Protophloem vs Metaphloem

Phloem is a tissue that is responsible for the transportation of food material from the photosynthetic organ to different parts of the plant. A phloem consists of companion cells, sieve tubes, phloem fibres and phloem parenchyma cells. The phloem undergoes primary and secondary growth. As a result of primary growth, protophloem and metaphloem are formed by the differentiation of procambium. Let us look at the differences between protophloem and metaphloem:

Protophloem

Metaphloem

Definition

Protophloems are the first structures that are produced as a result of primary growth in the phloem.

Metaphloems are formed after the formation of protophloem.

Growth

It is formed even before the maturation of plant organs.

It is formed after the maturation of plant organs.

Composition

It is composed of sieve tubes, phloem fibres and phloem parenchyma.

It is composed of sieve tubes, phloem fibres, companion cells and phloem parenchyma.

Companion Cells

Companion cells are absent.

Companion cells are present.

Size of Cells

The protophloems have smaller cells and are therefore less prominent structures.

They have bigger cells and are more prominent structures.

Sieve Elements

The sieve elements are narrow and thin.

The sieve elements are wide and long.

Life

They are short-lived and get crushed in the later stages of growth.

They are longer living than protophloem but may get crushed during secondary growth.

Stretchability

The cells are more stretchable.

The cells are less stretchable.

Explore BYJU’S Biology to learn more.

Also read:

FAQs

How do you identify protophloem?

A protophloem can be identified by the presence of small and narrow cells.

Is metaphloem a primary phloem?

Yes, metaphloem is a primary phloem, formed due to the differentiation of procambium.

Are companion cells present in protophloem?

No, companion cells are not present in protophloem.

What is primary and secondary phloem?

Primary phloem is the first growth that occurs in the phloem as a result of differentiation of procambium; secondary growth takes place after the primary growth due to the differentiation of cork cambium.

Leave a Comment

Your Mobile number and Email id will not be published. Required fields are marked *

*

*

BOOK

Free Class