Botany lecture notes

Difference between Leptosporangium and Eusporangium (Comparison Table)


Leptosporangium vs eusporangium Development

Eusporangia vs Leptosporangia
(Similarities and Differences between Leptosporangia and Eusporangia of Pteridophytes)

Sporangia are the specialized spore producing structures found in plants. In Pteridophytes, two types of sporangia are present. The two types of sporangia are (1) Eusporangium and (2) Leptosporangium. This classification is proposed by Goebel in 1881 based on the developmental pattern of sporangia. The spores produced in the Eusporangium are called eusporangiospores and those produced in the Leptosporangium are called leptosporangiospores.

Eusporangium: The sporangium develops from a GROUP of INITIAL cells and such a development is called development.

Leptosporangium: The sporangium develops from a SINGLE INITIAL cell and such a development is called Leptosporangiate development.

The present post describes the Similarities and Differences between a Eusporangium and Leptosporangium.

Similarities between Eusporangium and Leptosporangium

Ø  Both Eusporangia and Leptosporangia are the spore producing structures in vascular plants.

Ø  Both are formed on the sporophyll (a specialized leaf) of the diploid sporophytic plant.

Ø  Both produce haploid spores after meiosis.

Ø  The first division of the initials of both sporangia is periclinal (transverse division).

Difference between Eusporangium and Leptosporangium

Continue reading

Botany lecture notes

Pteridophytes: General Characters (with Power Point Presentation – PPT)


General Characters of Pteridophytes

Pteridophytes General Characteristics
(General Characters of Pteridophytes – The Vascular Cryptogams)

Pteridophytes are plants with Feather like Leaves

Pteridophytes are a group of primitive land plants belongs to the Cryptogams. They are the first evolved plant group with vascular tissue system for the conduction of water and food materials. Due to the presence of vascular tissue, they are called as Vascular Cryptogams. The term Pteridophyte is derived from two words ‘Pteron’ meaning feather and ‘phyton’ meaning plant. Thus, Pteridophytes are the plants with Feather-like leaves. Pteridophytes occupy the intermediate position between Bryophytes and Phanerogams (seed plants). The important characteristics of Pteridophytes are summarized below:

Pteridophyta General CharactersØ  The division Pteridophyta includes primitive living and fossil vascular plants.

Ø  They were originated in the Silurian period and flourished in the Devonian period.

Ø  They are known as ‘Vascular Cryptogams’ – cryptogams with vascular system.

Ø  They show heteromorphic alternation of generation with prominent Sporophytic and Gametophytic phases.

Ø  The main plant body of Pteridophyte is the sporophytic plant (diploid).

Ø  The gametophytic and sporophytic generations are two independent plants (not physically connected).

Habit and Habitat of Pteridophytes

Ø  Pteridophytes show much variation in form, size, and habitat.

Continue reading

Botany lecture notes

Types of Stelar Systems and its Evolution in Pteridophytes and Higher Plants with PPT


types of steles in pteridophytes

Stelar Evolution in Vascular Plants
(Origin and Evolution of Stele in Pteridophytes and Higher Plants)

What is stele? What are the components of stele?

Ø  Stele is the central cylinder or core of vascular tissue in higher plants.

Ø  The stele consists of xylem, phloem, pericycle and medullary rays and pith if present.

Ø  The term ‘stele’ was for the first time used by Van Tieghem and Douliot in 1886 in their ‘Stelar Theory’.

What is ‘stellar theory’?

Ø  Proposed by Van Tieghem and Douliot in 1886.

Ø  Major highlights in stellar theory are:

$.  The stele is a real entity and present universally in all axis of higher plants.

$.  The primary components of stele are xylem and phloem.

$.  Tissues like pericycle, medullary rays and pith are also the components of stele.

$.  ‘Stelar theory’ also says that the cortex and the stele are the two fundamental parts of a shoot system.

$.  Both these components (stele and cortex) are separated by the endodermis.

$.  In higher vascular plants (Pteridophytes, Gymnosperms and Angiosperms), the leaf traces are large, and it appears that they play an important role in the vascular system of the axis.

$.  The whole set-up of leaf traces appears as a composite structure in these plants.

$.  Such composite structures do not remain within the limits of stellar theory of Van Tieghem and Douliot.

What are the different types of steles in plants (Pteridophytes and higher plants)?

Ø  On the basis of ontogeny and phylogeney, there are THREE broad categories of steles in vascular plants.

Ø  They are:

(1).  Protostele

(2).  Siphonostele

(3).  Solenostele

Continue reading