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Research article2003Peer reviewed

Spines as a mechanical defence: the effects of fertiliser treatment on juvenile Acacia tortilis plants

Gowda JH, Albrectsen BR, Ball JP, Sjoberg M, Palo RT

Abstract

Using growth of different tissues in Acacia tortilis as a model, we tested current hypotheses on how nutrients affect mechanical plant defence. In a greenhouse experiment we applied a balanced commercial fertiliser (NPK) at three treatment levels to juvenile potted Acacias. As expected, plants increased in size with nutrient addition. More importantly, however, the relative mass of long spines increased significantly more than other structural components (leaves and twigs). This effect is not predicted by current nutrient availability hypotheses; which suggest either equal or proportionally lower investment in mechanical defence with increasing nutrient availability. Our results suggest that investment in spine size is nutrient limited in Acacia tortilis. It is commonly observed that the risk of damage by herbivores is highest on plants growing in nutrient-rich soils. If spines act as an effective form of anti-herbivore protection, then these plants might be expected to increase their production of physical defences (long spines) under such circumstances. Plants growing under higher nutrient conditions might therefore invest more in constitutive defences. These changes in allocation pattern are consistent with the increase in production of long spines, which are also induced by browsing. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved

Published in

Acta Oecologica
2003, Volume: 24, number: 1, pages: 1-4
Publisher: GAUTHIER-VILLARS/EDITIONS ELSEVIER

      SLU Authors

    • Albrectsen, Benedicte

      • Department of Animal Ecology, Swedish University of Agricultural Sciences

      • Ball, John

        • Department of Animal Ecology, Swedish University of Agricultural Sciences

        • Sjöberg, mikael

          • Department of Animal Ecology, Swedish University of Agricultural Sciences

          • Palo, Thomas

            • Department of Animal Ecology, Swedish University of Agricultural Sciences

          UKÄ Subject classification

          Environmental Sciences related to Agriculture and Land-use

          Publication identifier

          DOI: https://doi.org/10.1016/S1146-609X(02)00002-4

          Permanent link to this page (URI)

          https://res.slu.se/id/publ/555