LE3 .A278 2008

2008

Good-Avila, Sara

Acadia University

Bachelor of Science

Honours

Biology

Biology

Amelanchier bartramiana (family Rosaceae) is reported to be a sexually reproductive but self-incompatible species in the northeastern United States. The objectives of this study were to characterize the breeding system of populations in northern New Brunswick and compare them to those in the US. Morphological characters including petal length, petiole length, angle of leaf base, and flower number per inflorescence were quantified and principal component analysis was used to compare populations in NB and the US. To assess the presence of self-incompatibility (SI) and the potential for apomixis, a full pollination study was conducted. Treatments included open and closed pollination controls, emasculation, self-pollination, and within and between population cross-pollinations. Apomixis was assessed using Herr’s protocol, where ovules were cleared and megagametophytes were counted. Principal component analysis indicated that fragmentation had little effect on species boundaries and that four hybrid individuals were included in the study. Pollination results revealed that fruit set was maximal after open pollination in two populations and near zero in closed pollination and self-pollination treatments, indicating that autogamy is rare. In the third population, seed set following cross-pollination within population was highest and again fruit was rarely set via self-pollination. Seed viability and abortion rates were low in all treatments, but abortion rates were higher in seeds produced via self-pollination. Sexuality was demonstrated in ovule observations, as only one megagametophyte per ovule was generally identified. It is concluded that A. bartramiana is sexually reproductive, partially self-incompatible, and that fragmentation due to physical separation has had little effect on morphological variation between populations.

The author retains copyright in this thesis. Any substantial copying or any other actions that exceed fair dealing or other exceptions in the Copyright Act require the permission of the author.

https://scholar.acadiau.ca/islandora/object/theses:538