in the cell wall structure of the meristematic cell layer of the periderm (phellogen). In particular, radial walls of the phellogen cells thicken during skin-set. The biochemistry of these changes in wall structure are poorly understood. Our research indicates that an increase in un-esterified (acidic) pectins in phellogen cell walls accompanies maturation of the periderm. Staining with ruthenium red indicates that the phellogen cell walls of immature periderm include esterified pectins, but are lacking in un-esterified pectins. Periderm maturation is accompanied by an increase in un-esterified pectins in phellogen walls. Although peroxidases are involved in the cross-linking of many polymers in the cell wall, we could not detect any changes in peroxidase activity (in situ) in phellogen walls that accompanied maturation of the periderm. Development of wound periderm differs from native periderm, in that wound periderm maturation is not accompanied by an increase in un-esterified pectins in the phellogen cell walls. We are continuing to investigate the biochemical changes in phellogen cell walls associated with skin-set development.