Effects of metal lead on growth and mycorrhizae of an invasive plant species(Solidago canadensis L.)
YANG Ruyi , YU Guodong , TANG Jianjun , CHEN Xin
DOI:
Received August 16, 2007,Revised November 29, 2007, Accepted , Available online
Volume 20,2008,Pages 739-744
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It is less known whether and how soil metal lead (Pb) impacts the invasion of exotic plants. A greenhouse experiment was conducted
to estimate the e ects of lead on the growth and mycorrhizae of an invasive species (Solidago canadensis L.) in a microcosm system.
Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that allowed arbuscular
mycorrhizal (AM) fungal hyphae rather than plant roots to grow into the TEST compartments. Three Pb levels (control, 300, and 600
mg/kg soil) were used in this study to simulate ambient soil and two pollution sites where S. canadensis grows. Mycorrhizal inoculum
comprised five indigenous arbuscular mycorrhizal fungal species (Glomus mosseae, Glomus versiform, Glomus diaphanum, Glomus
geosporum, and Glomus etunicatum). The 15N isotope tracer was used to quantify the mycorrhizally mediated nitrogen acquisition of
plants. The results showed that S. canadensis was highly dependent on mycorrhizae. The Pb additions significantly decreased biomass
and arbuscular mycorrhizal colonization (root length colonized, RLC%) but did not a ect spore numbers, N (including total N and 15N)
and P uptake. The facilitating e ciency of mycorrhizae on nutrient acquisition was promoted by Pb treatments. The Pb was mostly
sequestered in belowground of plant (root and rhizome). The results suggest that the high e ciency of mycorrhizae on nutrient uptake
might give S. canadensis a great advantage over native species in Pb polluted soils.
