Question

type of protostele???

Answer 1

There are three basic types of protostele: haplostele
actinostele
plectostele
Siphonostele

Answer 2

ANSWER :-

Protostele consists of four different types within itself. The types are as follows-

• Haplostele- Here, solid round central core of xylem is surrounded by phloemand pericycle. Examples of species or cases where haplosteles are found are as follows- Selaginella kraussiana, Rhynia, Horneophyton, Cooksonia, etc.
• Actinostele- Here, central xylem is star shaped with radiating arms and phloem is present in separate patches. Examples of species or cases where actinosteles are found are as follows- Asteroxylon, Lycopodium serratum, Psilotum, etc.
• Plectostele- Here, xylem is present in the form of separate plates and phloem is present between these xylem plates. Example of species or cases where plectosteles are found are as follows- Lycopodium clavatum and Lycopodium volubile.
• Mixed Protostele- Here, xylem is present in the form of discrete units embedded in phloem. Example of species or case where mixed protostele is found is as follows- Lycopodium cernuum.

Extra Information-

Protostele is referred to as the most primitive type of stele and all of the other kind of steles have been derived from it. -

• In the case of this kind of stele, the pith is completely absent. 
• This primitive type of stele is found in species or cases such as Lygodium, Psilotum, Selaginella, etc.