Sporangium and Different Spore Types

Sporangium

Sporangium has been derived from modern Latin word “spora” means spores and classical Greek word “angeion” which means vessel. So, sac like structure, which develops spores as tetrad after meiosis of spore mother cell.
Spore: Reproductive unit of a plant body which upon germination to form a new plant body.

Sporangium and Different Spore Types

Sporangium

Types of Sporangium (Depending upon Organization with Position, Shape, Source)

Synangium

StrobilusSorus

Sporocarp

Present at apex of Branchlet also known as fertile telome.

Trilocular, spherical / oval in shape.

Depending upon source.  It has two types:

Group of sporangium in spherical form present at either adaxial or abaxial surface of megasporophylls.

Ellipsoidal fruiting body containing with sporangia, present at the base of petiole of megaphyll.

For example

Psilotum

Rhynia

Aggregation of Micro

Sporophylls into compact cone like structure at terminal position of main stem.

Aggregation of sporangiophore into compact cone like structure at terminal position of main stem.

For example:

-Adaxial surface of megasporophylls

Polipodieceae,

Eusporangiate

For example:

Marsilea

Salvinia

azolla

Trilocular /three dimensional with oval or spherical shape structure, containing one sporangium in one locus, present at terminal position in each one locus, present at terminal position of branchlet od dichotomous sporophytic plant body.

For Example:

Lycopodium

Selaginella

With respect to development Eusporangiate.

For Example:

Equisetum

With respect to development is Eusporangiate.

-Abaxial surface of megasporophylls

Fern, Eusporangiate.

With respect to development is leptosporangiate.

With respect to development is eusporangiate.

 

 

 

 

Types of Sporangium

Depending upon presence and absence of sporangia

1: Sterile Leaf/Vegetative Leaf

Without sporangia

Depending upon chlorophyll it has two types

Types of photosynthetic leaves

2: Fertile leaf/Sporophylls/Reproductive leaf

Depending upon nature of leave

Homosporophyll

Micro- Homosporophyll

Mega- Homosporophyll

Simple leaf without leaflets

Compound leaf without leaflets.
Sessile leaf without petiole

Pinnate leaf with rachis.

Small in size as compared to stem

Large in size as compared to stem.
Sporangium with same size of spores, present at axial of leaf.

Sporangium with same size of spores as sorus, present at either Adaxial or Abaxial surface of leaf.

Present at terminal position of stem as strobilus

For example:

Adiantum (marginal side)

Pteris (middle position)

Dryopteris (middle position)

Pteridium (middle position)

Polypodiaceae (Adaxial side)

 

For example: lycopodium

 

Heterosporophyll

Micro- Heterosporophyll

Mega-Heterosporophyll

Simple leaf without leaflets

It is absent in pteridophytes.

Sessile leaf without petiole

 

Small in size as compared to stem

 

Sporangium with different size of spores present in axial of leaf.

 

Present as cone at terminal position of stem.

 

For example: Selleginella

 

Majority of pteridophytes show homosporus condition. All bryophytes show homosporus condition.

Homospory

The condition, in which sporophylls contains same size of sporangia is called as Homospory.

Phyllospory

The condition, in which there is presence of sporangia either at dorsal or ventral side leaf is known as Phyllospory. E.g. Polypodiaceae

Heterospory

The condition in which sporophylls contains different types of sporangia is called as Heterospory.

Stachiospory /Stachiosporous Condition

The condition in which there is presence of sporangia in axial of leaf and stem is known as Stachiospory /Stachiosporous condition. E.g. Selaginella, lycopodium.

Read also:- Female Cone Lecture

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