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Science 27 February 1987:
Vol. 235. no. 4792, pp. 1062 - 1064
DOI: 10.1126/science.235.4792.1062
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Articles

Apogeotropic Roots in an Amazon Rain Forest

ROBERT L. SANFORD JR. 1

1 Department of Biological Sciences, Stanford University, Stanford, CA 94305.

Roots of some tropical trees grow vertically upward on the stems of neighboring trees. Apogeotropic roots occur in 12 species across five families. These roots, originating as fine roots in the mineral soil, grow upward as fast as 5.6 centimeters in 72 hours. Apogeotropic root growth may be an adaptation to extremely low soil nutrient availability in Amazon forests. In these forests upward-growing roots obtain nutrients via the predictable pathway of precipitation that flows down along the stem. Apogeotropic roots form a nutrient cycling pathway in which nutrients are absorbed and transported directly from plant to plant, without entering the soil solution.

Submitted on September 25, 1986
Accepted on December 31, 1986


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ecological polarities of mid-Cenozoic fossil plants and animals from central Oregon.
(2004)
Paleobiology 30, 561-588
Evidence from Paleosols for the Geological Antiquity of Rain Forest.
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Science 265, 499-502
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Tropical rain forests.
J. Proctor (1989)
Progress in Physical Geography 13, 409-430
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