Regulation of root respiration and sugar-mediated gene expression in plants.

摘要

The respiration rate of plant tissues is related to both substrate supply and demand for respiratory energy. At the biochemical level, it is considered to be regulated by the supply of adenosine diphosphate. In the whole plants, respiration rate iscorrelated with carbohydrate content suggesting control by substrates. There is evidence to support both hypotheses, and they can be reconciled if the capacity of tissues for respiration can alter within a few hours and sucrose can control that capacity.Supplying exogenous sugars to the starved tissue not only increases the rate of respiration of that tissue but also leads to induction of enzymes which are involved in reversing the carbohydrate starvation-induced effects in plants. Expression of proteins and metabolic systems may be under the direct or indirect control of sugar. Sucrose or some product of its metabolism can control gene expression of these proteins, probably by increasing transcription.