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THE INDUCTION OF A LIGHT REQUIREMENT IN BIDENS PILOSA SEEDS BY LEAF CANOPY SHADE
Author(s) -
FENNER M.
Publication year - 1980
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1980.tb00752.x
Subject(s) - canopy , bidens pilosa , germination , darkness , biology , botany , horticulture
S ummary The aim of these experiments was to determine whether exposure to leaf‐canopy shade induces a light requirement for germination in Bidens pilosa seeds. Seeds of this species were pretreated by placing them in the shade of a natural canopy for 12 days and then setting half of them to germinate in full light and the other half in darkness. Canopy‐treated seeds acquired a marked light requirement. The pretreatment was more effective if the seeds were imbibed during it. Fresh and old seeds gave similar results. In a second experiment the effect of time of exposure to canopy shade on the induction of a light requirement was investigated. It was found that only 1 h exposure to leaf‐transmitted light is required to induce an almost complete light requirement in this species. The ecological implications of the results are discussed.