AP BIOLOGY

Detailed explanation-1: -The coralloid roots are mainly present in the Cycas which constitute the symbiotic cyanobacteria. These organisms play a role in the fixation of nitrogen with the help of nitrogenase. The nitrogen fixation gives rise to beneficial amino acids such as asparagine and the citrulline for the growth of the plant.

Detailed explanation-2: -Complete answer: Cycas develop from the specialized organs which are called coralloid roots. Branching roots are of two kinds, one is branching geotropic roots and the other one is branching apogeotropic roots and these apogeotropic roots are referred to as coralloid roots.

Detailed explanation-3: -Cycas is a gymnosperm. The root exhibits two forms namely the taproot system for absorption of water and minerals. The coralloid roots that are dichotomously branched apogeotropic roots that are formed due to the formation of cyanobacterial colonies/infection in them.

Detailed explanation-4: -Coralloid root is developed in Cycas. It is produced in clusters at the base of the stem and protrudes out over the ground. It is dichotomously branched and greenish brown in colour.