Etude des facteurs de contrôle de la floraison et de la fructification chez le sarrasin commun, Fagopyrum esculentum Moench (cv. La Harpe)
(2007)
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- Abstract
- Buckwheat (Fagopyrum esculentum Moench, Polygonaceae) is widely cultivated but the floral biology of this auto-incompatible distylous species was poorly studied. Compared with other cereals, it has a relatively low reproductive success. In the present study, its reproductive biology was investigated in growth rooms in order to study the reproductive structures (morphogenenesis, morph comparisons and nectar production) and their development under different light irradiances, photoperiods, resource supplying (by source and/or sink organ removals) and water stress. We also observed the behaviour of pollinators in the field and attempted to determine which events may affect its reproductive success. The activity of the reproductive meristems is potentially endless but abortion process stop the morphogenesis. Resource availability and photoperiod for a photensensible variety affect the meristematic activity and therefore the number of flowers. When the plant has one unfolded leaf, the morphogenesis of the reproductive structures occurs at many nodes and this stage was highly sensible to a water deficit. Diptera (Apis mellifera L.) and Hymenoptera (syrphid flies) were the principal visitors. A variation in the visitor guild occurred at the beginning and at the end of summer. Honeybee appeared to be an effective pollinator and the most numerous visitors. The nectar, hexoses-dominant , was secreted when the anthesis occurred by unicellular secretory hairs during all the light period even after fertilization. Its secretion was light dependent. Except for the morphology of the reproductive organs, both morphs differed only in the nectar production. Thrum flowers secreted more nectar than pin flowers and were preferentially visited by honeybee. No pollen limitation transfer was found but the seed set was very low because many flowers did not set a seed. Some flowers had an undersized gynoecium and were infertile but majority looked correctly formed. Within the inflorescence, the flower position had an influence on its fate. The percentage of seeds decreased whereas the percentage of normal flowers which did not set a seed increased from the base to the top. Last abortions appeared to be limited in comparison to losses caused by the early failure phenomena.
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Cawoy, V. (2007). Etude des facteurs de contrôle de la floraison et de la fructification chez le sarrasin commun, Fagopyrum esculentum Moench (cv. La Harpe). https://hdl.handle.net/2078.5/124109