Cycas- Normal vs Coralloid Root
Cycas is a Gymnosperm coming under the Class Cycadopsida and Order Cycadales. Cycas plants have TWO types of Roots – (1) Normal Roots and (2) Coralloid Roots. In this post, we discuss the Similarities and Differences between Normal Root and Coralloid Roots in Cycas with a Comparison Table.
Similarities between Normal Root and Coralloid Root
Ø Anatomically both the roots are differentiated into epidermis, cortex, endodermis, pericycle and stele.
Ø The stele in both the groups composed of radially arranged xylem and phloem.
Ø Pith is absent or small in both the groups
Difference between Normal Root and Coralloid Root
| Normal Root | Coralloid Root |
---|
Morphology |  |  |
Development | Develop from the radicle of embryo. | Develop from the normal roots |
Tap-root | From the tap-root system. | Do not form the tap-root. |
Geotropism | Positively geotropic and grow downward. | Negatively geotropic and grow upward. |
Branching | Comparatively less branched. | Coralloid roots are highly dichotomously branched. |
Appearance | Appear as normal roots of plants. | Appear as corals (due to severe branching). |
Root Hairs | Root hairs are present. | Root hairs are absent. |
Cortex | Cortex is small and uniform | Cortex is very large and differentiated into THREE zones – outer, middle and inner zones. |
Algal Zone | Algal zone is absent in the cortex. | A broad algal zone is present in the middle cortex. |
Symbiosis | NO symbiotic association with blue-green algae. | Blue-green algae present in the algal zone of cortex shows symbiotic association with the root. |
Vascular Tissue | Vascular tissue is diarch (two strands of xylem and phloem). | Vascular tissue is triarch (three strands of xylem and phloem). |
Secondary Thickening | Secondary thickening occurs. | Secondary thickening is usually absent. |
Function | The main function of the normal root is absorption and anchorage. | Function coralloid root is nitrogen fixation. |
Anatomy |  |  |
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@. Gymnosperms: General Characters
@. Gymnosperms: Classification
@. Cycas – Morphology, Anatomy, Reproduction & Life Cycle
@. Economic Importance of Gymnosperms