Isi Makalah Widi

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1.1 Problem BackgroundLichens is the combination of fungi and algae that is morphologically and physiology is a unity. In their live, lichens do not need the high live requirements and hold out toward the lacking of water for a long time. Lichens products more than 500 uniques biochemical compound to adaptate in extrim habitat. Those compounds is used to control the sun light, Senyawa tersebut berguna untuk mengontrol sinar terik matahari, drive out, or repellen the herbivores, kill the microba and decrease the competition with animals, and others. Inspite of lichens grow well in nature in the unpriofitable condition, the lichens is very sensitive to the air pollution and quickly loss in the bad air pollution area. A reason that caused this is occurred that lichens can absorb a fluid and precipitate minerals from rain water and air and they can not take it outside. Therefore, the concentration of lethalic compound as SO2 is enter easily.

1.2 Problem Identificationsa. Lichens need the high of live requsite. b. Lichens hold out toward the lacking of water for a long time. c. Lichens produce more than 500 biochemical compounds. d. Lichens can adapt in extrim habitat. e. Lichens is very sensitive to the air pollution. f. Lichens can quickly loss in bad air condition. g. Lichens can absorb and precipitate the minerals from rainwater and air. h. The lethalic compound as SO2 can enter to the lichens body easily so that candeadly the body itself. i. Lichens can not take out the minerals from their own body.


1.3 Problem Formulationa. How to know the air pollution effects by observe the lichense colony. b. How to know the polluted and unpolluted area based on the lichens that are observed in the several locations of observation. c. The students do not understand yet about the varieties of lichens species that can be used to indicate the air pollution.

1.4 Objectives of Observationa. Students can know the effects of air pollution by observing the lichense colony and dust particles. b. Students can know the polluted and unpolluted area by observing the lichens colony and compute the colony of lichense. c. Students can know the level of pollution in several areas that are observed by compute the dust particles. d. Students can explain why the lichens can be used as bioindicators of air pollution. e. f. Students can understand the lichense specieses in the location of observation. Students can explain why the dust particles can be used as bioindicators of air pollution `

1.5 Benefit of ObservationAfter doing the observation of lichense and dust as bioindicator of air pollution, the students are expected to: a. Understanding the varieties of lichens in the location of observation. b. Understanding how the lichens reaction to respon the condition of their environment. c. Understanding where the polluted area and unpolluted area by observe the lichens in the location object of observation. d. Understanding the impact of air pollution by observe lichense in the location of observation.




2.1 Lichen StructureLichens are not plants. They are "composite organisms" made up of two, or maybe three, completely different kinds of organisms. It's as if you combined an animal such as a dog with a plant such as an oak, maybe with a fungus thrown in as well, and ended up with something very different from animal, plant or fungus. Something that was its own thing, with its own identity and manner of being. Every lichen species is part fungus. Usually the other species is a

photosynthesizing alga, but sometimes it can be a photosynthesizing bacterium known as a cyanobacterium. Sometimes all three kinds of organisms are found in one lichen. The above drawing gives an idea of what fungal hyphae wrapping around alga cells might look like at the microscopic level. In this amazing association the fungus benefits from the algae because fungi, having no chlorophyll, can't photosynthesize their own food. A lichen's fungal part is thus "fed" by its photosynthesizing algal part. The alga and/or cyanobacterium benefit from the association because the fungus is better able to find, soak up, and retain water and nutrients than they. Also, the fungus provides the resulting lichen shape, and the reproductive structures. This kind of relationship between two or more organisms, where all organisms benefit, is known as mutualism. The main body of a lichen is called a thallus. At the left you see the British Soldier Lichen, Cladonia cristatella. It's only about -inch high (6 mm). In this common lichen the red spore-producing reproductive structures are clearly visible. The lichen's name,Cladonia cristatella, is actually the name of the fungus. The alga species in the lichen is known as Trebouxia erici. However, it's


customary to name a lichen after its fungal part, so the whole lichen is known asCladonia cristatella. British Soldiers are usually found on decaying wood, soil, mossy logs, tree bases, and stumps. They help break down old wood and put nutrients back into the soil where they can be used by plants. Lichens also take nitrogen from the air and put it into the soil so plants can use it. The main structure on lichen is the body, called the thallus. Lichens are put into four groups according to the shape of the thallus.

Foliose lichens

flat, leaf-like structure

Fruticose lichens

bushy structure

Squamulose lichens

tiny, scale-like squamules

Crustose lichens

flat crust on or below rocks or under the bark of a tree


2.2 Lichen EcologyEcologically, lichens are important because they often occupy niches that, at least sometime during the season, are so dry, or hot, or sterile, that nothing else will grow there. For example, often the only plant growing on a bare rock will be a crustose lichen. That crustose lichen will be patiently collecting around and beneath itself tiny amounts of moisture, and mineral and organic fragments. When freezing temperatures come, the lichen's collected water will expand as it forms ice and maybe this expanding action will pry off a few more mineral particles from the rock below the lichen, thus making more soil. The water itself is a bit acidic, plus humic acids from the organic matter collected by the lichen will also be acidic, so these acids will likewise eat away at the stone. Over a period of perhaps many years, even centuries, the lichen gathers an extremely thin and fragile hint of a soil around it. As the lichen grows the soilproducing processes speeds up and takes place over an ever-larger area.. Eventually other more complex plants, perhaps a foliose or fruticose lichen, or mosses or ferns, or even some form of flowering plant, may take root in the modest soil and replace the crustose lichen. Thus crustose lichens on bare rock often begin a succession of communities, as described on one of our ecology pages. And when your heel dislodges a patch of lichen from a rock, you may be undoing the patient work of centuries... Certain lichens live on leaves, sometimes as parasites. These special leaf-living lichens are known as foliicolous lichens (not foliose). You might enjoy downloading a free, well-illustrated field guide to foliicolous lichens, in PDF format, presented by the Field Museum of Chicago.

2.3 Lichen ReproductionLichens reproduce in two main ways:5 | OBSERVATION OF LICHENS AS BIOINDICATOR OF AIR POLLUTION

The fungus part produces reproductive structures that further produce spores. If a spore lands and germinates, and the resulting hypha finds the right species of alga in the neighborhood, the hypha will grow through the algal cells and a new lichen will start developing.

By asexual (vegetative) techniques. One asexual strategy is that of fragmentation, which simply involves a piece of a lichen breaking off and this fragment then grows into a new lichen. Lichens also produce on their surfaces microscopic, dust-like particles composed of one or several algal cells closely enveloped by fungus hyphae. These are known assoredia. Each soredium can produce a new plant. Lichen fragments and soredia can be transported great distances by wind and water.

2.4 Lichen SymbiosisThe dual nature of lichen organisms was first proposed in 1869 by the Swiss botanist Simon Schwendener. Soon afterwards an imaginative Scottish priest described the dual relationship as the unnatural union between a captive algal damsel and a tyrant fungal master! This remark had a great effect on the Scottish psyche that has lasted to this day. See Scottish Lichenology. Lichens are the result of a physiological relationship between a fungus and a photosynthesising partner termed the photobiont. The photobiont is either green algae or bacteria that use blue-green pigment to photosynthesise; such bacteria are called cyanobacteria. The photobiont supplies food in the form of carbohydrate to the fungal partner; the fungal or mycobiont partner provides a home and some nutrients for the photobiont. Working together they take on the form and functionality of lichen. In the case of the photobiont being a green algae, when both are separated and grown separately, they form an amorphous mass unlike the original lichen form. This enforces the idea that the partnership is one of equality and not, as some writers have suggested, that the algae is prisoner to the fungus.


An interesting element of the symbiotic relationship is that in each lichen species the mycobiont is different, whereas the ph


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