Question

define actinostele? give example?​

Answer 1

ANSWER :-

Definition of Actinostele-

Actinostele is referred to as the type of protostele in the case of which, 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- 

1. Asteroxylon,
2. Lycopodium serratum,
3. Psilotum, etc.

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. -

1. In the case of this kind of stele, the pith is completely absent. 
2. This primitive type of stele is found in Lygodium, Psilotum, Selaginella, etc.

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

1. 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.
2. Actinostele- defined in the answer already.
3. 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.
4. 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.

Answer 2

Answer:

The central core of xylem in a protostele is star-shaped or lobed in cross-section.

Explanation:

• It is a vascular core  with alternating or radial groups of xylem and phloem within a pericycle.

• Or The central core of xylem in a protostele is star-shaped or lobed in cross-section.

•    For Example - Lycopodium serratum

• Lycopodium serratum is a plant that is extensively used in herbal   medicine and is thought to have anti-cancer qualities

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