Resource and Pollen Limitation in Hyacinthoides
non-scripta: Impacts upon Fruit and Seed
Development, plus Seed Maturation Pattern.

Abstract

Resource limitation, pollen quality (involving self- or outcross-pollen) and pollen quantity limitations are known to affect seed development by increasing ovule abortion and reducing ovule fertilisation. It is therefore important to fully understand pollen and resource limitations as they have a significant effect upon plant fitness. H. non-scripta has linearly arranged ovules, and produces a general non-random seed maturation pattern, with increased seed development at the stylar end and increased seed abortion and unfertilised ovules at the basal end of the fruit. Although this pattern has been observed in many species, exploration of how resources and pollen quality and quantity influence the non-random seed maturation pattern has not before been performed. In this thesis I investigate the effects of additional resources and a range of pollen qualities and quantities upon fruit development, seed development and the seed maturation pattern. A stochastic simulation model is used to assess how resources and pollen may impact seed development in H. non-scripta. Simulations reveal increasing resources and pollen quality and quantity should increase fruit set, and seed development. Resource manipulations in the field had little effect on fruit set or seed development, although field pollen manipulations produced similar results to those expected. Seed expansion increased with pollen quantity and quality. It is found that the non-random seed maturation pattern may be partly due to resources allocated to ovules fertilised first, but fewer resources may be allocated to the most stylar ovules in the fruit. Additionally, the non-random seed maturation pattern is stronger under mixed pollen qualities. Furthermore, open pollination appears to be composed of large quantities of a balanced mixture of outcross- and self-pollen. Together, the findings suggest resources and pollen are very important factors influencing the fruit development, seed development, and the non-random seed maturation pattern in H. non-scripta, and should be studied in conjunction.