Spore germination and gametophore development of mosses in response to competition

Interactions between moss species in their earliest growth stages have
received little attention. To what extent interspecific competition or
priority effects influence spore germination, protonemal development, and
gametophore emergence is unknown. We evaluated such effects in pairwise
interaction between six common bryophyte species: Atrichum undulatum,
Bryum argenteum, Ceratodon purpureus, Funaria hygrometrica, Hypnum
cupressiforme, and Leptobryum pyriforme. Interspecific
interactions were assessed in vitro. Spores were sterilized and sown on
agar plates in three treatments: 1) as single species cultures (controls),
2) as pairwise species cultures inoculated simultaneously, and 3) with a
time lag of 20 days between species. Data on time needed for spore
germination, germination rate, the time needed for gametophore
differentiation, number of gametophores per germinated spore and average
diameter of colonies were collected. We also performed spore germination
tests in single-species cultures at the start and end of the study, as
well as tests for density-dependency at spore germination and gametophore
formation.