Tag: botany

Mango and guava are propagated through grafting. It is a horticulture technique where the living detached portion of the plant is used to regenerate the growth. One plant is selected for its roots and this is called the stock or rootstock. The other plant is selected for its stems, leaves, flowers, or fruits and is called the scion. The joining of scion and stalk is known as inosculation. The techniques are mostly used in the asexual mode of reproduction. 

The increase in concentration of non-biodegradable substance with subsequent trophic level of a food chain is called bio-magnification.

Bentham and Hooker's system of classification is published in the book Genera Plantarum. It was published in 3 volumes from the year 1862 to 1883. It is a natural system of classification. In this book, they arranged the species according to the system. They grouped 97,205 species of flowering plants into 202 orders.

Lichen is a symbiotic association of fungi ( Ascomycota or basidiomycete) with an alga (Chlorophyceae or Cyanophyceae). The term Lichen was coined by Theophrastus (370-285 BC).

Lichens are a symbiotic partnership of fungus and algae. The dominant partner is the fungus, which gives the lichen the majority of its characteristics from its thallus shape to its fruiting bodies. So, thallus is foliose in lichens. Lichens occur in one of four basic growth forms. crustose, squamulose, foliose and fruticose. So, the correct answer is 'Lichens'.

The fungal part of the lichens is known as mycobiont. Cyanobacteria have a special structure known as heterocyst which is specialised to perform nitrogen fixation. It has specific enzymes like nitrogenase which actively fixes the atmospheric nitrogen to a usable form. They are autotrophic so they also fix carbon during the dark reaction of photosynthesis into organic compounds. This conversion process of inorganic carbon (carbon dioxide) to organic compounds is also known as carbon assimilation.

• The algal component carries out photosynthesis and produces carbohydrate glucose during the dark reaction of photosynthesis.
• Minerals are provided to the algal part by fungal mycelium. It absorbs water and minerals from the substratum.
• Lipids and proteins are neither supplied by algal part nor fungal part but synthesized within the organism itself.
• So the correct answer is 'Carbohydrate'.

Lichens are found in odd places which includes areas in the Arctic and Antarctic, and mountain tops. Lichens are found on soil, rock or tree bark. Some will also grow on old wood (dead branches, fence rails, etc.), masonry and cemetery headstones. Lichens are often found in extreme environments where other organisms are sparse.