How do fern sporophytes meet their nutritional needs

The number of fronds and the length of the longest frond on sporophytes did Ching, a fern belonging to the Dryopteridaceae, grows in a variety of habitats Nutrients as well as other factors are implicated in the growth and . Usually, in cultures, fern spores need to be surface sterilized before the germination procedures. While they have veins that permit the flow of water and nutrients like conifers and To understand fern reproduction, it helps to know the parts of fern. The diploid sporophyte produces haploid spores by meiosis, the same. Evolutionarily, this addition of vascular tissue to plants is what allowed ferns to grow up diffusion for material movement and need to stay in close contact with the ground. To move food throughout the fern, glucose is pumped into the sieve elements The sporophyte plant is the one most commonly recognized as a fern.

After the second wash, the spores were diluted to a desired inoculation density usually by adding 10 ml of sterilized water of approx. As comparisons of gametophyte growth with and without sucrose in darkness or various light conditions showed no significant differences, this ingredient was not included in the media in any of the experiments for which data are presented see also Results and Discussion.

Terminology During development of the gametophyte the organism undergoes dramatic changes in morphology, and various terms are needed to distinguish newly differentiated cells and changing tissue infrastructure. The protonemata refers to the filamentous stage of gametophyte development. The initial, primary rhizoid emerges from the spore during germination.

Light and photoperiod treatments All light treatments in these studies were derived from adjustments to the timing or intensity of the cool white fluorescent source described above. The light source and fan were connected to a 24 h timer. For experiments in which gametophytes were exposed to lower intensities of light, individual Petri plates were wrapped in aluminium foil, and a rectangular window was created by removing a section of the foil covering the lid.

The films could be empirically adjusted to different OD optical density values by exposing them for various lengths of time to a red darkroom safelight. Since these transitions in form are complex and do not readily lend themselves to quantification by simple parameters such as numbers of cells or dimensions of structures, much of the Results section consists of photographic sequences that capture the progressive changes arising from cell divisions, cell expansion and cell differentiation.

Biological Diversity 5

Each of the photomontages, therefore, is the record of a single, representative gametophyte; in every instance I obtained complete photographic records of comparable development in at least six replicate organisms.

To counteract the desiccating environment of the laminar flow hood, an aluminium foil shield was taped behind the stage of the microscope and, with practice, one could transfer the gametophyte with some adherent agar, which, following transfer, was removed from the new agar surface. To improve visualization of gametophytes on an agar surface, a technique was developed for floating a small approx.

Small, pointed strips of Whatman number 1 paper were used to wick away some of the water between the chip and the gametophyte so that the chip did not drift away but at the same time did not press too closely to the organism. Considerable practice was needed to consistently achieve the desired apposition between the cellophane and the organism. These miniature coverslips were sufficiently porous to allow gas and nutrient exchange; unimpaired growth of gametopytes under these conditions was observed for periods exceeding 60 d.

Bromophenol blue is yellow at this pH. This entire preparation was then covered with a glass Petri dish lid and the edges sealed with water. The migration of the alkalinizing band could thus be measured over time; the rate of diffusion of ions D through cellophane appeared little different to that predicted for diffusion in unstirred water e. The plastic is hydrophobic and thus impermeable to ions and water. Given the hydrophobic nature of the underlying plastic film, this increment was sufficient to keep water from establishing continuity, and thus a path for ion diffusion between the chips.

The external surfaces of the gametophyte could, of course, serve as a path for diffusion, but this would be expected to be lower than the bulk flows in surrounding water, and, in any case, would not be artificially introduced, since such diffusion would be attributable to inherent features of the organism. Open in a separate window Fig.

Statistical differences were not observed in the germination of unsterilized spores immersed or not immersed in liquid nitrogen, but when the spores were previously sterilized, a severe inhibition of germination was observed in cryopreserved spores. Faster mean germination time was observed for unsterilized spores cryopreserved in liquid nitrogen for 15 minutes.

The germination of spores stored in liquid nitrogen for 90 days reached the maximum percentage after 12 days, while control spores reached their maximum percentage after 16 days. Levels of soluble sugars did not vary among treatments in gametophytes cultivated for 10 weeks after spore inoculation.

The number of fronds and the length of the longest frond on sporophytes did not differ statistically among treatments. The relative growth rate of sporophytes grown from cryopreserved and control spores were not statistically different among treatments.

Ching, a fern belonging to the Dryopteridaceae, grows in a variety of habitats from bare sandy soil, to areas with bushes, in forests, and even on rocks.

In fern cultures, sterilization of spores is necessary before germination procedures CamlohSimabukuro et al. The lowest mean germination time 7. The germination of R. Cryopreservation is a very useful technique for plants of economical interest as an important component in plant biotechnology programs Benson et al. This process involves a series of stresses that can disrupt physiology in the plant, promoting modifications in regenerating cultures. The verification of the genetic stability of the material recovered from cryopreservation after storage is desirable for germplasm conservation.

Cryopreservation can assist in the conservation of endangered species when used in germplasm banks. According to Pencefern spores are candidates for long-term germplasm storage at low temperatures including storage in liquid nitrogen.

Metabolism & Nutrition, part 1: Crash Course A&P #36

Spores of more than forty fern species survived after exposure to liquid nitrogen Agrawal et al. This paper investigates the effects of immersion of unsterilized and sterilized spores of Rumohra adiantiformis in liquid nitrogen on some growth characteristics. Materials and methods Sporophylls of Rumohra adiantiformis Forst. This method does not affect spore germination of R. Samples of sterilized and unsterilized spores stored under refrigeration, were separately placed in 1 mL sterile polypropylene cryotubes, plunged into liquid nitrogen LN cryocans and held for 15 min Rogge et al.

After cryogenic treatment, the samples were recovered from the LN and thawed out by two methods: Other samples were stored in LN for 90 days and after storage, they were rapidly or slowly thawed as described above. For the germination tests, spores were sown in four conical flasks containing 20 mL of Mohr's mineral solution as modified by Dyer MohrDyer and included Benomyl 50 mg L-1 to inhibit fungal growth.

Fern Reproduction

Ten sporophytes from each treatment were analyzed. The experiments were completely randomized. Germination was scored every two days. To normalize data, they were submitted to arcsine transformation. The mean germination time was calculated for each replication per treatment according to the equation: The number of fronds and the length of the longest frond were recorded after 23 and 39 weeks of cultivation in sporophytes produced from: The Kruskal-Wallis test or the Tukey test were applied to analyse number of fronds, height of longest frond and relative growth ratio.