GENERAL KNOWLEDGE

Detailed explanation-1: -Besides paddy fields, cyanobacteria are also found inside vegetative part of Cycas. Cycas has coralloid roots which are irregular, negatively geotropic, dichotomously branched coral like roots. They do not possess root hairs and root caps. Cyanobacteria like Nostoc and Anabaena are present in coralloid roots.

Detailed explanation-2: -Some cyanobacteria (e.g., Anabaena, Nostoc) help in nitrogen fixation. They are abundantly found in paddy fields. Cycas is a gymnosperm that belongs to the Cycadaceae family. It contains a special type of root called ‘coralloid roots’.

Detailed explanation-3: -In the paddy fields, cyanobacteria, for example, blue green growth settle climatic nitrogen to improve the nitrogen substance of soil. In this manner, the whole need of nitrogen to rice product can be provided by blue green growth, prompting increment in yield.

Detailed explanation-4: -Answer: Cyanobacteria like Anabaena, Nostoc, Oscillatoria serve as an important biofertiliser in paddy fields as they fix atmospheric nitrogen and add organic matter to the soil and increase its fertility.