Fenología de la gametogénesis, madurez de conceptáculos, fertilidad y embriogénesis en Durvillaea antarctica (Chamisso) Hariot (Phaeophyta, Durvillaeales)

Abstract

Fenología de la gametogénesis, madurez de conceptáculos, fertilidad y embriogénesis en Durvillaea antarctica (Chamisso) Hariot (Phaeophyta, Durvillaeales)Phenology of gametogenesis, maturity of conceptacles, fertility and embryogenesis in Durvillaea antarctica (Chamisso) Hariot (Phaeophyta, Durvillaeales)

No sex-related dispersal limitation in a dioecious, oceanic long-distance traveller: the bull kelp Durvillaea antarctica

“…In order to obtain information on coalesced holdfasts, in particular the maturity stage and sex distribution of travelling individuals, recently stranded rafts with holdfasts were collected on 33 beaches during winters 2013, 2014 and 2015 as the fertile phase of D. antarctica is primarily found between austral autumn and spring ( Santelices et al 1980, Collantes et al 2002 (Figure 1). A total of 1044 kelp rafts with holdfasts were evaluated for both their sex and their maturity stage (see below).…”

“…Each individual was then weighed on its own and measured from the base of the stipe to the tip of the blade. For this part of the study we only used individual holdfasts that had at least 250 g total weight (including holdfast, stipes and blades) and individual stipes that were at least 50 cm long, because at this size the individuals start to become sexually mature (Santelices et al 1980, Collantes et al 2002.…”

“…Using the large blade samples, thin transverse cuts were examined microscopically to determine both the sex and maturity stages of the conceptacles. As each stipe of a holdfast represents a single individual (González et al 2015), the maturity of 30 conceptacles per stipe were determined from different cuts following Collantes et al (2002) in order to describe the maturity stage of each stipe, which was done by identifying the most abundant conceptacle maturity stage. The current study aimed to determine whether the stipe was vegetative or reproductive, and thus we did not distinguish between the different maturity stages described by Collantes et al (2002).…”

“…As each stipe of a holdfast represents a single individual (González et al 2015), the maturity of 30 conceptacles per stipe were determined from different cuts following Collantes et al (2002) in order to describe the maturity stage of each stipe, which was done by identifying the most abundant conceptacle maturity stage. The current study aimed to determine whether the stipe was vegetative or reproductive, and thus we did not distinguish between the different maturity stages described by Collantes et al (2002). As the conceptacles described by Collantes et al (2002) as "immature" contain fully developed gametes and are very close (within hours or days) to becoming "fully mature", we considered these as reproductive.…”

“…The current study aimed to determine whether the stipe was vegetative or reproductive, and thus we did not distinguish between the different maturity stages described by Collantes et al (2002). As the conceptacles described by Collantes et al (2002) as "immature" contain fully developed gametes and are very close (within hours or days) to becoming "fully mature", we considered these as reproductive. Also, since senescent individuals as described by Collantes et al (2002) release very few gametes and the conceptacles are closed and moving to the medullar tissue (reverting to vegetative state), all senescent individuals were considered to be vegetative.…”