bryophyta

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Structure and reproduction in general

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Presentation Transcript

BRYOPHyTA : 

BRYOPHyTA Structure & Reproduction Dr Ashok Bendre

Characters : 

Characters How does the group Bryophyta differ from Thallophyta ? Presence of multicellular and jacketed sex organs. Formation of embryo. Gametophytes and sporophytes morphologically distinct. Sporophyte dependent on gametophyte.

The Unique Features : 

The Unique Features 1. Also known as Archegoniate Embryophyta Atracheata Amphibians of Plant Kingdom 2. The first land inhabiting plants 3. Sporophyte remains attached to gametophyte

Where do the Bryophytes occur ? : 

Where do the Bryophytes occur ? Mostly terrestrial Aquatic Ricciocarpus natans

Slide 5: 

Some are epiphytic Frullania on tree trunk

Others are saprophytes : 

Others are saprophytes Cryptothallus mirabilis Buxbaumia aphylla (liverwort) ( moss )

Gametophyte : 

Gametophyte Thallose Foliose ( Marchantia-Liverwort) (Fontinalis-Moss)

Reproduction : 

Reproduction There are two methods 1. Vegetative by tubers,gemmae, protonema,etc. 2. Sexual Antheridia & archegonia

Sexual method : 

Sexual method Oogamous where male gametes are motile and the female ( egg ) is non-motile. Male sex organ is a jacketed and multicellular structure Female sex organ also has a jacket and is multicellular

Antheridium : 

Antheridium It is made of 1. Multicellular stalk 2. Body has an an outer wall (jacket) of single layer of cells that encloses androcytes and finally flagellated antherozoids ( male gametes).

Archegonium : 

Archegonium It consists of 1.multicellular stalk 2.Neck Neck cells Cover cells Neck canal cells 3.Ventre Wall Ventre canal cell Egg cell

Fertilisation & Embryo : 

Fertilisation & Embryo Fertilization requires water Motile male gamete reaches archegonium, only one enters and fuses with the egg. Fusion product called zygote that divides to form embryo ( diploid). Embryo develops into a sporophyte- may or may not be differentiated. Spores produced in sporophyte after meiosis in spore mother cells.

Spore and its germination : 

Spore and its germination Spore is the first cell of new gametophytic generation. Germinates to produce a new generation of gametophyte

Classification : 

Classification

Economic Importance : 

Economic Importance Act as soil binders and thus help check soil erosion. Form one of the initial seres in plant succssion. Sphagnum-Bog moss, peat moss, turf moss, survives acidic conditions, hyaline cells retain water and hence used as packing material

Funaria – Life Cycle : 

Funaria – Life Cycle Systematic position Kingdom - Plantae Sub-kingdom - Embryophyta Phylum - Bryophyta Class - Bryopsida Order - Funariales Family - Funariaceae Genus - Funaria

Gametophyte of Funaria : 

Gametophyte of Funaria Foliose Rhizoids – septa oblique Axis –erect, branched Leaves – spirally arranged, sessile

Vegetative Reproduction : 

Vegetative Reproduction Fragmentation of primary protonema Secondary protonema Gemmae Bulbils Apospory

Sexual Reproduction: Archegonium : 

Sexual Reproduction: Archegonium Archegonium consists of 1.6 vertical rows of neck cells 2.4 cover cells 3.Ventre consisting of A ventre canal cell An egg cell

Sexual reproduction: Antheridium : 

Sexual reproduction: Antheridium Antheridium It consists of An outer wall made of single layer of cells Androcytes which later form biflagellate antherozoids.

Sexual Reproduction :Fertilisation : 

Sexual Reproduction :Fertilisation Requires water Cells of archegonial neck disintegrate;the mucilage rich in sugar Antherozoids attracted by sugar One enters the ventre,fuses and forms zygote- the first cell of sporophyte

Sporophyte : 

Sporophyte Zygote divides mitotically and develops into an embryo Embryo grows and finally differentiates into a well developed sporophyte It consists of 1.Foot, 2.Seta and 3. Capsule

Sporophyte: The foot : 

Sporophyte: The foot The foot remains embedded in the gametophytic tissue Draws water and minerals Hence, sporophyte is partially dependent on gametophyte

Sporophyte: The Seta : 

Sporophyte: The Seta It is a long stalk Capsule at its tip Twists when mature Helps in spore dispersal

Sporophyte : The Capsule : 

Sporophyte : The Capsule Capsule is made of 1.Apophysis 2.Theca and 3.Upper part The sporophyte is covered with calyptra – remnant of ventre wall ( gametophytic).

Capsule : Apophysis : 

Capsule : Apophysis Lower part of the capsule Presence of stomata and chloroplasts allow photosynthesis. Hence though foot derives water & minerals from gametophyte, food is produced in apophysis Therefore, Sporophyte is partially independent or partially dependent on gametophyte.

Capsule : Theca : 

Capsule : Theca Columella in the centre helps conduction. Spore sac has spore mother cells which divide meiotically to produce haploid spores

Capsule : The Upper Part : 

Capsule : The Upper Part After removal of operculum peristome is exposed Peristome of Funaria has 32 teeth in two rows. Outer 16 teeth show thick bands and are hygroscopic Help in spore dispersal

Capsule : The Peristome : 

Capsule : The Peristome Peristomeal teeth showing thick transverse bands and triangular shape

Spore : Germination into Protonema : 

Spore : Germination into Protonema Spore is the first cell of the next generation gametophyte. Germinates to produce form green filament called protonema typical of mosses only) Later buds on protonema develop into leafy gametophyte

Funaria: Life Cycle : 

Funaria: Life Cycle