Respiratory control, oxidative phosphorylation, respiration, rate of ATP hydrolysis, and ethylene evolution in subcellular particulate fractions from cotyledons of germinating seedlings

Abstract

Respiration rates, with α-ketoglutarate or succinate as substrate, of mitochondria isolated from bean cotyledons at various stages during seedling germination were found to follow the rate of mitochondrial ATP hydrolysis. Respiration was maximum at 7 days after planting, and ATP hydrolysis was maximum at 5 days after planting. Cotyledon mitochondria exhibited respiratory control in the early stages of germination, but all control was lost by the 3rd day. ADP control of respiration was again established by day 6, was maximum at day 7, and had disappeared by day 10.Ethylene production from whole cotyledons at various stages during seedling germination followed ethylene production from a subcellular particulate fraction of these cotyledons. Certain parallels can be drawn between ethylene evolution, ATP hydrolysis, and respiratory control. The possible influence of each parameter on the others is discussed.