Carolina C-FERN Express Extended Culture User Manual

C-FERN Express

™

Extended Culture Instructions

C-FERN Express™is a new strain of C-FERN®that has been developed to
enhance student investigations through to the fertile sporophyte stage of
the life cycle. Derived from two Japanese varieties of Ceratopteris
thalictroides, C-FERN Express exhibits very rapid gametophyte and
sporophyte development. It can be substituted for the wild-type strain
(RNWT1) in student investigations of the fern life cycle. Culture
requirements for gametophytes are essentially the same as with the
standard C-FERN strains. Slight developmental differences in
gametophytes are noted below. In addition, the following guidelines for
sporophyte culture will allow studies of the entire life cycle, from spore to
spore, within 60 days.

10-day gametophyte culture.

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Gametophyte Culture

Follow the basic procedure described in the culture instructions or online at
www.c-fern.org. If cultured at 82ºF, mature gametophytes can be observed at
10 days from sowing spores. While standard C-FERN gametophytes exhibit
clear distinctions between the small males and the larger hermaphrodites, the
distinguishing features may be a little less conspicuous with C-FERN Express
gametophytes. The basic distinction still exists between the males (smaller,
without meristem, and with many antheridia) and the hermaphrodites (larger,
with meristem, and
with both archegonia
and a few antheridia).
However, some
smaller C-FERN
Express gametophytes
with several
antheridia may look
like males initially but
then develop
a meristem
and become
hermaphrodites with
several archegonia.
Water added to
gametophyte cultures
at 10 days or later will allow fertilization by swimming sperm.
One week later, young sporophytes will be visible at the first leaf stage.

Sporophyte Culture

Sporophytes can be grown to maturity within the same size petri dishes
(60 mm) used for gametophyte culture. Dishes should be two-thirds full with
Basic C-FERN Medium. When sporophytes are from 1 to 2 weeks old, use a
sterile toothpick to transfer them to fresh dishes (four per dish). Maintain the
cultures in a Growth Pod or similar container under the same conditions as for
gametophytes. Be aware that cooler temperatures (as low as 75°F) may

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2

C-FERN Express

male (left) and

C-FERN 10-day-old

hermaphrodite

gametophyte

(right).

Note: These two images approximate actual size

differences between males and hermaphrodites.