The Relationship between Transmitting Tissue, Pollen Tube, and Ovule Number: A Study across 10 Angiosperm Families

Abstract

In this study we quantified features of the transmitting tissue for a broad range of angiosperm species to compare these values to pollen tube number and ovule number. Pistils from 25 species, from 10 angiosperm families, including one monocotyledon, were serially sectioned at the base of the style, and the cellular and noncellular areas within the transmitting tissue were determined using an image analysis package. Transmitting tissue cell number and whole stylar area were also measured. Overall stylar structure and tissue areas were generally consistent within families but differed significantly among families. There was a positive overall relationship between quantity of transmitting tissue, pollen tube number, and ovule number. However, the ratio of transmitting tissue intercellular space to pollen tubes was ≤$$1.1\times 10^{2}$$ μm2/pollen tube for species with multiple ovules, whereas it ranged from 0.9 to $$22.6\times 10^{2}$$ μm2/pollen tube in species with one or two ovules, and for species with multiple ovules, the ratio of transmitting tissue cells to pollen tubes was lower than for species with few ovules. The results are discussed in terms of relative investment in seed production.