Soluble carbohydrates content in tomato pollen and its variations along and between blooming periods

The soluble carbohydrates content in the mature (starchless) pollen of the tomato (Solanum lycopersicum L.) cv. Platense was studied at several moments of the blooming period in two consecutive years. The aim of the analysis was to evaluate if the content of soluble carbohydrates is relatively constant or if it can fluctuate along the blooming period. No significant variations in pollen viability were recorded along each season. The soluble carbohydrates found and their concentrations can change significantly among samples, but the fluctuations observed did not follow a strongly definite pattern in any season. Reducing sugars predominated; small quantities of a phosphorylated sugar, UDP-glucose, and maltosaccharides were also recorded. The constant presence of maltosaccharides is a novel record for pollen. Sucrose was absent in one season, but present in the other, in low percentages in contrast to reducing sugars. Changes in the soluble carbohydrates content have been usually related with alterations in pollen fertility. However, there may be some flexibility in the metabolism of the pollen studied this time, at least within a certain range, which may allow constant adjustments to maintain acceptable levels of viability despite the variations in the carbohydrates concentrations.