|Freeman, Thomas - NORTH DAKOTA STATE UNIV.|
Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 28, 1998
Publication Date: N/A
Technical Abstract: Potato tuber (Solanum tuberosum L.) periderm maturation is an important physiological process that directly affects the susceptibility of tubers to costly skinning-type wounds at harvest. We have identified the specific types of cells and cellular changes associated with susceptibility and resistance to tuber skinning in immature and mature tubers respectively. Epifluorescent microscopic examination of immature tuber periderm (phellem, phellogen and phelloderm cells) from several genetically diverse cultivars has shown that the cellular damage resulting from skinning injury (separation of phellem tissues from the tuber) occurs within the phellogen, a meristematic layer of cells located between the phellem (skin) and the phelloderm. Skinning results in the fracture of radial phellogen cell walls. As the tuber periderm matures and skinning resistance develops, the layer of phellogen cells become inactive and the connective radial cell walls of the phellogen become more resistant to fracture. Ultrastructural studies of immature tuber periderm show that radial walls of active phellogen cells are thin and fragile. During periderm maturation, the phellogen cell walls thicken and the radial walls take on a serpentine-like curvature as they strengthen and become resistant to fracture. The inner tangential walls of the layer of phellem cells that adjoin the phellogen become laminated with suberin aliphatics upon maturation, but unlike all other phellem cells these cell walls appear to possess little or no suberin phenolics.