Arbuscular mycorrhiza infection enhances the growth response of Lolium perenne to elevated atmospheric pCO2

• Published in: Journal of experimental botany Vol. 53; no. 371; pp. 1207 - 1213
• Main Authors: Hartwig, U.A., Wittmann, P., Braun, R., Hartwig‐Räz, B., Jansa, J., Mozafar, A., Lüscher, A., Leuchtmann, A., Frossard, E., Nösberger, J.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.05.2002; OXFORD UNIVERSITY PRESS
• Subjects: Animal, plant and microbial ecology; Applied ecology; Atmospherics; Biological and medical sciences; Crop harvesting; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Elevated carbon dioxide; Fertilization; Fundamental and applied biological sciences. Psychology; Grassland soils; Leaf area; Microbial colonization; mycorrhiza; Non agrochemicals pollutants; Parasitism and symbiosis; Phytopathology. Animal pests. Plant and forest protection; Plant growth; Plant nutrition; Plant physiology and development; Plant roots; Plants; Plants and the Environment; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; ryegrass; Symbiosis; Symbiosis; Grassland; Nitrogen fertilization; Monocotyledones; Symbionte; Root; Phycomycetes; Carbon dioxide; Biomass; Fungi; Medium enrichment; Endomycorrhiza; Gramineae; Angiospermae; Mycorrhiza; Spermatophyta; Fodder crop; Lolium perenne; Climate modification; Thallophyta
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jexbot/53.371.1207

Elevated atmospheric pCO2 increases the C‐availability for plants and thus leads to a comparable increase in plant biomass production and nutrient demand. Arbuscular mycorrhizal fungi (AMF) are considered to play an important role in the nutrient uptake of plants as well as to be a significant C‐sink. Therefore, an increased colonization of plant roots by AMF is expected under elevated atmospheric pCO2. To test these hypotheses, Lolium perenne L. plants were grown from seeds in a growth chamber in pots containing a silica sand/soil mixture for 9 weeks with and without inoculation with Glomus intraradices (Schenck and Smith). The growth response of plants at two different levels of N fertilization (1.5 or 4.5 mM) combined with ambient (35 Pa) and elevated atmospheric pCO2 (60 Pa) was compared. The inoculation with G. intraradices, the elevated atmospheric pCO2 and the high N fertilization treatment all led to an increased plant biomass production of 16%, 20% and 49%, respectively. AMF colonization and high N fertilization increased the plant growth response to elevated atmospheric pCO2; the plant growth response to high N fertilization was also increased by AMF colonization. The root/shoot ratio was reduced by high N fertilization or elevated atmospheric pCO2, but was not affected by AMF colonization. The unchanged specific leaf area indicated that if AMF colonization represented an increased C‐sink, this was fully covered by the plant. Elevated atmospheric pCO2 strongly increased AMF colonization (60%) while the high N fertilization had a slightly negative effect. AMF colonization neither improved the N nor P nutrition status, but led to an improved total P uptake. The results underline the importance of AMF for the response of grassland ecosystems to elevated atmospheric pCO2.