Bryophytes represent the oldest plants inhabiting the land, with some scientists putting its age to approximately 400 million years. Although a single plant is very small when viewed in isolation, their presence in forests is very conspicuous with some forests having a large mat cushioning trees trunks, rocks, and walls in the woodlands. Bryophytes comprise of three major taxonomic groups which are Bryophyta, Marchantiophyta, Anthocerotophyta. For this lab report, three species of Mosses, which is in the Bryophyta group and two species of Lichens will be used.
The behavior of mosses in relation to absorption of water and the antiseptic capability explains the reason behind its selection in the making of bandages, and diapers. This in itself point to an attribute related to its structure and morphology. In their very nature, mosses are soft and absorbent making them a perfect selection for use as padding, packing, and bedding materials. In their habitats, these plants play a vital ecological role by creating a firm foothold for other plants and acting as sponges for maintaining the required humidity in forest area during the dry spell (Tuba, Nancy, and Lloyd 12). A classical example of bryophyte group specie is Sphagnum, which has a remarkable ability to retain water.
The morphology of different species of lichens and mosses greatly influences their capability to absorb water and thus make these organisms to be suitably adapted to their habitats.
The objective of this laboratory experiment was to examine the water absorbency and retention qualities of selected species of mosses and some lichen that would be commonly found inhabiting forest floor. From the experiment, answers relating to why some species have better water absorbency and retention than others and why they do well in their habitats will be answered.
- 0.5 grams of each dry moss and lichen were weighed and recorded. This step was carried out carefully to ensure no soil was included in the sample nor a mixture of species were incorporated in one sample
- 10-20mL of water were added to each sample and allowed to soak for five minutes or until when the entire gametophytes and thallus were entirely saturated in water.
- The excess water was poured back into a graduated cylinder
- Through subtraction, the amount of water absorbed by each sample were determined and recorded as mL per gram of tissue
Figure 1 Images of he selected species of lichens and mosses used in the experiment
The amount of water absorbed by each specimen was obtained by computing the difference between retrieved water and the initially added volume. In order to obtain a comparative figure, the rate of retention was obtained according to the formula below:
Absorbency or Retention, mL/g =Volume of Absorbed water, mLWeight, g
The results depicted in the table and graph above shows that Spaghnum specie of mosses has the most capability to absorb water because its absorbency rate is at 19mL/g whereas those of other specimens are less than 10mL/g. From the other species, Peltigera leucophlebia specie of lichen had the second rate of absorbency followed by Moss 1, Cladonia Stellaris, Moss 4 and Moss 3 in that order.
The results obtained in the results shown above show that different species of lichens and mosses have varying capabilities in relation their ability to absorb water. This finding is attributed to the distinct morphology of respective species, which influence their capability to absorb water.
On the other hand, the gelatinous lichens have cyanobacterium, which exude a vital polysaccharide to take in water and retain, a role that is associated to the fungus. The sheet like structure found in foliose lichens is attached to the holding surface by a rhizines, which resemble roots. The thallus of selected lichens is highly differentiated, whereby its lower side is an absorptive tissue for an optimal photosynthesis function (Valladares, Leopoldo, and Carmen 104).
The extended capacity of thallus to hold water in the range of approximately six and eight mimiliters per grams depicted in the experiment is not because of the high water storage capacity, but it is attributed to e morphological and anatomical traits which enhance water-holding capacity and extend the time for photosynthetic activity. In this regard, the upper medulla and cortex in the thalli should play the vital role in delaying the water loss. This preposition is supported by the disparity in the capability of the two lichens used in the experiment. There is an extended ability of small thallus fragments in large species to maintain hydration (Nash 45).
In conclusion, the experiment has succeeded in determining the disparity in water holding capabilities of the investigated specimens of lichens and mosses. Their ability to hold water has always informed their selection for use in diapers, bandages, and management of oil spills. The experiment, through its results reaffirmed this position and further explained why other species are better than others. Notably, the differences in water holding capabilities of as depicted in the various species of lichens and mosses investigated are attributed to their morphological and anatomical attributes. These features inherent in water cells in the leaves and stems for mosses and thallus fragments for lichens create the necessary pockets for moisture retention.
Nash, Thomas H., ed. Lichen biology. Cambridge University Press, 1996. Print.
Robinson, Anne L., Dale H. Vitt, and Kevin P. Timoney. “Patterns of community structure and
morphology of Bryophytes and lichens relative to edaphic gradients in the subartic forest- tundra of Northwestern Canada.” The Bryologist 92.4 (1989): 495-512. Print.
Tuba, Zoltán, Nancy G. Slack, and Lloyd R. Stark, eds. Bryophyte ecology and climate change.
Cambridge University Press, 2011. Print.
Valladares, Fernando, Leopoldo G. Sancho, and Carmen Ascaso. “Water storage in the lichen
family Umbilicariaceae.” (1998). Print.