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Funaria botany

1. The document describes the life cycle and morphology of the moss Funaria. It has a haplontic and diplontic life cycle with alternation of generations exhibiting heteromorphy. 2. The gametophyte generation is the dominant phase and reproduces sexually or asexually. Sexual reproduction involves antheridia and archegonia that produce gametes for fertilization. 3. Fertilization leads to formation of a sporophyte which grows from the archegonium. The sporophyte bears spores in capsules and releases them to complete the life cycle.

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Biological Life Cycles•
FUNARIA
SYSTEMATICPOSITION.. KINGDOM Plantae DIVISION Bryophyta CLASS Bryopsida SUB-CLASS Bryidae ORDER Funariales FAMILY Funariaceae GENUS Funaria
The genus is cosmopolitan in its distribution. It includes 117 species. F.hygrometrica is the most common moss which is found all over the world. The mosses grow luxuriantly in humus soil and on the soil burnt by fire. They grow well on damp rocks and wall. The green protonema grows on the newly ploughed fields while some are epiphytic and grows well on tree trunks. HabitAT and Distribution
The plant body is gametophytic and consists of two different stages : External structure of the gametophyte  Rhizoids arise from the base of the axis/ stem. They are slender, branched and multicellular and have oblique septa.  Axis/ stem are 1-3 cm high, upright, slender and branched. Each branch is extra axillary i.e. arise below a leaf.  Leaves are sessile, oblong-ovate with entire margin and pointed apex. Each leaf is traversed by a single mid rib. Leaves are borne in 1/3 phyllotaxy becomes 3/8 at maturity. 1. Juvenile stage represented by primary protonema. 2. The leafy gametophyte which is the adult form, differentiated into rhizoids, stem and leaves.
Internal Morphology o It is differentiated into epidermis, cortex and central cylinder. o Epidermis is single layered, cells contain chloroplasts in younger stages. At maturity, it is thick walled and without chloroplasts. Stomata are absent. o Cortex is multilayered and parenchymatous. o Central cylinder has thin walled, narrow and compactly arranged dead cells with non- lignified cells called as hydroids. ◦ Single celled in thickness in the wing region and multicellular in the midrib. ◦ Midrib has both upper epidermis and lower epidermis. ◦ A group of thin walled cells followed by a group of thick walled smaller cells with narrow lumen. ◦ The cells of the lamina and some outer cells of the midrib contain chloroplasts. ◦ Mesophyll and stomata are absent. Stem.. Leaf..
thallus
REPRODUCTI ON 2. By secondary protonema- When protonema is developed by other than the germination of the spore the it is called as sec. protonema. It may develop from any detached living part of the gametophyte. Vegetative reproduction- In moss the vegetative reproduction takes place by means of various methods : 1. By multiplication of primary protonema- In Funaria spores on germination form a branched, filamentous, multicellular structure. It is pr. protonema which certain colorless separations are formed by intercalary divisions. These cells die out and break up the protonema into many fragments. These fragments grows into new protonema containing buds which develops into leafy gametophytes.
3. By Gemmae- During unfavorable condition the terminal cells of the protonemal branches divide by transverse, longitudinal divisions and form green multicellular bodies of 10-30 cells. These are called gemmae. At maturity gemmae become slightly reddish brown in color. On the return of favorable conditions Gemma germinate and form new plant. 5. Apospory- Development of gametophyte from sporophyte without formation of spores is known as apospory. Any vegetative cell of the sporophyte may form green protonemal filaments which bears lateral buds later develop into leafy gametophyte. The gametophyte thus formed are diploid. Sexual reproduction in such gametophyte results in the formation of tetraploid (4n) zygote capable of bearing spores. 4. By Bulbils- When such gemmae like structures are produced on rhizoids inside the substratum these are called bulbils. They are devoid of chloroplasts but capable of developing them into leafy individuals under favorable conditions.
Sexual reproduction is oogamous. 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. Sexual reproduction
STRUCTURE OF ANTHERIDIA Club shaped and has a stalk and body. The stalk is short, slender, multicellular and biseriate. Body of the antheridium is multicellular and surrounded by a single layered jacket. 1 or 2 or more than 2 cells of the antheridial jacket of the distal end are larger and known as cover cells or lid cells or opercular cells. The cells present interior to jacket are called as androgonial cells. These cells divide and redivide and form androcyte mother cells.
STRUCTURE OF ARCHIGONIA ♦ It is flask shaped with a multicellular and multiseriate short stalk and broad body. ♦ Body has a basal swollen venter and a projected neck. ♦ Venter is surrounded by double layered jacket. ♦ Interior to it, it has a basal egg and above it a venter canal cell are present. ♦ Neck has a single layered jacket. Jacket has 6 vertical rows of cells. ♦ At the tip of the archegonium 4 cover cells arranged in diagonal pairs are present.
It takes place in the presence of water. The antherozoids move towards the archegonium in response to the sugars of archegonial secretion. This phenomenon is known as Chemotaxy. One of the male gametes that enter into the archegonial venter unites with the egg cell to form diploid zygote. Fertilization
Sporophyte (Sporogonium) (2n) ♠ It divides in the archegonial venter and forms multicellular embryo. It develops into sporophyte or sporogonium. ♠ It is partial parasite on gametophore. ♠ It reproduces asexually by producing spores. ♠ Due to fertilization stimulus, the jacket of archegonial venter divides and forms the protective structure known as Calyptra. ♠ During the growth of sporophyte, the calyptra is ruptured transversely and the upper part remains as a hood like structure over the capsule. ♠ Calyptra functions as a transpiring shield around the immature capsule. ♠ Developed sporophyte of Funaria is differentiated into Foot, Seta and Capsule.
1. Foot ¤ Basal sterile portion of sporophyte embedded in the female branch of gametophore. ¤ Absorbs water & minerals from gametophore and supplies them to the capsule through seta. 2. Seta ¤ Long, slender, reddish brown stalk like structure present between the foot and capsule. ¤ Helps in projecting the capsule out of the archegonial venter or calyptra. ¤ It conducts mineral water obtained from the foot to the capsule. ¤ It is hygroscopic, twists and curls during dry conditions and helps in scattering spores from the capsule. 3. Capsule ¤ It is the highly organized structure of sporophyte. ¤ It is pear shaped and green at the beginning. It later becomes dark brown when the calyptra falls off. ¤ It is involved in the production and dispersal of spores. ¤ It has 3 regions known as Apophysis, Theca and Operculum.
a) Apophysis  Solid, swollen, basal, sterile, green photosynthetic region of capsule.  It has single layered epidermis, multi-layered green photosynthetic tissue with prominent intercellular spaces (spongy parenchyma).  A conducting strand (Elongated thin walled colourless cells) present at the centre of the apophysis.  Conducting strand is continuous with the central strand of seta. b) Theca  Sporogenous cells divide and redivide mitotically and form spore mother cells.  These mother cells divide meiotically and form haploid spores in tetrad.  The 4 spores of a tetrad are separated from each other, rounded off and liberated individually.  Spore sac surrounds the central cylindrical parenchymatous compact region known as Columella. c) Operculum  It is obliquely placed cap-like structure present on the theca. It is also known as Lid.  It is separated from theca by two rings. The lower ring is rim or diaphragm and the upper one is known as Annulus.  Rim consists of 2 – 3 layers of special radially elongated thick-walled cells.  Annulus consists of 5 – 6 superimposed layers of cells. The upper cells are thick walled and small.
a. At maturity the lower tier of cells of annulus degenerate and the operculum proper is removed in the form of cap. This exposes the peristome. b. The thin walled cells of columella dry off. c. The capsule is inverted due to downward twisting of seta. d. In dry weather, the outer peristomal teeth loose water, curl, bend backwards and promote the easy liberation of spores. e. The jerking movements of peristomal teeth also aid in the removal of operculum. f. The inner peristomal teeth do not exhibit hygroscopic movements but act as a further check over the spore sac. g. The mechanical jerk of the capsule caused by twisting and untwisting of seta also aid in the dispersal of spores. Dehiscence of capsule..
i. Spore absorbs water and imbibes. Its exospore is ruptured and the inner endospore comes out as a tube like structure at one or both ends. ii. The germ tube elongates and forms protonema. Protonemal filaments on the substratum have transverse walls. These are known as chloronemal branches. iii. Some colorless branches that grow towards the soil have oblique cross walls and known as rhizoidal branches. These become green upon exposure to light. iv. After certain extent of development, buds are differentiated on the protonemal branches and later they develop into leafy gametophores. v. Differentiation of buds on the protonema is promoted by a type of cytokinin known as Bryokenin. Since several adventitious buds are developed on each protonema, gametophores grow and develop in tufts. vi. As the protonema dies, the gametophore becomes independent. Germination of spore
LIFE CYCLE… A. It is haplontic and diplontic life cycle. Both gametophyte and sporophyte are morphologically different. B. Hence the alternation of generations is heteromorphy.
THANK YOU!!! MANSI YADAV SECTION-C ROLL NO.-204