Sphagnum Moss
by: Sarah McGrath (SM)
Photograph of Sphagnum platyphyllum
Photograph of Sphagnum platyphyllum

Photograph of Sphagnum platyphyllum (8) (BB-V)

Classification and Diagnostic Characteristics


Kingdom: Plantae
Phyla: Bryophyte
Class: Sphagnopsida
Order: Sphagnales
Family: Sphagnaceae
Genus: Sphagnum
Species: Sphagnum platyphyllum
(4) (SJ)
All Plantae have chloroplasts, an organelle with a double membrane that houses enzymes and pigments that preform photosynthesis, allowing plants to make their own food. Chloroplasts came from primary endosymbiosis of cyanobacteria.
Green Plants are Plantae with Chlorophyll b, which creates the characteristically green color, and store their photosynthetic yields as starch within chloroplasts.

Strepotophytes are green plants that hold the egg in the parental organism.

Embryophytes, land plants, are strepotophytes that have branched apical (growing from the top) growth, plasmodesmata (plasma membrane-lined channels that are 20-40nm in diameter of cell walls that connect adjacent plant cells, allowing ions, water, small molecules hormones, RNA and protein molecules to travel), similarities of peroxisomes( an organelle where toxic peroxides are created and converted to water), mitosis , cytokinesis (the division of cytoplasm if a dividing cell), chloroplasts structure, protected embryo, cuticle (see integument section), multicellular sporophyte (see reproduction section), gametangia (see reproduction section), and thick walled spores.

Mosses are land plants with spores. Characteristics of mosses include a filamentous, long and thin, stage; sporophyte, the multicellular diploid plant called “spore plant”, grows apically (from the tip) from about 1- 10 cm. One particular moss like Dawsonia grows up to be about 50 cm. They don't have seeds, and they commonly grow close to each other in clumps in shady areas.(2)(Shwetha) There are about 1,500 different species.

http://mountainmoss.com/blog/wp-content/uploads/2010/10/GREEN-carpet-of-MOSS.jpg
http://mountainmoss.com/blog/wp-content/uploads/2010/10/GREEN-carpet-of-MOSS.jpg


Relationship to Humans


Humans use mosses in landscaping, because they are a hardy ground covering.

Humans use moss in many diverse and important ways. They are used for everything things from bandaging soldiers in the first world war, to the production of whiskey. Many whiskeys are made with grains that are steeped in water from a sphagnum bog, and due to its ability to absorb water and antiseptic qualities it serves as a better bandage then cotton. It is also used as a fossil fuel in parts of Europe. (3) (PS)

Sphagnum moss is most commonly used by gardners, who often mix dried sphagnum (peat moss) with soil in order to ensure that the soil will hold its highest water capacity. Particularly, the American white cedar grows in sphagnum which has been used to make shingles for houses due to the composition of its wood (7) (E.S.S.).

The two specific ways that sphagnum moss is used to condition soil and increase water and nutrient retention is though increasing capillary forces (capillary action) and cation exchange capacity. Capillary action is the ability for liquid to move without assistance from outside forces and against the strain of outside forces including gravity. This is achieved when liquid, in this case water, is in a situation where the the tubular space in which the water is in is small enough that the surface tension and the adhesive forces between the molecules of the water and of the soil lift the liquid. Sphagnum moss allows this to occur by forming tiny tubular spaces in the soil for the water to reside which allows for easier uptake of water and the nutrients included. Cation exchange capacity is the maximum amount of cations that the soil is able to hold at a given pH. The sphagnum moss is very good at exchanging nutrients mostly due to a specific molecule called unesterfied polyuronic acid. By exchanging many nutrients including calcium, magnesium, potassium, and sodium for hydrogen ions, it is able to maintain the pH at a healthy level for plants. (10) (BH)

Sphagmum has powerful antibacterial properties, because it contains a special antiseptic substance sfagnol. Even during the First World War, this moss was used as a dressing. Sphagnum-gauze pads and pencils sphagnum helped the wounded during the Great Patriotic War. Sphagnum grows slowly (up to 3 cm per year), while the lower part gradually dies and turns into peat. Such peat — fine fuel, it gives a lot of heat and forms a little ash. Its use and kakudobrenie, and as bedding for livestock. In a dry hummock in the old days kept the winter supplies of fruit and vegetables. And, of course, turf — the most important part of the land government mixtures for plants. (11) (MC)
Some very resourceful campers use sphagnum moss for diapering their children. It is very absorbent so it works very well for diapering children, and small dry particles of the moss act as a talcum powder for the child. (MDS) [1]

Habitat and Niche

Moss is a terrestrial, land living, plant. It grows in damp, cool places forming dense mats. Liquid water is essential in all stages of reproduction, and because moss does not have a vascular system, it must live in places where water can come to it. Moss is able to grow on soil, vascular plants, bare rock, dead trees, and even buildings. This ability is due to a mutualistic association with fungi, which helps absorb water and minerals.

In most habitats moss plays an important role in preventing erosion of soil, and in the process also preventing the washing away of vital nutrients for the environment. In the arctic and subarctic habitats, the mosses occupy the important niche of being a main source of nitrogen fixation, whereas legumes are a main source of nitrogen fixation in the more temperature regions of the world. (6) (WSS)
Moss will die if they grow in places that have low amounts of water and lots of sunlight. They will die if there is too much competition for the same necessities and too much of a basic pH of soil. Also putting chemicals on moss such as bleach will stop the growth of the moss or even just trying to rake the moss will prevent it from growing further. (9)(NC)

Moss growing on a rock. (LC)
Moss growing on a rock. (LC)


Predator Avoidance

Moss is green which helps it blend into its environment.

Sphagnum moss grows mostly in peat bogs. These bogs are extremely difficult to traverse and very few large herbivores are able to live in the actual bog. The moss is interwoven into layers of living and dead plant matter in a thick aquatic layer. Getting to the actual moss is very difficult for animals and not many animals choose the bog as their habitat. Many reptiles like turtles and amphibians can be fed sphagnum moss but are not normally capable of getting to it, Making to predator avoidance mechanisms ultimately unnecessary. (12) (DA)


Nutrient Acquisition

Nonvascular plants are small enough that minerals can be distributed by diffusion into the cell bodies. The mutually beneficial association with fungi also helps with nutrient uptake from its location.

Mosses lack root and vascular systems, so they have a limited ability to uptake nutrients from the soil. They do, however, possess the ability to extract nitrogen from the soil and compete for this nutrient within a variety of different ecosystems. Their consumption and emission of nitrogen makes them agents in the nitrogen cycle. (4) (BB-V)

Photosynthesis, the processes which converts carbon dioxide and water into carbohydrates and oxygen gas, occurs within the chloroplast.
6 CO2 + 6 H2O --> C6H12O6 + 6 O2

Photosynthesis is an endergonic (more energy in products, requiring free energy to occur) reaction. It has two sets of reactions- the light reactions and carbon-fixation reactions.

Light reactions: convert light energy to chemical energy of ATP and NADPH, a reduced electron carrier. The light reactions contain two photosystems, photosystem II and photosystem I, which are connected by the electron transport system.

Carbon-fixation reactions: Use ATP and NADPH with CO2 to produce carbohydrates.Also called the Calvin cycle, the cycle is made of three processes: the fixation of CO2, reduction of 3PG to form glyceraldehyde 3-phosphate, and regeneration of the CO2 acceptor, RuBP


Reproduction and Life Cycle

external image moss_-_life_cycle.jpg(13) (JF)

Moss reproduces through a sporophyte. The sporophyte is diploid; it has two sets of chromosomes. The sporophyte is attached to and nutritionally dependent on the gametophyte, which is photosynthetic making it nutritionally independent. When the sporophyte enters meiosis, it will make haploid, unicellular spore in the sporangium. The sporangium releases the ungerminated spores. The spore will germinate into a multicellular haploid gametophyte. These gametes will become gametangia, specialized sex organs. Archegonium is the female sex organ which is multicellular, flask-shaped with a long neck and swollen base, that produces one egg. Antheridium is the male sex organ where sperm is mass produced. Both the male and female organs are in the same plant, allowing it to reproduce by itself. However moss can also be fertilized by neighboring individuals, allowing gentic diversity in a population.

Once the sperm is released by the antheridium, it must swim or be transferred by raindrops to the archegonium. Chemical signals form the egg and archegonium attracts the sperm. Within the archegonium, specific cells at the top of the neck must break down to allow the sperm to travel inside. The sperm will then fuse with the egg nucleus to form a diploid zygote. Mitotic divisions of the zygote then produce a diploid sporophyte embryo which matures and produces a sporangium and the next gametophyte generation.

The life cycle of a moss begins with a haploid spore that germinates to produce a protonema, a mass of thread-like filaments or thalloid. After this stage, the moss grows and becomes a protonemata, which looks like a thin green felt that can grow on damp soil, tree bark, rocks, concrete, or a stable surface. This transitory stage begins growth of the gametophore (gamete bearer) from the protonema that separates into leaves and stems. A clump of moss is formed once a single protonemata develops several gametophore shoots.[2] (JLau)



Growth and Development

Nonvascular plants do not have leaves, stems, and roots, although they have analogous structures to each. Water can move through the mats by capillary action, leaf like structures catch and hold water. They grow to be on average a few centimeters tall to allow water and minerals to reach all parts.

A germinated spore will form into a rhizoid. From the rhizoid a bud will form and grow into a gametophyte with both sex organs that will fertilize into an embryo and eventually sporophyte with a sporangium that releases ungerminated spores.


Integument

Integument is the protective surface covering. In nonvascular plants, layers of maternal tissue protect embryos from desiccation (drying out). Some mosses have a cuticle, waxy lipid coating that slows water loss, but it can be very thin and thus ineffective.


Movement

Moss is a plant and is stationary. However, during reproduction sperm travels through water to reach the archegonium and ungerminated spores are dispersed.


Sensing the Environment

Moss is able to sense environmental changes through stomata changes (see gas exchange) and photosynthesis (see nutrient acquisition).


Gas Exchange

Stomata are pores that regulate gas exchange and help control water loss. Stomata are paired with guard cells that are specialized epidermal cells which control the opening and closing of each stomata. When the stomata are open CO2 can diffuse into the plant, but water vapor will diffuse out of it. To minimalize water loss, plants will open their stomata when light intensity is enough to maintain a moderate rate of photosynthesis, which needs both CO2 and water present to occur. Generally stomata will be open during day and shut at night. Guard cells respond to changes in light and CO2 concentration through solute potential. K+ concentration in guard cells drive the changes as a proton pump activated by light transports H+ out of the guard cell, and the electrochemical gradient pulls K+ into the guard cells. The increase in K+ causes the cell to take in more water, and as turgor pressure stretches the cell, the stoma opens. Without light, the guard cell diffuses K+ passively out of the cell, and water follows out through osmosis. The guard cell shrinks and the stoma closes.


Waste Removal

Moss contains distinct cells that are extremely absorbent to water. These cells can carry 20 times their own wights. When the water level of the increases, the moss will swell. Trapped air will allow the moss to float up, if in an aquatic environment. This allows sunlight. For excretion purposes, uronic acid, contained in the cell wall, will assist the transfer of ion, excreting hydrogen ions. (AWC)[3]


Environmental Physiology

Temperature Regulation:
Mosses are prone to rapid changes in temperature. Mosses have an early sensing of mild temperature increments occurs at the plasma membrane of plant cells, which in turn produces a heat shock response. This heat shock response is a specific membrane regulated influx of calcium ions. (14)(BS)

Water Regulation:
Moss is the best known nonvascular land plant. However, nonvascular can be a misleading term for moss as many possess a hydroid. Hydroids are a certain type of cell within the gametophytes and sporophytes which dies and leaves a tiny tunnel where water can travel. Hydroids act like the tracheid, the water conducting cell of vascular plants, but do not have lignin or the cell wall structure. Stomata also play a role in water loss (see gas exchange)

Because Moss was one of the first plants to make its way out of the water, it still had to live close to the water so it could get enough water intake. If it didnt get enough water, it would not grow and die. (ES)


Internal Circulation

Because moss is a non-vascular plant, it lacks a circulatory system with xylem (water transport) and phloem (nutrient transport) as in vascular plants. This means that moss is limited in height, which is why it grows short but covers a wide area. (15) (DM)


Chemical Control

Plant hormones play a role in regulation, growth, and development.

Photoreceptors are pigments that are associated with proteins. Light turns on these photoreceptors which regulate development processes that involve light responses.


Resources

1. Principles of Life Textbook, Hillis.
2. http:// en. wikipedia.org/wiki/Moss
3. http://science.jrank.org/pages/4460/Moss-Importance-humans.html
4. http://fieldguide.mt.gov/detail_NBMUS6Z0X0.aspx
5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1618885/
6.http://bryophytes.science.oregonstate.edu/page3.htm
7. "Moss- Importance to Humans." Science Encyclopedia, 2012. Web. 13 Dec. 2012. <http://science.jrank.org/pages/4460/Moss-Importance-humans.html>.
8. http://upload.wikimedia.org/wikipedia/commons/8/89/Sphagnum_moss.jpg
9. http://en.wikipedia.org/wiki/Moss
10. http://www.moutere.com/stories/storyReader$54
11. http://www.agro-food.net/archives/40
12. http://www.doeni.gov.uk/niea/nh008.pdf
13. http://www.baileybio.com/plogger/?level=picture&id=605
14. http://www.ncbi.nlm.nih.gov/pubmed/19773386
15. http://www.cartage.org.lb/en/themes/Sciences/BotanicalSciences/ClassificationPlants/Cryptogamia/Bryophyta/Nonvascular/nonvascular.htm

Review Questions

1. How do stomata help to minimize water loss during photosynthesis in moss? (JLev)
2. Describe the difference between nonvascular and vascular plants. Why does this make mosses important in primary succession as pioneer plants? (FZ)
3.How do mosses reproduce differently from most plants? (KG)
4. Why would it be difficult for moss to acquire nutrients directly from the soil (as compared to many other plants)? Given this limited ability, how does moss acquire nutrients it cannot produce through photosynthesis? (AA)
5. What kind of relationship does the sphagnum moss typically have with the plants in a gardener's garden? (mutualism, commensalism, parasitic, etc) Explain. (AY)
6. How long can a Sphagnum Moss survive with deprivation of water?

(*Sidenote: I'm not sure why the font becomes larger as you scroll down the page. I've tried to fix it a few times, but it always ends up becoming larger even though I've changed it to all the same style, color, and size.)
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    http://articles.earthlingshandbook.org/2012/11/29/sphagnum-moss-diapers/
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    http://en.wikipedia.org/wiki/Moss
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    http://www.ehow.com/about_6640813_peat-moss-excrete-waste_.html