Canopy-stored seed reserves (serotiny) in Cape Proteaceae

Many species in several genera of Cape Proteaceae retain seeds in serotinous cones for a number of years after they have matured. This study is a report on the contribution of canopy-stored seeds to viable seed reserves. Cone retention patterns were censused for most of the common serotinous species in southern Cape fynbos and for Protea nitida, a non-serotinous species. Germination trials were conducted in an open nursery to determine age-related variation in seed viability. Significant numbers of viable seeds were stored for a year or more in all the serotinous species studied but the contribution of two-year and older cones was small in Protea repens and Leucadendron conicum. These results suggest that seasonal variation in pre-burn seed reserves is not sufficient cause for recruitment failure in stands of serotinous Proteaceae burnt in winter or spring. Adaptive suites of characteristics associated with serotiny are described and contrasted with non-serotinous species of fynbos Proteaceae. Baie spesies van verskeie genusse van die Kaapse Proteaceae behou sade in serotienstrukture (keëls) vir ‘n aantal jare na volwassenheid. Hierdie Studie is ‘n verslag oor die bydrae van kroongestoorde sade tot lewenskragtige saadreserwes. Die patroon van keëldragingpatrone was gemonitor vir die meer algemene serotienspesies in die suidelike Kaapse fynbos en vir Protea nitida, ‘n nie-serotienspesie. Ontkiemingstoetse was onderneem in ‘n kwekery om verwantskap tussen ouderdom en die saad se lewenskragtigheid te bepaal. ‘n Betekenisvolle getal lewenskragtige sade is in die keels van al die bestudeerde serotienspesies gevind maar die bydrae van die twee jaar en ouer keëls was klein in die geval van Protea repens en Leucadendron conicum. Die resultate dui daarop dat die seisoenale variasie in die saadreserwes voor ‘n brand nie ‘n betekenisvolle oorsaak vir die mislukking in die herwinning van serotien-Proteaceae gedurende die winter of lente is nie. Aanpassings of kenmerke geassosieer met serotien word bespreek en gekontrasteer teenoor nie-serotienspesies van die fynbos-Proteaceae.

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