Question

What is meant by modification of rots what type of modification?

Answer 1

modification of root means function of roots other then absorbing water.
like: for storage - conical roots(ex=carrot(scientific name: daucas carota)) , fusiform root(radish(Raphanus sativum)), napiform roots(ex=turnip), tuberous root(ex=merabilis jalapa), nodulated root(ex=pea(pisum sativum ) .
similarly for respiration
pneumatophores (ex= mangroves, rhizobium)
roots having pneumathodes(small pores also known as lenticles) ,these roots comes out of soil for respiration.
these all are tap root modifications
there are also adventitious root modifications.

Answer 2

$\huge{\mathfrak{\underline{Root\ modifications }}}$

Some plants perform special functions in order to perform the special functions. Some root modifications are given below

$\huge{\mathfrak{\underline{Storage \Roots }}}$

The roots which store food material and become swollen are called storage roots or tuberous roots

Ex: Carrot, turnip, radish, Sweet potato, asparagus

$\huge{\mathfrak{\underline{Prop\roots}}}$

The Adventious roots produced from branches are called prop or pillar roots

$\huge{\mathfrak{\underline{Stilt\roots }}}$

The roots which arise from the lower nodes of the stem are called stilt roots or brace roots

ex: Maize, sugar cane

$\huge{\mathfrak{\underline{Velamen\Roots}}}$

The plants which grow on the branch of other tress are called epiphytes. The long branched hanging Adventious roots of epiphytes are called Velamen roots

ex:Vanda