Endogenous ethylene formation and the development of the alternative pathway in potato tuber discs

Abstract

Callus‐forming discs from potato ( Solanum tuberosum L. cv. Bintje) tubers grown on a nutrient medium containing an auxin and a cytokinin show both a higher ethylene formation and a higher capacity of the mitochondrial alternative pathway than nongrowing discs (on the same medium without auxin and cytokinin). Addition of 1‐ami‐nocyclopropane‐1‐carboxylic acid (ACC) to the nutrient medium of non‐growing discs results in an enhancement of the ethylene formation as well as the alternative pathway capacity. In callus‐forming tissue, the levels of both these parameters can be suppressed by adding aminoethoxyvinylglycine (AVG) to the nutrient medium without affecting growth. The effects on state 3‐respiration of ACC (increase) and AVG (decrease) are relatively small. These results suggest that the alternative pathway capacity is controlled to a considerable extent by the endogenous ethylene formation of the tissues.