Waterlogging and fire impacts on nitrogen availability and utilization in a subtropical wet heathland (wallum)

Schmidt, S and Stewart, GR (1997) Waterlogging and fire impacts on nitrogen availability and utilization in a subtropical wet heathland (wallum). Plant Cell And Environment, 20 10: 1231-1241. doi:10.1046/j.1365-3040.1997.d01-20.x


Author Schmidt, S
Stewart, GR
Title Waterlogging and fire impacts on nitrogen availability and utilization in a subtropical wet heathland (wallum)
Journal name Plant Cell And Environment   Check publisher's open access policy
ISSN 0140-7791
Publication date 1997-01-01
Year available 1997
Sub-type Article (original research)
DOI 10.1046/j.1365-3040.1997.d01-20.x
Open Access Status
Volume 20
Issue 10
Start page 1231
End page 1241
Total pages 11
Place of publication MALDEN
Publisher WILEY-BLACKWELL
Language eng
Abstract Protein, amino acids and ammonium were the main forms of soluble soil nitrogen in the soil solution of a subtropical heathland (wallum). After fire, soil ammonium and nitrate increased 90- and 60-fold, respectively. Despite this increase in nitrate availability after fire, wallum species exhibited uniformly low nitrate reductase activities and low leaf and xylem nitrate, During waterlogging soil amino acids increased, particularly gamma-aminobutyric acid (GABA) which accounted for over 50% of amino nitrogen. Non-mycorrhizal wallum species were significantly (P < 0.05) N-15-enriched (0.3-4.3 parts per thousand) compared to species with mycorrhizal associations (ericoid-type, ecto-, va-mycorrhizal) which were strongly depleted in N-15 (-6.3 to -1.8 parts per thousand). Lignotubers and roots had delta(15)N signatures similar to that of the leaves of respective species. The exceptions were fine roots of ecto-, ecto/va-, and ericoid type mycorrhizal species which were enriched in N-15 (0.1-2 4 parts per thousand). The delta(15)N signatures of delta(15)N(total soil N) and delta(15)N(soil NH4+) were in the range 3.7-4.5 parts per thousand, whereas delta(15)N(soil NO3-) was significantly (P < 0.05) more enriched in N-15 (9.2-9.8 parts per thousand). It is proposed that there is discrimination against N-15 during transfer of nitrogen from fungal to plant partner. Roots of selected species incorporated nitrogen sources in the order of preference: ammonium > glycine > nitrate. The exception were proteoid roots of Hakea (Proteaceae) which incorporated equal amounts of glycine and ammonium.
Keyword Plant Sciences
Fire
Mycorrhiza
N-15 Natural Abundance
Nitrate Reductase Activity
Nitrogen Sources
Proteoid Roots
Root Specializations
Subtropical Heathland
Wallum
Waterlogging
N-15 Natural-abundance
Nitrate Utilization
Arctic Plants
Amino-acids
Mycorrhizal Associations
Organic Nitrogen
Soil
Ericaceae
Biology
Forest
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Biological Sciences Publications
Ecology Centre Publications
 
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Created: Tue, 14 Aug 2007, 03:01:39 EST