Please use this identifier to cite or link to this item:

Title: Opportunity for hybridization between two oak species in mixed stands as monitored by the timing and intensity of pollen production
Authors: Varela, Maria Carolina
Brás, Rita
Reforço Barros, Isabel
Oliveira, Paulo
Meierrose, Carola
Keywords: Hybridization
Cork oak
Holm oak
Phenology of flowering
Acorn production
Quercus suber
Quercus rotundifolia
Quercus ilex subsp. rotundifolia
Issue Date: 2008
Publisher: Elsevier B.V.
Abstract: The opportunity of cross-pollination in mixed stands of two oak species (cork oak and holm oak) was studied by characterizing individual phenologies of flowering. In the spring of 1998 at one stand consisting of 64 marked trees, there was a period of 19 days when maximal pollen release in one species and stigma receptivity in the other occurred simultaneously, enabling interspecific gene flow in either direction. This happened in spite of an average time separation of 22 days between the two species,reflecting a considerable intraspecific variation in the timings of flowering. Flowering intensities (as estimated from male flower abundance) were high, but fruiting intensities were comparatively low.Shortly after pollination, considerable abortion of female flowers and early fruits was recorded. In 2000,the interspecific overlap of phenologies was drastically reduced due to a delay in cork oak flowering. On the other hand, the individual timings were repeatable for most trees, at least in holm oak. Two other mixed stands were subject of parallel studies, with similar results in all traits except for a less dramatic reduction in fruiting intensities. In spite of the high opportunity for cross-pollination in 1998, and given the lack of hybrids among the progenies from the subsequent fruiting season [Oliveira, P., Custodio, A.C.,Branco, C., Reforço, I., Rodrigues, F., Varela, M.C., Meierrose, C., 2003. Hybrids between cork oak and holm oak: isoenzyme analysis. Forest Genet. 10, 283–298], it can be concluded that the prerequisite of crosspollination is clearly insufficient for hybridization to succeed. Post-pollination processes must play an important role in the maintenance of reproductive isolation between the two species.
ISSN: 0378-1127
Type: article
Appears in Collections:BIO - Publicações - Artigos em Revistas Internacionais Com Arbitragem Científica

Files in This Item:

File Description SizeFormat
Varela et al 2008.pdfArtigo367.64 kBAdobe PDFView/Open
FacebookTwitterDeliciousLinkedInDiggGoogle BookmarksMySpaceOrkut
Formato BibTex mendeley Endnote Logotipo do DeGóis 

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.


Dspace Dspace
DSpace Software, version 1.6.2 Copyright © 2002-2008 MIT and Hewlett-Packard - Feedback
UEvora B-On Curriculum DeGois