Changing respiratory pathways in potato tuber slices

Abstract

The test solutions wvere of two formulations, for controls (C), and for malonate treatments (M).

The Relation of Glucose Absorption to Respiration in Potato Slices

“…By contrast, malonate-resistant fresh potato disks normally become increasingly malonate-sensitive with time (10,19). However, when storage organ slices are aged in bicarbonate under 5 to 10 % CO2 in air, the respiration rises as normally but remains malonate-resistant (11).…”

“…One way to estimate and characterize respiratory activity is to observe the utilization and disposition of radioactive substrate provided exogenously at levels sufficiently low so that hopefully the metabolite provided serves to label the endogenous metabolic pool without significantly altering the latter. It was early noted that when fresh and aged potato slices were compared with respect to the utilization of C14-labeled glucose, the evolution of C1402 differed very much more markedly than did gross glucose absorption (10,19). Since a pronounced enhancement of salt absorbing capacity is known to accompany the respiratory rise which attends aging (12,13), the question arose as to whether apparent differences in glucose utilization reflected distinctions related to glucose absorption.…”

The Effect of Light upon Development in Potato Tissue Slices

“…Ap Rees and Beevers (1), who suggested that pentose phosphate metabolism is largely responsible for the respiratory increase, allowed light from normal laboratory conditions to strike the aging slices. Romberger and Norton (12), on the other hand, indicated that culturing (aging) was carried out in the dark and have interpreted their results to indicate that the tricarboxylic acid cycle becomes enhanced with aging. The latter conclusions were also reached by Laties (8), although light conditions were not reported.…”

The Onset of Tricarboxylic Acid Cycle Activity with Aging in Potato Slices

“…\Vhen inhibitioni of C-6 release by-malonate is first manifest, the evolution of C"4O. fromii C-1 labelecl glucose becomes malonate-sensitive for the first time (22). C) Agedl slices presente(l xvith uniformly labeledI glucose-Cl accumlulate labeled succinate in the presence of malonate.…”

“…A) While a variable modlicum of fresh slice respiration nlay prove malonate-sensitive, fresh tissue respiration is predominantly malonate-resistant. By contrast, the respiratory increment which arises Nvith aging is alimlost 1 Received Oct. 16, 1963. totally malonate sensitive (22). B) Fresh slices release C-1 of 1-C14 labeledl glucose as CO., but fail to release radioactive CO., fronm 6-Cl4 labeled glucose.…”