Response of Arundo donax L. (giant reed) to leaf damage and partial defoliation

Arundo donax (giant reed) is a tall clonal invasive grass which has impacted many riparian ecosystems in the US. Experiments tested the hypotheses (1) that defoliation would affect A. donax stem growth and leaf production and (2) that leaf damage or removal would influence A. donax photosynthetic rates using a combination of field and laboratory settings. Leaf defoliation did not affect the height of stems or the number of leaves per stem for plants growing at a field site. Leaf damage did not influence the electron transport rate (ETR) for damaged or adjacent leaves, and defoliated stems maintained ETR which were similar to those of undamaged leaves. These findings suggest that moderate to low levels of leaf damage and/or defoliation alone may not significantly influence growth of A. donax stems and leaves and, therefore, may not reduce A. donax persistence in a particular habitat. Further, these results provide a benchmark against which to judge the effects of management approaches which affect A. donax...