BIOTIC

BIOTIC Species Information for Chorda filum

Researched by

Nicola White

Data supplied by

MarLIN

Refereed by

Dr Stefan Kraan

Reproduction/Life History

Reproductive type

Alternation of generations

Developmental mechanism

Spores (sexual / asexual)

Reproductive Season

Sporophytes appear on shore Feb-March

Reproductive Location

As adult

Reproductive frequency

Annual protracted

Regeneration potential

Life span

Insufficient information

Age at reproductive maturity

<1 year

Generation time

<1 year

Fecundity

Millions of spores

Egg/propagule size

Fertilization type

Larvae/Juveniles
Larval/Juvenile dispersal potential	100-1000m	Larval settlement period	Not relevant
Duration of larval stage	Not relevant

Reproduction Preferences Additional Information

Chorda filum has a similar life-history to other Laminariales, exhibiting alternation of heteromorphic generations. The species has a macroscopic diploid sporophyte and a microscopic haploid gametophyte. The gametophytes consist of clumps of prostate, branched, filaments approximately 100 micrometres long. Female gametophytes are less branched than male ones and may be distinguished by their larger more densely pigmented cells. The male gametophytes are smaller, paler in colour and more densely branched than the females. Chorda filum exhibits a protracted reproductive period. Visible sporophytes appear on shores between February and mid-March and develop into secondary sporophytes between April and June. The sporophytes are washed away from October to February, leaving behind zoospores or gametophytes. The size of plants is not related to their state of maturity, although the smallest plants to bear sporangia have been observed to be 36.6 cm long. When the meristem becomes indistinct it is likely that fruiting has begun. During the period of fertility the whole plant except the lowermost 5-10 cm, is covered in unilocular sporangia. Experiments on growing Chorda filum in culture have shown that fruiting appears to be endogenously controlled and occurs irrespective of environmental conditions (South & Burrows, 1967).

Reproduction References

South & Burrows, 1967, Fredriksen et al., 1998,