Effects of elevated CO{sub 2} and N fertilization on ponderosa pine fine root turn-over
- and others
The rapid increase in atmospheric CO{sub 2} may alter patterns of C assimilation, allocation and sequestration; effects on roots being particularly important because they are a primary point of resource acquisition and uptake. The effects of elevated CO{sub 2} and nitrogen treatments on Pinus ponderosa fine roots and associated fungal structures were monitored for a two year period using a minirhizotron camera system The trees were grown in native soil in open-top field-exposure chambers at Placerville, CA and exposed to ambient air or ambient air plus either 175 or 350 {mu}mol mol{sup -1} CO{sub 2} and 3 levels of nitrogen addition (0, 100 and 200 kg ha{sup -1}). The majority (>90 %) of roots observed were smaller than 2 mm and the mean diameter decreased during the study. Root production was greatest in June and least in February. Root turnover was greater in summer than in winter, with very fine roots (<0.5 mm) disappearing most rapidly. Trees growing under elevated CO{sub 2} produced more roots in late summer as compared to trees under ambient CO{sub 2}. Roots receiving 0 and 200 kg N/ha survived longer than those receiving 100 kg N/ha. Roots produced under elevated CO{sub 2} live longer than those produced under ambient CO{sub 2}. The occurrence of mycorrhizae and fungal hyphae increased in response to CO{sub 2} treatment but not the nitrogen with the highest levels of occurrence were during the summer.
- OSTI ID:
- 95893
- Report Number(s):
- CONF-9507129-; ISSN 0012-9623; TRN: 95:004728-0161
- Journal Information:
- Bulletin of the Ecological Society of America, Vol. 76, Issue 2; Conference: 80. anniversary of the transdisciplinary nature of ecology, Snowbird, UT (United States), 30 Jul - 3 Aug 1995; Other Information: PBD: Jun 1995
- Country of Publication:
- United States
- Language:
- English
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