Disintegration of clonal connections in Solidago altissima (Compositae)

Abstract

determine if sloughing in the presence of Eurosta was the rule, we examined four clones grown under greenhouse conditions and five clones excavated in the field using a high-power water jet to uncover the underground rhizomes. The combined population of the McCrea and Abrahamson work and this study confirmed their findings-that rhizomal connection was significantly more likely to disintegrate ("slough") in the presence of galls. However, individual clones showed great variability in this trait, with some clones even being more likely to slough ungalled ramets than galled ramets. Whether or not galls were present, ramets which were shorter, slower growing, and slower to senesce were more likely to be sloughed. One greenhouse clone was distinguished by a hypersensitive, necrotic reaction to oviposition which showed strong correlation with sloughing. Though there is great variability in response, overall, the presence of galls causes more sloughing and further study is needed to see if this impacts the long-term fitness of the clone. We speculate that plant hormones may play a role in the occurrence of sloughing.