Sponsor
Fellowship and partial funding to J.A. Millar was provided by the Ronald E. McNair Scholars Program at PSU (DE grant P217A070199).
Published In
Journal of Applied Botany and Food Quality
Document Type
Article
Publication Date
11-2013
Subjects
Mycorrhizal fungi, Mycorrhizas in agriculture, Lima bean -- Growth, Lima bean -- Reproduction, Symbiosis
Abstract
Plants can respond with sink stimulation of photosynthesis when colonized with fungal or bacterial root symbionts, compensating costs of carbohydrate allocation to the microbes. However, constraints may arise under light limitation when plants cannot extensively increase photosynthesis. We hypothesize that under such conditions the costs for maintaining the symbiosis outweigh the benefits, ultimately turning the mutualist microbes into parasites, resulting in reduced plant growth and reproduction.
Using lima bean (Phaseolus lunatus) as experimental plant, we applied two levels of light (full light, 75% shading) and microbial inoculation (sterile soil, mycorrhizal fungi) and quantified both vegetative and generative plant traits.
As expected, shaded plants produced less vegetative biomass and seeds than non-shaded plants. However, individual seeds were significantly heavier in shaded plants and required less time for germination. While under both light conditions mycorrhizal plants showed a significantly reduced belowground biomass, mycorrhizal fungi neither enhanced overall plants performance in terms of total biomass and seed production nor resulted in measurable costs in either light condition. Our study suggest that mycorrhizal colonization neither provided benefits to lima bean plants grown under full light, nor created costs when photosynthesis was limited.
DOI
10.5073/JABFQ.2013.086.023
Persistent Identifier
https://archives.pdx.edu/ds/psu/33684
Citation Details
Ballhorn, Daniel J., Millar, Jess A. "Effect of Mycorrhizal Colonization and Light Limitation on Growth and Reproduction of Lima Bean (Phaseolus lunatus L.)," (2013) Journal of Applied Botany and Food Quality, volume 86. DOI: 10.5073/JABFQ.2013.086.023
Description
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Originally appeared in the Journal of Applied Botany and Food Quality, volume 86 (2013), published by Julius Kühn-Institut - Bundesforschungsinstitut für Kulturpflanzen (Federal Research Centre for Cultivated Plants).
A version of this work was subsequently published as a Portland State University Honors Thesis in 2014. It may be accessed at https://doi.org/10.15760/honors.38.