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Open Access item Individual flowering time and maternal fecundity in a summer-flowering mediterranean shrub: making the right prediction for the wrong reason

Authors:Herrera, Carlos M.
Keywords:Flowering, Phenology, Lahiatae, maternal fecundity, Mediterranean plants, seed pro­ duction
Issue Date:1992
Publisher:Elsevier
Citation:Acta oecologica. 1992. 13 (1). 13-24.
Abstract:The study of the reproductive biology of those few Mediterranean perennials that flower during the summer drought period may provide an indirect test of the adaptive value of prevailing off-summer flowering in Mediterranean-climate plant communities. This paper presents a study of the correlates, in terms of female fecundity. of individual variation in flowering time in Lavandula Intl/li/ia Med. (Labiatac). a summer-flowering shrub, at a southeastern Spanish locality. The following questions are addressed: (I) Are individual dilkrences in tuning of flowering correlated with variation in total seed production on a per plant basis?: and (2) If they are. which of the maternal fecundity components determining total seed production arc phenology­ dependent? Total seed production of individual plants was significantly related to flowering time. early-flowering shrubs being more fecund than later-flowering ones. This was due to earlier- flowering plants producing fruits with a greater number of seeds, on average, than later-flowering ones. Results fully support the prediction, based on the assumption of increasing environmental severity as the dry season proceeds, that comparatively earlier-flowering individuals should gain some reproductive advantage over later-flowering conspecifics. Nevertheless, previous experimen­ ml studies on L. !atifolla have shown that number of seeds per fruit, the single fecundity component responsible for the influence of flowering phenology on seed production. is not altered by experimental increases in pollination intensity and water availability, thus negating the premises underlying the prediction. Alternative explanations for observed patterns are tentatively suggested.
[FR] L’étude de Ia biologic de Ia reproduction de quelques pérennes méditerranéennes qui fleuris­ sent ii Ia période séche de l’été peut apporter Ia preuve indirecte de Ia valeur adaptative d’une floraison qui. chez les peuplements végétaux méditerranéens. s’effectue majoritairensent hors période estivale. Cet article étudic les correlations, en termes de féconditC des femelles. de Ia variation individuelle du moment de Ia floraison chez Lazanclula Intl/li/ia Med. (Labiatae). arhuste a floraison estivale du sud-est dc l’Espagne. Les questions suivantes se posent: (I) les differences individuclles de Ia phénologie de Ia floraison sont-elles liCes ii Ia variation de Ia production totale de graines par plante’? et (2) si tel est Ic cas. quels eomposants de Ia féconditC maternelle determinant Ia production totale de graines sont phCnologie-dCpendants? La production dc graines par individu est signilicativemeni corrClCc au moment de Ia fioraison. iCs arbustes a floraison précoce étant plus fCcands que ccux a floraison tardive. En eflèt, les plantes zi floraison prCeoce produisent des fruits dont Ic nombre de graines est. en nioyenne. supCrieur ii celui des plantes tardives. Ces rCsultats corroborent totalement l’hypothCse scIon laquclle Ia rigucur de
URI:http://hdl.handle.net/10261/44697
Appears in Collections:(EBD) Artículos

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