Modification of Adventitious Roots – Class 11 | Chapter – 5 | Short Notes Series PDF
Modification of Adventitious Roots: Adventitious roots are modified for different purposes like storage of food, providing mechanical support, reproduction, etc.
Modification of Adventitious Roots
Storage Adventitious Roots
- Tuberous root: When food is stored in these roots, they become swollen and form a bunch. eg. Sweet potato (Ipomea batata)
- Fasciculated: Roots arise in bunch (cluster) from lower node of the stem and become fleshy eg. Dahlia, Asparagus.
- Nodulose: In this type, tips of roots swell up. eg. Melilotus, Curcuma amoda.
- Beaded or moniliform: When root swells up like a bead at different places after a regular interval. eg. Vitis, Momordica (Bitter gourd), Portulaca.
- Annulated: Roots having series of ring like swellings eg. Psychrotia
Stilt roots or brace roots
When root arises from lower nodes and enter in soil obliquely, known as stilt roots eg. Maize, Sugarcane, Pandanus (screwpine)
Prop root or pillar roots
When root arises from branches of plant and grows downward towards soil. It function as supporting stem for the plant. eg. Banyan.
Butteress root
Such roots appear from the basal part of stem and spread in different directions in the soil. eg. Ficus, Bombax , Terminalia. It is a characteristic feature of tropical rain forest.
Climbing roots
These roots arise from nodes and helps the plant in climbing. eg. Money plant (Pothos), Betel, Black pepper, Techoma.
Foliar roots or Epiphyllous roots
When roots arise from leaf they are called as foliar roots. eg. Bryophyllum, Bignonia.
Sucking or haustorial roots or Parasitic roots
In parasitic plant roots enter in the stem of host plant to absorbed nutrition from host. eg. Dendrophthoe, Cuscuta, Viscum.
Assimilatory roots
The aerial roots of Tinospora and submerged roots of Trapa (Water chestnut) become green and synthesize food. Podostemon also has green assimilatory roots.
Hygroscopic roots
These are found in epiphytes, specially in orchids and help in absorption of moisture from the atmosphere using special tissue called velamen. eg. Orchids, Banda
Contractile roots
They shrink 60 – 70% of the original length and bring underground organ at proper depth in the soil e.g., corm of Crocus (saffron), Fresia.
Root thorns
These are hard, thick and pointed thorns e.g. Pothos armatus.
- Reproductive roots: These are fleshy, adventitious roots used for vegetative reproduction e.g., sweet potato (Ipomea batata), Dahlia.
- Leaf roots: In Salvinia, one leaf of each node modifies into root like structure for balancing the plant in water.
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