Egelhoff, Rose (2014)
Chemical weapons? The effect of allelochemicals from the invasive grass Vulpia myuros on fungal colonization of Artemisia californica.
Bachelor of Arts, Pomona College, Biology.
Advisor: Frances Hanzawa.
Allelopathic exudates from one plant may inhibit germination and stunt growth of competing plants, but can also interfere with competitors indirectly. Recent studies have shown that allelochemicals from certain invasive species disrupt the mycorrhizal networks of native plants. Vulpia myuros, an invasive grass in coastal sage scrub (CSS) communities, is known to contain allelopathic chemicals that suppress root and shoot growth in several agricultural species. I studied the possibility that Vulpia allelochemicals decrease mycorrhizal colonization rates of Artemisia californica, a co-dominant CSS shrub by measuring arbuscular mycorrhizal (AMF) colonization rates and infectivity of A. californica rhizosphere AMF communities in the presence or absence of Vulpia. Contrary to prediction, there is greater fungal colonization in the presence of Vulpia than in its absence. Additionally (and unexpectedly), it was found that dark septate endophyte (DSE) is present in the roots of A. californica, with colonization rates comparable to AMF colonization rates. Based on these results there is no indication that allelopathic chemicals from Vulpia decrease fungal colonization of A. californica.