Transverse slices of green banana fruit (2-6 mm thick) exhibit after cutting an initial burst of respiration which largely subsides within 2 hr, and a broad peak of "induced" respiration at 15-20 hr. Respiration subsequently declines and within 4 days stabilizes at a rate two to three and a half times that of matched, intact fruits. Ripening of the slices occurs naturally within 4 weeks after cutting; it may also be induced at any time by treating with ethylene. In all attributes studied (sensitivity to ethylene, respiratory climacteric, respiratory quotient, peel colour changes, starch to sugar conversion, softening, and aroma development), the slices are comparable to whole fruit. Inhibitors or metabolites may be introduced into the slices by vacuum infiltration. The slices provide a suitable model system for studying the biochemistry of fruit ripening at the tissue level.
Transverse slices of green banana fruit were vacuum· infiltrated with aqueous solutions of 24 potential inhibitors of protein synthesis, respiration, or ethylene production. The effects of these compounds were examined in the absence or presence of 10 p.p.m. ethylene. Of the compounds which produced marked effects mono· fiuoroacetate, 4·hydroxy·2·oxoglutarate (HKG), KCN, and cycloheximide were examined in more detail.Monofiuoroacetate (1 and 2 X 10-2M) and cycloheximide (1 and 2I-'g/ml) almost eliminated the peaks of induced respiration and ethylene production, almost eliminated the respiratory response to added ethylene, and prevented normal ripening. Ethylene production by slices treated with the inhibitors rose within a few hours after treatment to steady levels considerably above the preclimacteric rates of untreated slices, possibly as a result of cell damage. KCN at 5 X 10-2M caused breakdown of the tissue. At 1 and 2·5 X 10-2M, KCN almost eliminated the peak of induced ethylene production, but only delayed the peak of induced respira. tion and retarded ripening in both ethylene. treated and ungassed slices. Before the resumption of a normal ripening pattern in slices treated with KCN ethylene pro· duction declined to normal preclimacteric rates. HKG at 3 X lO-2M eliminated the induced rise in ethylene production, delayed the peak of induced respiration, and reduced respiration in ethylene-treated slices but did not affect ripening. There is evidence that banana tissue may metabolize HKG and KCN.
AbsirackThe apparent molecular weight of three soluble polysaccharide fractions of winged bean seeds (Psophocarpru tetragonolobus [L.]) were investigated using gel filtration chromatography. Winged bean polysaccharides tend to be aggregated in water solution (molecular weight of 1 million plus), but dissociate in salt solution into a mixture containing components with an essentially continuous distribution of molecular weight (1 million to 1000). The degree of aggregation and disaggregation, and the range of molecular weight in solution, depends to some extent on the method of isolation and the method of analysis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.