A) Cycos
B) Pinus
C) Fern
D) Selaginella
Correct Answer: A
Solution :
Coralloid roots are present in Cycas. These are specialised apogeotropic roots, which grow on the surface of soil. They are repeatedly dichotomously branched and appear as coralline masses. They are most frequent on young plants. A specific algal zone with colonies of Anabaena or other blue-green algae is present in cortex of these roots. Coralloid roots possess lenticels, which help in respiration. Primary root is typical tap root in Pinus. It does not penetrate deep into the soil. The lateral roots grow exclusively and help the plant to keep firm in the soil. The root hairs are poorly developed and the roots are covered with fungal hyphae, called mycorrhiza. The fungi present in the ectotrophic mycorrhiza are mainly species of Amantea, Bolyutus, Clavaria and Scleroderma. They remain in symbiotic association with the roots. In Selaginella, primary roots are ephemeral and adult plants have adventitious roots. In majority of creeping species with dorsiventral stem, the roots arise at or close to the point of dichotomy. In species like S. rupestris and S. wallichii, they arise at the point of dichotomy as well as other position. Ferns are perennial and evergreen with an underground rhizomatous stem, large aerial leaves or fronds and adventitious roots.
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