CHAPTER 6 :- PLANT WATER RELATION

Parts of a root : 

In a typical root, there are five distinctive zones starting from apex to the base.

1. Root Cap. 

1) It is a cap like covering over the root tip for protection against function from soil particles. 

2) Root cap also takes part in graviperception. 

3) Multiple root cap occurs in the aerial root of Pandanus. 

4) Root cap is absent in most mangrove plants. 

5) Aquatic roots often possess root pockets instead of root caps, e.g., Pistia, Eichhornia. 

6) They are non-renewable and function as balancers.

2. Growing Point. 

1) It is hardly 1 mm long region of meristematic cells. 

2) The growing point produces new cells for root cap and basal parts. 

3) It is, therefore, the zone of cell formation.

3. Zone of Elongation. 

1) It is 4-8 mm long portion behind the tip. 

2) Here cells elongate rapidly.

4. Root Hair Zone. 

1) The region is 1-6 cm long. 

2) Xylem and phloem differentiate here (hence cell maturation zone). 

3) Outer cells give rise to tubular root hairs for increasing absorptive area.

5. Zone of Mature Cells. Bulk of the root is made of it.