Fern Development Images
The objective is to provide imaging of the developmental stages of fern development from the spore to the young sporophyte.
The plates were inoculated on Monday 25 August 2014 and placed in the Sanyo incubator set to 27.5 degrees Celsius with 80% illumination (a photon flux of about 65 micromoles per square meter per second of photosynthetically active radiation).
Day 4
After four days at 28 degrees Celsius, some of the spores are just beginning to germinate. First to emerge are rhizoids, which
anchor the spores in the substrate.
Day 7
After seven days at 28 degrees Celsius, most of the spores have germinated. The photosynthesizing 'leaf' is just emerging from some of the
spores.
Day 9
After nine days at 28 degrees Celsius, the gametophytes continue to develop. At this stage, it is possible to distinguish
between male gametophytes (with a tongue or strap-shaped photosynthetic thallus) and hermaphrodite gametophytes (with a broad photosynthetic thallus).
Day 10
After ten days at 28 degrees Celsius, the sex of the gametophytes becomes clearer. They are not yet mature, but should be in a few days
Day 11
After eleven days at 28 degrees Celsius, the gametophytes are nearing maturity. The hermaphrodite gametophytes (now mitten-shaped) are
beginning to develop the archegonium near the notch.
Day 14
After fourteen days at 28 degrees Celsius, the gametophytes have reached maturity, and are fully primed for fertilization.
After adding distilled water, the spermatozoids are released and swarm near the archegonium of the hermaphrodite. The images were taken about
20 seconds apart, spermatozoid locations are marked in the lower panels.
A high magnification movie [1.2 MB .mov format] of the swimming behaviour of the spermatozoids can be viewed by clicking on the photo below.
Day 17
Just a few days after fertilization, the new fern baby is visible as a bump at the notch of
the hermaphrodite.
Day 21
After twenty-one days, the new fern sporophytes are developing their first leaf. Note that the hermaphrodites are becoming
pale as they provide nutrition to the new fern sporophytes.
Day 25
After twenty-five days, the more mature fern babies are developing a root.
Day 28
After twenty-eight days, secondary leaves are starting to emerge. On older sporophytes, the developmental stages of the leaves --from initiation to expansion-- are apparent.
The young sporophytes are ready for transplanting to soil (with gentle care to minimize damage to the new fern babies!)
Here is a photo of a culture plate [png].
Day 30
High magnification images at day thirty show details of the leaf initials and emerging leaves, including developing vascular strands.
Day 49
Now in the greenhouse (in one of the hot zones, 24-28 degrees Celsius), the sporophytes continue to grow.
Here are temperatures and relative humidities [png] in the Incubator (and inside the Plexi-Boxes) from Day 4 to Day 7
![photo of a culture plate [png]](Day_28_culture_plate.png){kind=link}
![temperatures and relative humidities [png]](Sanyo_Incubator.png){kind=link}