funaria(moss),bryophyta

funaria(moss)

Classification:

Divinsion: Bryophyta

Class: bryopsida (moss)

Order: Funariales

Family: Funariaceae

Genus: Funaria

Species: Hygrometrica

Habitat

• It’s very common moss, widely distributed throughout the world.
• ~117 sp. Worldwide
• 15 sp. In India
• It usually grows on group as close tufts, frequently on recently burnt land where ashes of plants are present.
• Also found on rocks, walls or crevices as mats.

·         Structure of gametophytes :

·         Gametophyte shows two distinct phases.

1.       Protonema= prostrate filamenous, alga- like structure.

2.       Gametophores= upright leafy persistent moss plant.

·         Gametophores are about 1.3 cm high.

·         Consists of slender, erect, radial stem covered with small, simple leaves.

·         Stem: monopodially branched, branches grow as erect structure.

·         At the base of gametophores numerous-branched-slender, multicellular rhizoids are present.

·         Leaves: spirally arranged, 3/8 phyllotaxy ovate shape, attached to stem by broad base.

Lower leaves are smaller-scattered upper/young leaves are larger and crowded at the tip of stem.

·         Internal structure:

1.       Stem: well differentiated tissues present.

·         3 parts =

a)      Central cylinder

b)      Cortex

c)       Epidermis

.                  Central cylinder: consists of long, narrow, thin walled cells, protoplast absent.

              Cortex: it covers central cylinder, cells contain chloroplast thicker & reddish-brown cells in outer        region, thin walled cells towards inside.

C.              Epidermis: one cell layer, contain chlorophyll, stomata absent.

2.       Leaves:

• ·         Well defined midrib present.
• ·         Wing (blade) on either side of midrib is single cell layered.
• ·         In centre of midrib, narrow thin walled conducting strand is present.
• ·         Blade on either side contains polygonal cells with numerous large chloroplasts.
• ·          Chloroplasts here continue to multiply even after cell division, hence this leaf cells are used for chloroplast related studies.

Reproduction

• ·         It happens only through sexual mode of reproduction.
• ·         F.hygrometrica is monoencious & or autoecious (male and female are separate branches of same plant).
• ·         The main shoot (apex) bears a group of antheridia at tip = male branch female branch develops later as lateral branch grows higher than male branch.

Antheridia (male)

• ·         Short massive stalk, body ~0.25 mm club shaped body.
• ·         Jackets contain chloroplasts at young and turn orange while mature.
• ·         Tip of body contain 2-4 cells of thick wall known as operculum cells.
• ·         Central parts contain antherozoids.

·         Paraphysis: hair like strive structure present around antheridia cluster.

• ·         It fuctions for providing moisture to antheridium and also photosynthesis.
• ·         Release of antheridia tnakes place by presence of water.
• ·         Operculum cell breaks and antherozoids are released.

Archegonia (female)        

• Multiple archegonia develop on female branch at tip.
• ·         Leaves surrounding it known as “perichaetial leaves”.
• ·         Within these leaves it presence of numerous archegonia surrounded by Paraphysis.
• ·         Mature archegonia has-long massive stalk.
• ·         Jacket is double layered.
• ·         Neck is single layered. Have ~6 neck canal cells. Slightly enlarged ventral canal cell.
• ·         Inside chamber, will be presence of egg cell.
• ·         At maturity, neck canal cells and Vcc disintegrate and form mucilaginous mass cover cells are removed leaving passage for antherozoids.

Sporophyte

  è                     mature sporogonium is composed of:

1.       Foot

2.       Seta

3.       Capsule

1)      Foot: foot is poorly developed small, dagger-like conical structure embedded in apex.

·         It only contains parenchymatrus cells.

2)      Seta: seta is long, slender, twisted structure.

·         It’s strand like structure which conducts water and food from thallus through foot and supply to the developing capsule.

3)      Capsule: capsule is present at tip of seta.

         i.            Apophysis: its lower most portion of capsule.

·         Contain central strand of ending seta.

·         Surrounding seta, it has chloroplast containing photosynthetic cells is which provide food to growing capsule.

·         Outer most layer of cells which is epidermis which covers whole capsule. Only apophysis region, epidermis contains stomata.

       ii.           heca: urn-shaped, middle fertile region of capsule.

·  spore   sac has:

a.       Outer spore sac wall

b.      Inner spore sac wall

c.       Spore sac

·         Central region is made of sterile strong cells = columella which provide mechanical strength to capsule.    It has 2 layered hypodermis, spore sac is surrounded by air space connected to rest tissues by trabeculae.

• Diatoms(algae)

      iii.            Operculum: cap-like structure placed on theca.

·         Contain annulus & peristome.

·         Through this structure, spores are dispersed.

·         Capsule here dehisce by work of hygroscopic peristome.

·         During presence of moisture, the peristome opens operculum and spores come out from spore sac.

·         Spore germinates during favorable condition to give rise to either male/female gametophyte.