. Discuss two type of phloem
1. Primary phloem:
a. It is formed by procambium during primary growth.
b. It may or may not show differentiation into protophloem (consists of sieve elements and parenchyma) and metaphloem (develop after protophloem and consists of sieve elements, parenchyma and fiber).
c. During the primary growth the protophloem elements are curshed by the surrounding tissues and disappear. This process is known as obliteration
d. Primary phloem consists of sieve elements, parenchyma and fibre.
2. Secondary Phloem:
a. It is produced during secondary growth by vascular cambium.
b. It consists of the following elements :
c. Sieve elements
d. Companion cells
e. Phloem parenchyma
Phloem fibres or bast fibres