Comparison of achene characteristics within and among diploid and tetraploid clones of Solidago flexicaulis and their significance in germination and resource allocation studies

Abstract

Achene characteristics were examined within clones, among clones of a cytotype, and between the diploid and tetraploid cytotypes of Solidago flexicaulis. The pattern of intraclonal variation was similar in each of the three diploid and five tetraploid clones. In each of the clones, embryo weight increased with increasing achene weight and the number of days taken to germinate increased with increasing pericarp weight. Other significant correlations were not consistent among all clones. Generally, clones of the same cytotype were more similar to each other than to clones of the other cytotype. Additionally, the characteristics were generally larger among the tetraploid than diploid clones. However, a trend in decreasing size from southwestern to southeastern Ontario was observed. With respect to most measured characteristics, tetraploid clones occurring just west of the Frontenac Axis were intermediate between tetraploid clones occurring farther southwest in Ontario and diploid clones occurring just east of the Frontenac Axis. In this study, knowledge of ploidy level was important not only with respect to the analyses performed but also with respect to the interpretation of results and the correct assessment of causal factors of observed patterns of variation. Thus, knowledge of ploidy level is especially important in comparative ecological studies involving patterns of resource allocation and germination rates.