Nitrogen use strategies of neotropical rainforest trees in threatened Atlantic Forest |
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| Authors: | M P M AIDAR S SCHMIDT G MOSS G R STEWART & C A JOLY |
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| Institution: | Department of Plant Physiology and Biochemistry –Institute of Botany, São Paulo, Brazil,; Department of Botany, The University of Queensland, Brisbane, Australia,; Faculty of Science, The University of Western Australia, Nedlands, Australia and; Department of Botany –State University of Campinas, Brazil |
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| Abstract: | The characteristics of nitrogen acquisition, transport and assimilation were investigated in species of an Atlantic Forest succession over calcareous soil in south‐eastern Brazil. Differences in behaviour were observed within the regeneration guilds. Pioneer species showed high leaf nitrogen contents, a high capacity to respond to increased soil nitrogen availability, a high capacity for leaf nitrate assimilation and were characterized by the transport of nitrate + asparagine. At the other end of the succession, late secondary species had low leaf nitrogen contents, little capacity to respond to increased soil nitrogen availability, low leaf nitrate assimilation and were active in the transport of asparagine + arginine. The characteristics of nitrogen nutrition in some early secondary species showed similarities to those of pioneer species whereas others more closely resembled late secondary species. Average leaf δ15N values increased along the successional gradient. The results indicate that the nitrogen metabolism characteristics of species may be an additional ecophysiological tool in classifying tropical forest tree species into ecological guilds, and may have implications for regeneration programmes in degraded areas. |
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| Keywords: | δ 15N nitrate reductase activity nitrogen acquisition nitrogen metabolism regeneration strategy guilds secondary succession xylem sap nitrogen composition |
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