ARS | Publication request: Response of Arundo Donax L. (Giant Reed) To Leaf Damage and Partial Defoliation

Submitted to: Journal of Freshwater Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 16, 2011
Publication Date: March 1, 2012
Citation: Spencer, D.F. 2012. Response of Arundo Donax L. (Giant Reed) To Leaf Damage and Partial Defoliation. Journal of Freshwater Ecology. 27:77-87. DOI:10.1080/02705060.2011.615523.

Interpretive Summary: Giant reed (Arundo donax L.) occurs throughout the southern half of the US from California to Maryland. It is considered an invasive plant in some parts of this range but not others. Giant reed often grows in habitats where it may be damaged by flooding. Previous researchers have found that plants may respond differently to leaf and stem damage. To understand how giant reed successfully invades new habitats, we performed experiments to determine the effect that leaf damage or complete removal of all the leaves on a stem would have on the growth of that stem. We also performed an experiment to determine if partial leaf damage would influence the photosynthetic rate of the damaged leaf and nearby leaves. We found that stem and leaf growth rates were not affected by leaf damage or removal. We also found that damaging a single leaf did not alter its photosynthetic rate or the photosynthetic rates of nearby leaves. These findings suggest that moderate to low levels of leaf and stem damage may not reduce giant reed’s persistence in a particular habitat.

Technical Abstract: Arundo donax (giant reed) is a tall clonal invasive grass which has impacted many riparian ecosystems in the U.S. 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 thus may not reduce A. donax persistence in a particular habitat.