Zaadkieming en licht
Gorteria Dutch Botanical Archives , Volume 5 - Issue 7/10 p. 225- 227
The faculty of light-sensitive (photoblastic) seeds to survive in the soil in an imbibed state for many years and to germinate when exposed to light is ecologically important for many plant species, among them most annual weeds. Only a part of the seeds of these species will germinate after disturbance of the soil in which they are present. Of equal ecological importance is the induction of secondary dormancy in both photoblastic and non-photoblastic seeds by far red irradiation. In white light filtered through green leaves the ratio red/far red shifts considerably to the far red side. Consequently in a wood seeds of many species will be prevented from germinating, but when a clearing is made they soon germinate. As examples are mentioned the seeds of the tropical weed Ruellia tuberosa L. germinating in white light and in darkness, but not in far red or leaf-filtered light, and those of Digitalis purpurea L. germinating in white light only and which will in nature germinate abundantly soon after a wood has been cut.
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