Sumnmnary. Ontogenic changes in respiratory pathways of skinls of detached apple fruits were measuired duiring a 4 month period. ReEtults showsed that an increase in pentose pathway occuirred with increasing senescence in this tisstue. V-ariation in temperature at any given age did not result in an alteratioin of the C,1C, ratio. atory determinatioins %-ere removedl from storage and tisedl 1 houir after warming to room temperatulre. Twice cl(iring storage a larger sample was removed aind heldl for I week at 21°. Respiratory determinations were ma(le on these apples dutring this holding period.

Vegetable foods are drastically softened by high doses of radiation. Irradiated plant tissues also leach calcium which has been associated with this softening. To investigate the relation of this calcium to cell wall polysaccharide degradation, irradiated carrots were fractionated into their constituent polysaccharides and analyzed for calcium. Irradiation brought about a redistribution of cell wall polysaccharides which is generally consistent with solubilization. Calcium was associated with the most insoluble polysaccharide fraction. It was concluded that the observed release of calcium is either not associated with the cell wall or is associated only with the weakly bound calcium and probably not in itself responsible for the softening process.Texture in vegetable foods is drastically affected by high doses of 7 radiation (Glegg et al., 1956;Roberts and Proctor, 1955). This softening is apparently the result of alterations in wall structure and cohesion (Massey and Faust, 1969;Romani, 1967;Sterling, 1963). There is considerable evidence as to the importance of calcium pectate on cell wall rigidity (Cormack, 1965;

No abstract