Aging and Mitochondrial Development in Potato Tuber Tissue

Abstract

Respiratory activity of mitochondria isolated from fresh and aged potato tuber tissue has been determined. No significant change in activity of the particles (expressed per unit N) was observed as a result of aging. However, the yield of mitochondrial material increased with aging. It has been suggested that the commonly observed stimulation of respiration that accompanies aging of potato tissue can be attributed largely to an inerease in the mitochondrial population rather than to a stimulation of the particles per se, and that this increase results from a fission of pre‐existing mitochondria. The respiratory activity of mitochondria isolated from unaged tissue was found to decline following storage of the tubers in the cold for extended periods. This decline was attributed to a loss of cristae structure in the particles, as observed microscopically. The possibility that this reduction in structural organization might be associated with changes in the state of dormancy of the tissue was considered.

Phospholipid Synthesis in Aging Potato Tuber Tissue

“…Their work with tissue slices and with isolated cell fractions suggested that during aerobic incubation, there was a metabolismdependent modification of the mitochondrial respiratory chain. Evidence for an increase in the number of mitochondria during aging of potato disks was reported by Lee and Chasson (24, 25) and Verleur et al (34). Furthermore, in general an increase in the number of subcellular organelles is accompanied by a large increase in respiration.…”

Membrane Transformations in Aging Potato Tuber Slices

“…Synthesis of mitochondria during aging has been observed by several workers (2,15,25). It was found that after 24 hr of aging there was an increase in the population of mitochondria without any change in their specific enzymatic activity, and this increase was used to explain the respiratory increase in aged slices.…”

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ABSTRACTWhen potato tuber slices (Solanum tuberosum L.) Leaver and Key (14), and others support the derepression hypothesis.Evidence for mitochondrial biogenesis in aging root and tuber slices has been presented by several workers (1,2,6,15,23,25). In all these cases, tissue slices were aged for at least 24 hr before a mitochondrial increase was demonstrated.

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Relationship between Protein Synthesis in Tuber Discs and the Protein Synthetic Activity of a Cell-Free Preparation

“…increase in the aniounts of other elizyvnes ( 10,23,29). increase in mitochondrial numbers (17,18), svnthesis of cell xvall iiiaterials (20) and RNA synthesis (6,15). The use of specific inhibitors has indicated that these events are correlated with renewed protein synthesis (6,10) and soniie of theni at least are affected by knoxvn groxvtli liormones (9,29) notably indolyl-3-acetic acid and gibberellic acid.…”