What kind of soil is needed to grow C-Fern sporophytes? Does soil pH need to be adjusted?
C-Fern sporophytes grow well in commercially available ProMix® potting mix. ProMix works very well for both greenhouse or terrarium culture (see mini-terrarium instructions) and has some starter fertilizer in it to get things going. Soil pH is not adjusted when using Promix potting material. Sporophytes grown in mini-terraria typically need no additional fertilization to grow […]
‘We got the C-Fern to grow in soil and for a month or so they were doing really well. Then, after returning from vacation, the ferns were wilted in their pots. What happened?’ Several factors may be responsible for the wilting of sporophytes Could they have not gotten watered over a weekend? Did environmental conditions […]
Sperm chemotaxis directions say to use 12-18 day old cultures. What exactly does this mean?
For sperm chemotaxis (e.g. Chemical Attraction – C-Fern Sperm Chemotaxis or simple observation) directions say to use 12-18 day old cultures. Does this mean I should sow the spores 12-18 days in advance, or does the 12-18 day age indicate the number of days after the gametophytes germinate? The timing refers to the age of […]
Swimming sperm are seen shortly after adding water to cultures but seem to disappear quickly.
If water is added to a C-Fern culture, sperm are typically released quickly – within a few minutes. Because there are many hermaphroditic gametophytes in the culture, sperm are immediately attracted to them and cluster tightly around the area of mature archegonia. Once attracted to the archegonial region, sperm do not appear to swim away […]
The easiest way for most users to cultures sporophytes is to use a Mini-terrarium constructed from a plastic drink bottle. Instructions for construction and use of the Mini-terrarium are available at Sporophyte Culture – Mini-terrarium. Bottles as small as 8-ounces or as large as 2-liters can be used. The commercially available potting soil (i.e. ProMix®) […]
Why do you sometimes get genetic ratios that are quite different from the expected?
“Unexpected” genetic ratios are typically associated with sampling error and an unconscious tendency to bias counts towards one of the phenotypes. Students should be carefully instructed in the proper ways of data collection, including a very thorough explanation of appropriate random sampling. One common problem is the tendency to ‘select’ individuals for counting rather than […]
C-Fern cultures are largely resistant to many fungal contaminants, although some fungi can be pathogenic. For routine observations, the presence of some contamination will not generally interfere with gametophyte growth or development. Contamination by certain types of algae can be much more destructive since contamination can spread rapidly and infect other cultures. If algal contamination […]
Certain types of fungal contaminants can cause excessively long rhizoid growth. In fact, this could be starting point for interesting research projects.
Magnification is typically not the problem since sperm can be adequately visualized even at a total magnification of only 25 X. Usually, difficulties observing sperm are often associated with improper or insufficient illumination. Bottom (transmitted) illumination is preferred. If adjustments are possible, try increasing or decreasing the intensity of the light source. Also, if a […]
We recommend using Difco-Bacto agar. This is a relatively purified and inexpensive brand that has consistently given excellent results. Other agars, for example, those recommended for plant tissue culture uses or more highly purified types, sometimes yield poor or unusual growth of gametophytes.