Studies on Development of Cyanide-resistant Respiration in Potato Tuber Slices

Abstract

The respiratory changes wvhich take place in slices of tubers and tuberous roots have long been of interest to plant physiologists. As early as 1887, the wound respiration of white potato tubers was described (3), and since then many of the factors affecting this phenomenon have been analyzed (17). In recent years, the fact that the developed respiration is resistant to cyanide andl carbon monoxide has attracte(d special attention (18,25 The potato tuber slices, in which there is a striking change within one day, seemii ideally suited for further investigations on the problem of inhibitorresistant respiration. The plan of the present study has been to compare the respiratory mechanisms in freshly-cut and day-old slices, and to ascertain the conditions necessary for the development of the wound respiration. The w\ork has been carried on at two levels: with tissue slices and with isolated cell fractions. Oxygen uptake h1as been used as a measure of respiratory activity, and its coupling to phosphorylation estimated by following phosphate uptake. The respiratory components involved in hydrogen and electron transport have been exanmined by both enzymatic and spectrophotometric techniques. The evidence indicates that during the aerobic incubation of potato slices there is a metabolism-dependent moidification of the mitochondrial respiratory chain, prob-1

The Relation of Glucose Absorption to Respiration in Potato Slices

“…Potato slices, markedly cyanide-sensitive when freshly prepared, may become virtually cyanide-resistant in a day (7,14). By contrast, malonate-resistant fresh potato disks normally become increasingly malonate-sensitive with time (10,19).…”

The Respiratory System of Rhodotorula glutinis II. Mechanism of Inhibitor Tolerant Respiration

“…In the case of R. glutinis, the inhibitors appear to exert their action on the normal respiratory chain, thereby resulting in the operation of a compensatory respiratory system. Our data suiggest that the cyanide tolerant electron chain is nonphosphorylative and thus analagous to the situiation in the mitochondria isolated from the skunk cabbage spadix and aged potato slices where cyanide inhibits oxidative phosphorylation but has no effect on respiration (3,5).…”

Ascorbic acid oxidase of Myrothecium verrucaria

“…In particular, the enzyme in its native and extracted state seemed to be about equally susceptible to inactivation. This is of interest since Honda (12) found no reaction inactivation of the wall-localized oxidase in barley roots. The barley enzyme was inactivated in vitro.…”