Many factors affect plants’ invasibility, including features of the novel community and of the plant itself. Exotic plants with greater genetic diversity or phenotypic plasticity are likely to be more successful invaders, especially under shifting environmental conditions. Celastrus orbiculatus (oriental bittersweet) is a liana whose density has reached invasive proportions in western North Carolina. Recent studies have tested bittersweet’s physiological responses to a range of light conditions. Using similar conditions to compare variation among both light levels and genotypes, site-specific plasticity was examined in this non-native liana. One prediction was that genotypes would respond differently to varying light conditions and that some populations would be more plastic than others. Shade cloth structures of varying light conditions were used to simulate light levels below mature, immature, or open tree canopies. Plants from three western North Carolina sites (50 genotypes each) were cloned 8 times to allow multiple clones to be exposed to different light conditions. Clones were grown for 8 weeks with height, leaf number, and leaf area measured after 0, 4, and 8 weeks. At the experiment’s conclusion, dry mass of leaves, stems, and roots was also assessed.
Results/Conclusions
Results showed different degrees of plasticity and patterns of resource allocation among populations. Significant varied effects were seen on stem, root, total mass, and leaf response to light treatments among populations. At the population level, these results could be attributable at the genetic level. Leaf, stem, root, and total mass varied significantly within light treatments at the individual level as well. A contrast of same genetic individuals within varying light levels could also be a variation of genetics. These traits could facilitate increased invasiveness by oriental bittersweet, and a better understanding of the relationship between genotype and environment could be used to control this invasive’s spread. As a result of the variation between populations and individuals a shift in adaptation could be seen from adult populations and seedlings.
