LICHEN by Annie Cloutier copyright 2012 BotanyHow can a plant be both a fungi and an algae ?
Symbiotic Relationships in lichen there are two components; fungi and algae• A photosynthetic component • A green algae or a> the algae cyanobacterium • 90% 0f lichen have an algae component • Each lichen species has its own unique species of fungi • Fungi protect the spongy• A decomposer component thallus from too much> the fungi sunlight • The photosynthetic component provides food for both organisms
Slow growth...very slow•The maximum rate of growth for a lichen is ~1 cm (centimeter) per year and as little as 0.1mm millimeter
Got drought ? How about a flood ? Lichen can survive both• Lichen can survive with only 2% water content of their dry weight• When this happens the thallus acts a a sun screen to keep the sunlight from drying out the remaining spongy medulla• The thallus is composed of gelatinous substances that allows the lichen the versatility to survive extreme variations in rain fall and temperatures
NOT a parasite•Lichen may be attached to trees but they are not a parasite.
Sex or no sex ?• Lichen reproduce primarily by asexual means….but• The fungal component reproduce sexually !• A third of the species, small powdery clusters of hyphae disperse soredia and algae bits of the lichen’s thallus, break off and get dispersed by rain or wind.• Epiphytes, hang from tree branches at great heights wind swept spores and animals moving through the areas of lichen transport the spores• Lichen algae reproduce by mitosis and simple cell division