Details

Autor(en) / Beteiligte

• Inoue, Tomomi
• Nohara, Seiichi
• Takagi, Hiroyuki
• Anzai, Yasuharu

Titel

Contrast of nitrogen contents around roots of mangrove plants

Ist Teil von

• Plant and soil, 2011-02, Vol.339 (1-2), p.471-483

Ort / Verlag

Dordrecht: Dordrecht : Springer Netherlands

Erscheinungsjahr

2011

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Nitrogen is one of the most limiting elements for plant growth. Although nitrogen dynamics in mangrove forests are well understood at the ecosystem level, the nitrogen conditions in the root-zones of plants are less clear. The aim of this study was to analyze in detail the nitrogen conditions in the root zone of mangroves. We conducted a field survey in an area inhabited by three species of mangroves (Avicennia marina (Forsk.) Vierh., Rhizophora stylosa Griff. and Bruguiera gymnorrhiza (L.) Lam.). We collected soil and soil pore-water from the mangrove root zone, in which there were abundant fine roots, and from an area 10-cm away from the root zone (no-root zone). We determined soil organic nitrogen contents and concentrations of ammonium-N, nitrite-N and nitrate-N in soil pore-water along with soil temperature, NaCl and pH. We observed several common characteristics among the three mangrove species; in the root zone, pH was lower, soil organic matter content was higher, soil C:N was lower, and soil pore-water nitrite-N and nitrate-N were higher than their respective values in the no-root zone. These trends were observed in both summer and winter while soil temperature was about 10°C higher in summer than in winter. The fact that C:N was lower in the root zone than in the no-root zone suggests that bacterial nitrogen assimilation occurred near plant roots. The contrast in nitrogen content within a small scale (10 cm) between the root zone and no-root zone suggests that mangroves retain nitrogen source in their root zone. This property clearly works efficiently in intertidal habitats where tidal nitrogen export occurs naturally.