Question

Which of the following physiological process happens in lichens when the phycobiont is a cyanobacteria?

• A. Nitrogen fixation
• B. Carbon fixation
• C. Carbon assimilation
• D. All of the above

Answer 1

Answer: (D)

All of the above

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.

So, the correct answer is 'Nitrogen fixation, Carbon fixation and Carbon assimilation'.