Reproduction in pteridophyta and bryophyta science Class 9 Junior high school

Reproduction in pteridophyta and bryophyta biology Class 9 Junior high school
Reproduction in Pteridophytes:
(i) Reproduction takes place by means of spores which are produced inside sporangia.
(ii) The development of the sporangium may be leptosporangiate (sporangium originates from a single cell) or eusporangiate (sporangium develops from a group of cells).
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(iii) Sporangia may be borne either on stem or leaves. On the stem they may be terminal (e.g., Rhynia) or lateral (e.g., Lycopodium). On the leaves (sporophylls) they may be ventral, marginal (Pteris, Adiantum) or dorsal (e.g., Polypodiceae). In Equisetum the sporangia are borne on special structures called sporangiophores which constitute a cone. In Marsilea, Azolla, Salvinia sporangia are produced in sporocarps.
(iv) Spores on germination give rise to multicellular gametophytic bodies called prothalli (sing. prothallus).
(v) In homosporous Pteridophytes prothalli are monoecious (antheridia and archegonia develop on the same prothallus). In heterosporous species prothalli are always dioecious. Microspores on germination give rise to male prothalli and megaspores to the female prothalli.
(vi) Antheridia and archegonia are developed on prothalli.
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(vii) Antheridium is surrounded by a single layered sterile jacket.
(viii) Archegonium consists of four vertical rows of neck cells, 1-2 neck canal cells, ventral canal cell and egg.
(ix) Antherozoids are unicellular, biflagellate (e.g., Selaginella) or multiflagellate (e.g., Equisetum and ferns) and motile.
(x) Antherozoids are attracted towards the neck of the archegonium chemotactically by certain substances like malic acid) present in the mucilaginous substance formed by the degeneration of neck canal cells and venter canal cell.
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(xi) Water is essential for fertilization (zooidogamous). Therefore, Pteridophytes are also known as amphibians of the plant kingdom.
(xii) Fertilization results in the formation of zygote or oospore, which ultimately develops into well-developed sporophyte.
(xiii) The fertilized egg divides transversely or vertically. Another cross wall forms a quadrant stage producing stem, leaf, foot and root.
(xiv) Plants show heteromorphic alternation of generation. The main plant body is sporophytic and forms a dominant phase in the life cycle.
Characteristics of Bryophytes
As stated before, the defining feature of bryophytes is that they are non-vascular plants. Other important bryophytes characteristics are as follows:
Plants in this category do not have roots but have crude stems and leaves.
They have “rhizoids” instead of roots which helps the plant to anchor to surface.
These roots or rhizoids do not absorb nutrients like other usual plant roots.
Mosses release spores from their leaves which travels by water and make new mosses in new locations.
Water is very essential for mosses to grow and spread. They can entirely dry out and survive. When in contact with water, they again revive and continue growi

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