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Roots ( Provides anchorage and stability ) (Other types of Roots and Root…
Roots ( Provides anchorage and stability )
External structure of roots
Organization of Root Systems
Tap root ( It is much larger and has numerous small lateral roots or branch roots coming out of it. It develops from embryonic root called the radicle.
For example, radish, tobacco seedling etc.
Fibrous root ( Also, known as adventitious root as roots do not arise on pre- existing roots)
For example, maize, wheat etc.
Structure of Individual Roots
This type of root is very simple, as it has no leaves or leaf scars, neither leaf axils nor axillary buds.
Internal structure of Roots
Root cap ( It provides effective protection for the root apical meristem)
Root Apical Meristem ( It produces regular flies of cells and extend into the regions of mature root tissues )
Zone of Elongation ( It is just behind the root apical meristem, Cells begins to differentiate into a visible pattern)
Zone of Maturation/ Root Hair Zone ( Root hairs grow outward, greatly increasing absorption of water and minerals).
Transport of minerals from the epidermis to the vascular tissues occurs by either apoplastic or symplastic transport.
Casparian strips are involved in controlling the types of minerals that enter the xylem water stream.
Origin and Development of Lateral roots
They are initiated by the cell division in the pericycle.
Other types of Roots and Root Modifications
Storage Roots ( Provides long term storage for carbohydrates. For example, beets, carrots, and celery etc.
Prop Roots ( They make contact with the soil and transport additional nutrients and water to the stem for example, Ficus)
Aerial Roots of Orchids ( These roots spread along the surface of the bark and often dangle freely in the air)
Contractile Roots ( It undergoes more contraction than Prop roots , for example, Oxalis, Gladiolus etc )
Mycorrhizae ( The association of symbiotic relationship between roots and soil fungi is Mycorrhizae).
There is two kinds of relationship
Ectomycorrhizal relationship ( fungal hyphae penetrate between the outermost root cortex cells but never invade the cells themselves ).
Endomycorrhizal association ( in which hyphae penetrate the root cortex as far as the endodermis, but cannot pass the casparian strip
Root Nodules and Nitrogen Fixation ( It is the chemical conversion of atmospheric nitrogen into usable compounds ).
Haustorial Roots ( Roots of parasitic plants )
Roots of Strangler Figs ( grow as epiphytes on a branch of a host tree ).
