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Needle cytokinin content as a sensitive bioindicator of N pollution in Sitka spruce
Previous work has shown that conifers growing on sites exposed to aerial pollution exhibit a different pattern of vegetative development in comparison with those on unpolluted sites, and have higher needle cytokinin contents (von Schwartzenberg & Hahn, Journal of Plant Physiology 139, 218-223, 1...
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Published in: | Plant, cell and environment cell and environment, 2003-12, Vol.26 (12), p.1929-1939 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Previous work has shown that conifers growing on sites exposed to aerial pollution exhibit a different pattern of vegetative development in comparison with those on unpolluted sites, and have higher needle cytokinin contents (von Schwartzenberg & Hahn, Journal of Plant Physiology 139, 218-223, 1991). Physiologically mature Sitka spruce (Picea sitchensis[Bong.] Carr) trees growing in a commercial plantation were sprayed with combinations of S, N and acidity from bud burst until December, for a 3 year period, in order to factor out the effects of individual pollutants and identify the specific component responsible for the high cytokinin content. Cytokinins were monitored using high-performance liquid chromatography/enzyme-linked immunosorbent assay techniques. After 3 years of treatment only needles of neutral N-treated trees contained significantly higher levels of cytokinin than those of trees receiving no spray. The addition of acid S could suppress the effects of added N. Needles from neutral N treatments also contained significantly higher levels of biologically active cytokinins and forms that can be transported in the xylem/phloem. Significantly lower levels of active cytokinins were present in needles sprayed with N in combination with acid sulphate. The results demonstrate that the needle cytokinin content may be used as a sensitive and selective bioindicator of the early stages in N perturbation in coniferous trees. |
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ISSN: | 0140-7791 1365-3040 |
DOI: | 10.1046/j.1365-3040.2003.01109.x |