Question

Coralloid roots of Cycas has
A. Anabaena
B. Azolla
C. Mycorrhizae
D. Rhizopus

Answer 1

Hint: The coralloid roots contain the symbiotic cyanobacteria that are blue-green algae, which fixes the nitrogen and, in association with root tissues. It also produces beneficial amino acids such as the asparagine and the citrulline.

Complete step by step answer: The cycas develop specialized organs called coralloid roots.
These roots help them form a mutualistic and symbiotic relationship with the cyanobacteria (Anabaena).
Also, these coralloid roots are produced in the clusters at the base of the stem which because of its apogeotropic growth protrudes out over the ground. It is dichotomously branched and with Anabaena allowing nitrogen fixation. The cycas are the only known gymnosperms that fix the nitrogen symbiotically through an intimate association with cyanobacteria. The cyanobacteria are located in special roots termed as coralloid roots, which consist of numerous dichotomously branched structures arising from the lateral roots.
Therefore, the correct answer is option A.

Additional information: The vesicular-arbuscular mycorrhizae are the most abundant of a group of the symbiotic fungi that infect plant roots. These tubes originally grow from the fungal spores, extending short distances into the soil in search of the roots of the host plants.

Note: The Anabaena is a genus of filamentous cyanobacteria that exist as plankton in nature. They are well known for nitrogen-fixing abilities, and they form the symbiotic relationships with certain plants, such as the mosquito fern.