Modification of Plant Parts- An Overview


>2.Aerial Roots – are aerial nodes that develop from the stem and go into the soil. Example: stilt roots of sugarcane and maize, prop roots of banyan trees which provide reinforcement to the stout branches.

3.Parasitic Roots – arise from stem and penetrate into the host plant. They are called ‘Haustria’. Example: Cuscuta.

4.Respiratory Roots – have pores and are found in plants that thrive in swamps, e.g. Rhizophora.

5.Assimilatory Roots – contain chlorophyll and perform the function of carbon assimilation, e.g. Trapa roots.

6.Epiphytic roots – are aerial roots which absorb moisture from air, e.g. Vanda roots.

Stem Modifications – In some plants the stem is modified to perform different functions, viz.
(i)Rhizomes- underground modifications of the stem. They bear nodes and store food material, e.g. ginger, grass and canna.

(ii)Tuber- are swollen tips of underground branches that store food, e.g. potato.

(iii)Corm – underground stem which bears leaves, e.g. saffron, gladiolus.

(iv)Bulb – is a modified underground stem in the form of a disc-like structure that bears fleshy leaves that store food material, e.g. onion, lilies.

(v)Cladophyll – is a modification of the stem into a large, flat green and fleshy structure that bears leaves into spines. Such stems carry out the functions of leaves, e.g. cactus.

(vi)Tendril – an aerial modification of the stem where the stem becomes a long, slender, coiling structure serving as an organ of attachment for certain climbing plants. It helps the plant to climb up the support, such as grapes and cucurbits.

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