Botany Presentation On Lichens

BOTANY PAPER 1CHAPTER 3: LICHENSNAME : AFREEN BILAL SIDDIQUECLASS : FYBSC [CBZG]DIV : BROLL NO : 6936LICHENSINTRODUCTIONA lichen looks like a single organism, but it is actually asymbiotic relationshipbetween different organisms. It is composed of afungal partner(mycobiont) and one or morephotosynthetic partners(phycobiont). The photosynthetic partner is generally green algae or cyanobacteria. Their association represent mutualistic symbiosis where both the organisms are benefitted. There are about 13,500 species of lichen on the Earth.The fungi benefit from the carbohydrates produced by the algae or cyanobacteria viaphotosynthesis.The algae or cyanobacteria benefit by being protected from the environment by the filaments of the fungi, which also gather moisture and nutrients from the environment, and (usually) provide an anchor to it.Although some photosynthetic partners a lichen can survive outside the lichen, the lichen symbiotic association extends the ecological range of both partners, whereby most descriptions of lichen associations describe them as symbiotic.Hence they are known as Composite Plants.Both partners gain water and mineral nutrients mainly from the atmosphere, through rain and dust. The fungal partner protects the alga by retaining water, serving as a larger capture area for mineral nutrients and, in some cases, provides minerals obtained from thesubstrate.Evidence that lichens are examples of successfulsymbiosis