whatis coralloid roots
Answers
Explanation:
The coralloid roots contain symbiotic cyanobacteria (blue-green algae), which fix nitrogen and, in association with root tissues, produce such beneficial amino acids as asparagine and citrulline.
Cycad seedlings initially form a stout, fleshy taproot that persists in subterranean forms for many years but is augmented by secondary roots which also are quite thick and fleshy. The taproots, larger secondary roots, and, in some cases, underground stems, have contractile elements in the pith and cortex that draw the stem more deeply into the ground.
Branch roots are of two kinds: long-branching geotropic roots and short-branching apogeotropic roots, which are referred to as coralloid because of their irregular, beady appearance. The coralloid roots contain symbiotic cyanobacteria (blue-green algae), which fix nitrogen and, in association with root tissues, produce such beneficial amino acids as asparagine and citrulline.
The taproot does not persist long in arborescent cycads but is replaced by large adventitious roots, which obscure the basic taproot system of the seedling. In all cycads, young roots are diarch with a parenchymatous cortex and an outer cover of epidermal scales. In this aspect they also resemble seed ferns. Older roots become triarch or tetrarch, eventually developing substantial amounts of wood and an outer covering of periderm.