Question

Mention and explain the types of underground modifications of root

Answer 1

Underground stems are modified plant structures that derive from stem tissue but exist under the soil surface.[1] They function as storage tissues for food and nutrients, propagation of new clones, and perennation (survival from one growing season to the next).[2] Types include bulbs, corms, rhizomes, stolon, spindle - shaped and tubers

Plants have two axes of growth, which can be best seen from seed germination and growth. Seedlings develop two structures or axes of growth, one that develops upward out of the soil, called stems, and structures that develop downward which are called roots. The roots are modified to have root hairs and branch indiscriminately with cells that take in water and nutrients, while the stems are modified to move water and nutrients to and from the leaves and flowers. Stems have nodes with buds where leaves and flowers arise at specific locations, while roots do not. Plants use under ground stems to multiply their numbers by asexual reproduction and to survive from one year to the next, usually over a period of dormancy.[3] Some plants produce stems modified to store energy and preserve a location of potential growth to survive a cold or dry period which normally is a period of inactive growth, and when that period is over the plants resume new growth from the underground stems

Answer 2

$\huge\textbf{Modification of Roots...}$

Roots are modified on the basis of :-

$\textbf{1) Support.}$

$\textbf{2) Respiration.}$

$\textbf{3) Storage.}$
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$\textbf{1) Support :}$ The stems of maize and sugarcane have supporting roots coming out of the lower nodes of the stem. These roots are Known as still roots.

$\textbf{2) Respiration :}$ In some plants such as Rhizophora grow in swampy areas, many roots come out of the ground and grow vertically upwards. Such roots are called Pneumatophores help to get oxygen for oxygen.

$\textbf{3) Storage :}$ In some plants the primary tap roots are modified for storing reserve food material. The storage roots are swollen and assume various forms.

$\textbf{a) Conical :}$ The swollen root is board at the base and tapers gradually towards the apex giving a shape of Conical. 
Ex :- Carrot.

$\textbf{b) Fusiform :}$ The root is swollen at the middle and narrow towards both it's base and apex giving a shape of spindle. 
Ex :- Radish.

$\textbf{c) Napiform :}$ The root is nearly globular or spherical in shape. The basal portion of root is much swollen which suddenly tapers towards the apex giving a top shaped. 
Ex :- Turnip or beet.

$\textbf{d) Tuberous :}$ The storage food having no fixed shape.
Ex :- Mirabilis Jalapa.
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