Tag: botany

Foliose lichen is the most complex lichen. It is a lichen with leafy body parts or thallus and which generally have a cortex on each side of the leafy lichen body part thallus. Crustose lichens are lichens that grow like a crust of paint on their substrate, and especially sqamulose crustose lichens, may not be attached to the substrate at the edges, giving a leafy appearance similar to foliose lichens, but there is no lower cortex on the leafy part. Fruticose lichens are lichens that have a form similar to a tiny leafless, branching shrub that may have the branches flattened, so as to appear leafy, but foliose lichens have a single cortex wrapping around the branches, whereas foliose lichens generally have an upper and a lower cortex. Gelatinous lichens may appear leafy, but lack a cortex or internal structure, having the photobiotic component diffuse throughout the no fruiting part of the lichen body, whereas in foliose lichens the algae are in a layer. In foliose lichens, the layer of tissue containing the photosynthetic component has the algae more diffuse in the fungus than in foliose lichens, where the algal layer is generally very distinct.

In lichens, a relationship occurs in which the fungus lives as a dominant organism and algae like a slave, the relationship is known as helotism. It is a form of symbiosis in which one species is forced to perform tasks for another, for their mutual benefit. Thus, the correct answer is option B. 

Most lichen fungi belong to Ascomycetes. The lichen fungi cultivate partners, that manufacture food by photosynthesis. Sometimes, the partners are algae (kingdom Protista), other times cyanobacteria (kingdom Monera), formerly called as blue-green algae.

The photobiont supplies the association organic carbon from photosynthesis, and the mycobiont ensures protection and regulates the supply of minerals and water. The nutritional exchange between partners is probably much more complex than exchange of water and minerals for organic carbon.

Lichens and mosses are used as the indicators of air pollution. These structures grow on damp areas. Air pollutants which are in the gaseous forms get dissolved in the rainwater, especially SO$ _2$ can damage these plants, and check them from growing. In places where these vegetation are not growing, it indicates that the air is heavily polluted with sulphur dioxide and other pollutants. 

A lichen is a composite organism that arises from algae or cyanobacteria (or both) living among filaments of a fungus in a symbiotic relationship. The combined life form has properties that are very different from the properties of its component organisms. The fungus benefits from the symbiotic relation because algae or cyanobacteria produce food by photosynthesis. The algae or cyanobacteria benefit by being protected from the environment by the filaments of the fungus, which also gather moisture and nutrients from the environment, and (usually) provide an anchor to it. Thus, the correct answer is option C.

Certaria is a kind of lichen which lives in close association with green algae. It is a very good source of laxative which makes bowel movement easy and loosen the stools. Most of these species are found at high latitudes, occurring on sand and shrub lands.

Lichens are used as the indicators of air pollution. These structures grow on tree bark and rocks. Air pollutants which are in the gaseous forms get dissolved in the rainwater, especially SO$ _2$ (sulfur dioxide) can damage lichens, and check them from growing. In places where lichens are not growing, it indicates that the air is heavily polluted with sulfur dioxide and other pollutants. In cities, SO$ _2$ is one of the most common air pollutants as it releases from the vehicles.

Lichens are used as the indicators of air pollution. These structures grow on tree bark and rocks. Air pollutants which are in the gaseous forms get dissolved in the rainwater, especially SO$ _2$ (sulphur dioxide) can damage lichens, and check them from growing. In places where lichens do not grow, it indicates that the air is heavily polluted with sulphur dioxide and other pollutants. 

Foliose lichen is a lichen thallus growth form that has a 2-dimensional, flat, leaf-like lobes and lifts up from the surface. Parmelia is a medium to large foliose lichen with ends of the leaf-like lobes often squarish-tipped.