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AXIAL ROTATION OF ERYTHRINA HERBACEA LEAFLETS
Author(s) -
Herbert Thomas J.
Publication year - 1984
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1984.tb12487.x
Subject(s) - leaflet (botany) , erythrina , noon , morning , biology , rotation (mathematics) , interception , botany , elevation angle , elevation (ballistics) , horticulture , geometry , mathematics , atmospheric sciences , physics , ecology , azimuth
The leaflets of Erythrina herbacea, a leguminous plant native to subtropical North America, undergo daily movements. During the night, leaflets are oriented with their tips pointing downwards and show no rotation around the midrib of each leaflet. In the morning, leaflets rise, passing through a horizontal orientation and, somewhat before noon, reach a maximum average midrib elevation of approximately sixty degrees above the horizontal plane. Simultaneously, each leaflet rotates about the midrib by an average angle of forty to fifty degrees. These leaflet movements result in an initial increase in the relative leaflet surface area presented to the sun during the morning, a decrease in interception of direct solar radiation around noon, followed by a second maximum in light interception in early afternoon.