LIFE CYCLE FUNARIA PDF

Rhizoids arise from the base of the axis. They are slender, branched, and multicellular and have oblique septa. Axis is 1—3 cm. Each branch is extra axillary i. Cuticle and stomata are absent Fig.

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Rhizoids arise from the base of the axis. They are slender, branched, and multicellular and have oblique septa. Axis is 1—3 cm. Each branch is extra axillary i. Cuticle and stomata are absent Fig. It is made up to parenchymatous cells. Younger part of the cortex contains chloroplasts but in the older part they are lacking. At maturity few outer layers of cortex become thick walled and are reddish brown in colour but those of the inner layers become thin walled.

These cells are now commonly called as hydroids. Conducting strand besides providing a certain amount of mechanical support, functions in the upward conduction of water and solutes. The cells contain many large and prominent chloroplasts Fig. The central part of the mid rib has narrow conducting strand of thick walled cells which help in conduction. Funaria reproduces by vegetative and sexual methods. By multiplication of primary protonema: In Funaria, spores on germination form a branched, filamentous, multicellular structure.

In it certain colourless separation cells are formed by intercalary divisions. These cells die out and break up the protonema into single cell or many celled fragments. These fragments grow into new protonemata which bear buds.

Each bud develops into a leafy gametophore. It is similar to primary protonema and develops into leafy gametophore. By Gemmae: During unfavorable conditions, the terminal cells of the protonemal branches divide by transverse, longitudinal divisions and form green multicellular bodies of cells Fig. These are called gemmae. At maturity gemmae become slightly reddish brown in colour. On the return of favourable conditions gemmae germinate and form new plants.

By Bulbils: When such gemmae like structures are produced on rhizoids inside the substratum, these are called bulbils. These are devoid of chloroplasts but capable of developing into leafy individuals under favourable conditions. Apospory: Development of gametophyte from sporophyte without the formation of spores is known as apospory. Any vegetative cell of the sporophyte may form green protonemal filaments which bear lateral buds.

These buds later develop into leafy gametophores. The gametophores thus formed are diploid. Sexual reproduction in such gametophores results in the formation of tetraploid 4n zygote. The sporophytes from tetraploid are sterile because they are not capable of bearing spores. Male reproductive structure is known as antheridium and female as archegonium. Funaria is monoecious having male and female sex organs on the same thallus and autoicous antheridia and archegonia develop on separate branches of the same thallus.

Sex organs are borne on leafy gametophores in terminal clusters. The main shoot of the leafy gametophore bears antheridia and act as male branch. Female branch develops as a lateral outgrowth from the base of the male branch and bears archegonia. It grows higher than the male branch. Funaria is protandrous antheridia mature before the archegonia. It ensures the cross fertilization. Male Branch or Antheridiophore: Longitudinal section L.

It bears large number of reddish brown or orange antheridia in different stages of development. Projected antheridia are surrounded by a rosette of spreading leaves called perigonial leaves. The antheridial cluster with surrounding perigonial leaves is called perigonium.

The antheridia are intermingled with large number of sterile hair like club shaped structures called paraphyses Sing, paraphysis Fig. Paraphyses store water, protect developing antheridia, help in photosynthesis and dehiscence of antheridia. Structure of an Antheridium: The antheridium is club shaped.

It can be differentiated into two parts: a Short multicellular stalk b Body of antheridium Fig. Body of antheridium has sterile, single layered jacket of polyhedral flattened cells. When young the cells of the jacket contain chloroplasts which turn orange or reddish brown at maturity. Jacket encloses a large number of androcytes antherozoid mother cells.

At maturity the distal end of the antheridium bears one or two thick walled, colourless cells called operculum. The opercular cells become mucilaginous, absorb water and swell, break connections with the neighbouring cells and form a narrow pore. Androcytes ooze out in the form of a viscous fluid through this pore.

Development of Antheridium: Antheridium develops from a single superficial slightly projected cell. It is called antheridial initial. It develops at the apex of the male branch. It divides by a transverse division to form a basal cell and an outer cell Fig. The basal cell form the embedded portion of the stalk. The outer cell forms the entire antheridium and is known as antheridial mother cell. It divides by transverse divisions to form a short filament of cells Fig.

The lower cells form the lower part of the stalk of the antheridium. The terminal cell of the filament divides by two vertical intersecting walls, thus an apical cell with two cutting faces is differentiated Fig. The apical cell cuts segments in two rows in regular alternate sequence. In this way segments cut off Fig. Simultaneously when the apical cell is dividing, the third or fourth segments below the apical cell, starts dividing from base, upwards by diagonal vertical walls.

The first wall divides the segment into two cells of unequal size. Small cell is called jacket initial Fig. Larger cell further divides periclinally into an inner large primary androgonial cell Fig. In a transverse section T. Such type of divisions takes place in all the upper segments except the apical cell which develops into operculum. All the jacket initials divide only by anticlinal divisions to form a single layered wall of antheridium Fig. Primary androgonial cells divide and re-divide to form the androcyte mother cells.

The cells of the last cell generation are called androcyte mother cells. Each androcyte mother cell divides further and form two androcytes. Each androcyte produces a single biflagellate sperm or antherozoid or spermatozoid. Each antherozoid is elongated, spirally coiled, bi-flagellated structure Fig. Female Branch or Archegoniphore: The female branch arises from the base of the male branch. Longitudinal section L. The terminal cell of paraphyses is not swollen.

The archegonial cluster with the surrounding perichaetial leaves is called perichaetium. Structure of an Archegonium: A mature archegonium is flask shaped structure. It remains attached to the female branch by a massive stalk. It consists upper elongated slender neck and basal globular portion called venter Fig. The neck is slightly tubular, twisted, single layered and consists of six vertical rows of neck cells, which enclose an axial row of ten or more neck canal cells.

The venter wall is two layered and encloses venter canal cell and egg cell. Venter canal cell is situated just below the neck canal cells. Development of Archegonium: Archegonium develops from a single superficial cell called the archegonial initial Fig. It differentiates at the apex of the female branch. Archegonial initial divides by transverse division to form the basal cell or stalk cell and a terminal cell. The basal cell divides and re-divides to form the stalk of the archegonium. The terminal cell functions as archegonial mother cell Fig.

It divides by three intersecting walls forming three peripheral cells enclosing a tetrahedral axial cell Fig. The peripheral cells divide anticlinally to form a single layered wall of venter which later becomes two layered. The axial cell divides, transversely to form an outer primary cover cell and inner central cell Fig.

The outer primary cover cell functions as aplical cell with four cutting faces three lateral and one basal. It cuts off three lateral segments and one basal segment. Each lateral segment divides by a vertical wall so that the six rows of cells form the neck of the archegonium Fig.

Each basal cell adds to neck canal cell. The inner central cell divides by transverse division into an outer primary neck canal cell and an inner primary venter cell Fig.

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Taran Mosses Overview A cross section through the upper portion of the young sporogonium shows a two identical segments Fig. Share buttons are a little bit lower. Lief entire sporophyte is differentiated by the activity of these two apical cells. At maturity the spore mother cells divide by meiotic divisions and form many haploid spores. More than species are funarua in the Netherlands.

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