Inter-Conversion of carbohydrate reserves from pollen maturation to rehydration in a chili pepper

Abstract

Carbohydrate metabolism is critical for male fertility. Carbohydrate reserves (soluble sugars and starch) were quantified in three advanced stages of pollen development, from the final maturation to rehydration, in a chili pepper cultivar (Capsicum annuum L. cv. Calypso Red) with partially dehydrated pollen, to define possible carbohydrate inter-conversions. At the same time, the activity of soluble enzymes involved in sucrolysis and amylolysis were quantified to reveal potential metabolic pathways. The carbohydrates found (sucrose, glucose, fructose, and starch) apparently inter-convert. There would be a close relation between enzymatic activities and substrates, and the carbohydrate reserves could be key factors on the regulation of enzymatic activities. All the enzymes tested were active, although the relevance of each one changed along pollen maturation and rehydration, defining different profiles of enzymatic activities for each stage. Some usually neglected enzymes (e.g. soluble neutral invertase) have shown an important role in the stages analyzed, suggesting alternative processes to evaluate in the studies of male fertility control.