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Showing posts from January, 2020

Vegetative Reproduction by Stem

Vegetative Reproduction by Stem a. By Rhizome: These are Stem-like structures that’s grows horizontally across the ground and from which new roots and shoots may arise. They serve as protein and starch storage units serving as a nutrient source for newly developed plants. b. By Stems : In this process, new plants arise from the nodes. This is where buds are formed, which grow into new plants. Stems that grow horizontally on the ground are called runners . As these runners grow, bud formation at the nodes, which later develop the roots and shoots, resulting in the formation of new plant. E.g . Cyanadon , Mint etc. In the plant’s potatoes, stem tubers are found. This part is the swollen apical part containing many nodes or eyes. Every eye has buds. New plants originate from these buds.

Vegetative Reproduction by Roots

Natural Vegetative Propagation Natural vegetative propagation occurs when an axillary bud grows into a lateral shoot and develops its own roots (also known as adventitious roots). Plant structures allowing natural vegetative propagation include bulbs, rhizomes , stolons and tubers . Natural Reproduction done by following methods: a. By Roots : In this process, new plants grow out of the modified roots called tubers . Some plant roots also develop adventitious buds. These buds grow and form new plants/sprouts under the right conditions. These sprouts can be separated from the parent plant and when planted in other areas, new plants are formed. E.g . Sweet potato, Dahlia etc.

Vegetative Reproduction, Vegetative Propagation or Vegetative Multiplication

Vegetative Reproduction Ø Vegetative reproduction (also known as Vegetative Propagation, vegetative multiplication or cloning ). Ø It is a form of asexual reproduction, occurring in plants in which a new plant grows and form a fragment of the parent plant or a specialized reproductive structure. Ø Vegetative propagation is following two types on the basis of growing process: 1. Natural Vegetative Propagation 2. Artificial Vegetative Propagation

Reproduction by Zoospores

Reproduction by Zoospores o Members of Kingdom Fungi & algae reproduce through special reproductive structures called zoospores in aquatic medium. o These are flagellated, motile, naked protoplasmic bodies. o Zoospores are produced in Zoosporangium . o Zoospores are may be biflagellate (Chlamydomonas and Ectocarpus), Quadriflagellate (Ulothrix) or Multiflagellate (Oedogonium). o Multinucleated Zoospores are known as Synzoospores.

Reproduction By Conidia

Reproduction by Conidia: o These are non-motile spores produced endogenously by constriction at the tips of special hyphal branches known as conidiophores . o Asexual reproduction in ascomycetes (the phylum Ascomycota ) is the formation of conidia, which are borne on specialized stalks called conidiophores . o The morphology of these specialized conidiophores is often distinctive between species and, before the development of molecular techniques at the end of the 20 th century, was widely used for identification of (e.g. Metarhizium ) species.

Reproduction by Gemmule. Gemmulation.

Reproduction by Gemmule (Gemmulation) o The internal buds, which are formed by the freshwater sponges are called as gemmules are touch and coated with a dormant cluster of embryonic cells. o Freshwater sponges are multi-cellular, marine living species of a Kingdom Phylum- Porifera . o Gemmules are usually found in a round ball like structure, along with a central mass of amoeboid cells and a thick peripheral layer of a small siliceous spicule.

Asexual Reproduction by Regeneration

Regeneration (Re=again, Generate=grow) o Regeneration is asexual reproduction is the ability of a simple organism to re-grow its lost parts. o Simple organisms are more successful with regeneration than complex organisms. E.g. Some crabs can grow new claws or body parts after the original parts are lost. o Every species is capable of regeneration from bacteria to humans .

Asexual Reproduction by Fregment in Planaria, Hydra and Starfish

Fragmentation (Fragment=small pieces) o Fragmentation in multi cellular organisms is a form of asexual reproduction in which an organism is split into fragments and develop into matured, fully grown individuals that are identical to their parents. o In this type of reproduction parent cell divides into fragments and each fragment becomes a new individual. o Fragmentation, also known as splitting, as a method of reproduction is seen in many organisms such as filamentous Cyanobacteria, molds, lichens, many plants, and animals such as sponges, acoel flatworms , some annelids worms and sea stars .

asexual reproduction by spores in Rhizopus

Sporulation (Reproduction by Spores) o It is a type of asexual reproduction in which non flowering plants such as fungi ( Rhizopus ) and bacteria produces offspring by spore formation. o In this reproduction parent plant produces hundreds of tiny spores which can grow into new plants. o Each spore produces a new plant.

Budding reproduction

A. Budding (Bud=Outgrowth) o Budding is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. o It is most commonly associated in both unicellular and multi-cellular organisms. o Bacteria, yeast, corals, flatworm, jellyfish and sea anemones are some animal species which reproduce through budding. Mechanism: Each Bud or Outgrowth arise at any plane of parent body enlarges, develops the independent life. It feeds, grows, becomes an adult and repeats the process. a. Unicellular organism (Yeast) b. Multicellular organism (Hydra) a. In Unicellular organism: o The small bud-like projection coming out from the yeast cell is called a bud . A small bud arises as an outgrowth of the parent cell. o Later the nucleus is separated into two parts and one of the nuclei shifts into the bud. The newly created bud divides and grows into a new cell.

Multiple Fission

Multiple fission (Multi=many, fission=division) Definition : it is type of asexual reproduction in which the parental body divides into many daughter cells simultaneously during the unfavorable condition to increase the chances of survival of daughter cells. Occurrence: Multiple Fission is found in a number of organisms e.g. algae among plants, Plasmodium Malarial parasite, Amoeba, Monocystis . Mechanism: o Multiple fission occurs when condition not favorable. o Under unfavorable condition mother cell produce a layer called “ cyst ” ( encystation ) and nucleus of parent cell divides by repeated amitosis many times and produce many daughter nuclei this process is called “ karyokinesis ” then followed by division of cytoplasm ( cytokinesis ). o When favorable condition comes this cyst ruptured, daughter cells comes out and form individual organism. o Some cytoplasm of the parental body remains unused

what is Binary Fission? How many types of Binary Fission?

Asexual reproductions are following types: A. Fission B. Budding C. Spore formation D. Fragmentation E. Regeneration F. Gemmulation G. Conidia formation H. Zoospores I. Vegetative propagation A. Fission (Fission=division) It is type of Asexual reproduction in which a fully-grown parent cell divides into two or more than two daughter cells. In this, the reproductive unit is whole parental body. Types of Fission: On the basis of number of off-springs produced, fission reproduction is divides into two categories: (a) Binary Fissio n Definition: I t is division of adult parental body into two nearly equal daughter cells during favorable condition. Occurrence: It is the simplest and most common method of asexual reproduction found in protists (Amoeba, Euglena, Paramecium), bacteria, green algal forms (Chlamydomonas) and planarians (flat worms). Mechanism: In binary fission, nucle

Types of Reproduction

Types of Reproduction There are two forms of reproduction: Asexual and Sexual. 1. Asexual Reproduction 2. Sexual Reproduction 1. Asexual Reproduction Definition: Asexual reproduction or apomixis is the formation of new individuals without involving the formation and fusion of gametes. Or Asexual reproduction by which offspring arise from a single organism, and inherit the genes of that parent only: it does not involve the fusion of gametes, and almost never changes the number of chromosomes. In this type of reproduction offspring are identical to their parents. Characteristics i. In asexual reproduction, only one parent is involved, so called uniparental (monoparental) reproduction. ii. It does not involve formation and fusion of gametes. iii. It involves mitotic divisions. iv. It involves rapid reprod

What is Reproduction?

Reproduction in organisms Re= again, Production=formation/produce What is Reproduction? Reproduction is the biological process by which new individual organisms – “offspring” – are produced from their “parents” . Or The creation by a life form of a similar life form is called reproduction. Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction. Why do organisms reproduce? Organisms are reproduced for the continuity of life. Every organism has a fixed time period from birth to natural death is called “ Life Span ”.

What is biology?

Biology ( Bio=life , logy=study ) Study of living being is known as biology . Aristotle first study living organisms are known as " Father of Biology. " Aristotle also known as "Father of Botany." Biology is a branch of science in which deals or study of living organisms.