Tag: root - external morphology

In dicot roots, the pith is either absent or not well developed. On the other hand in case of monocot root, we find a well developed pith across all the genera.
Thus, the correct answer is option C.

Grasses are the monocotyledonous plants. These plants possess the adventitious or the fibrous type of root system. There are many fine thread-like branches which develop from any other part of the plant rather than the radicle. These type of roots do not grow much deeper but spread in the region widely to provide support the plant.

The monocotyledonous plants possess the adventitious or the fibrous type of root system. There are many fine thread-like branches which develop from any other part of the plant rather than the radicle. These type of roots do not grow much deeper but spread in the region widely to provide support the plant.

Adventitious roots do not arise from the radical of the seed. Instead, they can originate from the plumule parts such as stem, branches, leaves, or old woody roots of the plants. Hence, they are termed as adventitious. They commonly occur in monocots and pteridophytes. 

The adventitious roots found in the epiphytes are known as the epiphytic root. These roots hang freely in the air and absorb the moisture from the air by a special type of tissue called as velamen. Epiphytic plants are sometimes called as air plants because, they do not have roots in the soil. For example, Vanda.

Sweet potato and turnip are root modifications. Sweet potato is a type of adventitious roots, which is modified to store food materials. The edible tuberous root is long and tapered. Turnip is a type of tap root. Ginger, potato, Colocasia are underground stem modifications for food storage. Both have the same function but different structure and thus are called as homologous.

When the adventitious roots modified for aerial support is called as prop roots. Prop roots give mechanical support to the aerial branches. The lateral branches grow vertically downward into the soil and act as pillars. Prop or pillar or columnar roots are pillar-like roots which give extra mechanical support to heavy stem branches, e.g., banyan tree. 

Vegetative propagation by roots takes place in modified roots called as tubers. Buds grow from the base of the stem into new plants. These roots are swollen for food storage. For example, Sweet potato, Asparagus, Tapioca and Dahlia.

Fasciculated roots are the type of modified adventitious root. They are tuberous root which become thick due to storage of food. These types of roots occur in clusters from the base of the stem, e.g., Asparagus, Tapioca, Dahlia.