Does pollen abortion increase with plant age?

Abstract

The large tropical forest tree, Anacardium excelsum (Bertero & Balb. Ex Kunth) Skeels, of the family Anacardiaceae, was studied in Panama. Using Alexander's stain, which differentiates aborted and non-aborted pollen, the proportion of aborted pollen versus plant age, size variation in aborted and non-aborted pollen and pollen:ovule ratio were estimated. Aborted pollen was smaller than non-aborted pollen regardless of plant age. The proportion of aborted pollen varied from 15.8 to 54.7% showing a steady increase with plant age, and the pollen:ovule ratio also increased with age. These results support the qualitative prediction that pollen abortion gradually increases with ageing reflecting an increase in genetic load with age.