Plant Reproduction Introduction PDF

Classification of Plants Jo-Ann R. Engaño, MSc. Classification of Plants The most important and most commonly used methods of classifying plants is the botanical method which is based on descent or phylogenetic relationship of plants. Classification of Plants Phylogen...

Classification of Plants Jo-Ann R. Engaño, MSc. Classification of Plants The most important and most commonly used methods of classifying plants is the botanical method which is based on descent or phylogenetic relationship of plants. Classification of Plants Phylogenetic classification systems based on evolutionary relationships between the various organisms ae acceptable. This assumes that organisms belonging to the same taxa have a common ancestor There are approximately 3,000,000 plants species identified and classified into 4 main divisions in the plant kingdom as follows: 1.)THALLOPHYTES 2.) BRYOPHYTES 3.) PTERIDOPHYTES 4.) SPERMATOPHYTES  Plant Kingdom Bryophytes Spermatocytes Pteridophytes Thallophytes Algae Fungi Bacteria  Thallophyte Thallo = plant body without root, stem, and leaves. Phyta = a plant Any of very many primitive plants that consists of a thallus formerly collected in the obsolete(no longer produced or used) taxonomic group Thallophyta.  Thallophyte The thallophytes are a polyphyletic (many races) group of non- mobile organisms traditionally described as thalloid plants, relatively simple plants or lower plants. Thallophytes are mainly aquatic plants. Example are algae, fungi, lichens and bacteria, plant from the phylum(Division) of thallophyta.  Thallophyte The plant body may be unicellular or colonial or multicellular in organization. The sex organ are unicellular. Thallophytes reproduction is mainly asexual. The thallophytes are defined as having undifferentiated bodies (thalli). They have a hidden reproductive system and hence they are also called Cryptogamae.  Thallophyte Thallopytes are further divided into following groups. Algae Fungi Bacteria Lichens  Algae (singular: Alga) means seaweeds Algae are pond scums, terrestrial algae, snow algae, seaweeds, freshwater and marine phytoplankton. The plant body is relatively undifferentiated, and there are no true roots and leaves. The "green algae" is the most ✓ They possess the green pigment diverse group of algae, called chlorophyll. With this pigment, which absorbs the radiant energy of more than 7000 species the sun, they can manufacture food by growing in a variety of habitats. the process of photosynthesis. Algae Unicellular (single-cell) ▪ Reserve Food: In the form of A single-cell organism starch Colonial ▪ Most of the member have Single-cell organism coming storage bodies called together pyrenoids located in the chloroplasts. Pyrenoids Multicellular contain protein. Filamentous (thread) branched or unbranched complex Some algae store some food in the form of oil droplets. Algae have 3 methods of Reproduction ❑ Vegetative reproduction ❑ Asexual Reproduction ❑ Sexual Reproduction -The Thallus divides into smaller fragments and each part later on gives arise to a new plant. -This process is termed fragmentation Algae have 3 methods of Reproduction ❑ Vegetative reproduction ❑ Asexual Reproduction ❑ Sexual Reproduction Take place by means of spores called zoospores produced in zoosporangia. They are associated 2 or 4 whip like flagella (to whip) of equal length. Algae have 3 methods of Reproduction ❑ Vegetative reproduction ❑ Asexual Reproduction ❑ Sexual Reproduction Isogamy is a form of sexual reproduction that involves gametes of similar morphology (similar shape and size). Because both gametes look alike, they cannot be classified as "male" or "female“, most commonly noted as "+" and "−" strains Fertilization occurs when gametes of two different mating types fuse to form a zygote(to join). Like the plants, the green algae contain two forms of chlorophyll(a&b), which they use to capture light energy to fuel the manufacture of sugars, but unlike plants they are primarily aquatic. Because they are aquatic and manufacture their own food, these organisms are called "algae,“ Groups of algae Phyla Cell wall Brown Algae Phaeophyta Cellulose, algin Red algae Rhodophyta Cellulose, agar Green algae Chlorophyta Cellulose Dinoflagettes Dinoflagellata Cellulose Diatoms Bacillariophyta Prectin, Silica Water molds Oomycota Cellulose A fungus ( plural: fungi or funguses ) is any member of the group of eukaryotic organisms that includes unicellular microorganisms such as yeasts and molds. multicellular fungi that produce familiar fruiting forms known as mushrooms. Plant diseases caused by fungi include rusts, smuts, and leaf, root, and stem rots, and may cause severe damage to crops. Characteristics Eukaryotic Heterotrophs Cell wall – chitin Filamentous - hyphae No tissue Reproduction in fungi Can be Asexual or Sexual Fungi can reproduce asexually by fragmentation, budding, or producing spores. New colonies of fungi can grow from the fragmentation of hyphae. Asexual spores are genetically identical to the parent and may be released either outside or within a special reproductive sac called a sporangium. Ascomycota - Sac fungi - Antibiotics Basidiomycota - Club fungi - Mushrooms Chytridiomycota - Flagellated - “protists”  Glomeromycota - Plant symbiosis - mycorrphiza (with the roots or thalli)  Zygomycota - Sporangia - Bread mold  Bacteria ( singular: bacterium ) Bacteria have a number of shapes, ranging from spheres to rods and spirals. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. Bacteria also live in symbiotic and parasitic relationships with plants and animals - Nucleoid region Bacteria are single-celled microorganisms, - Plasmids generally ranging from - Capsule 1-2 µm in size that cannot be seen with the unaided - Pilus (plura: Pili) eye. - Cell Wall: peptidoglycan Pili or pilus How they Reproduce Bacteria are prokaryotic organisms that reproduce asexually. Bacterial reproduction most commonly occurs by a kind of cell division called binary fission. Binary fission results in the formation of two bacterial cells that are genetically identical.  A lichen is a composite organism that arises from algae or cyanobacteria (or Lichens both) living among filaments of a fungus in a symbiotic relationship. Lichens come in many colors, sizes, and forms but lichens are not plants Lichens do not have roots that absorb water and nutrients as plants do but like plants, they produce their own food by photosynthesis using sunlight energy, from carbon dioxide, water and minerals in their environment. When they grow on plants, they do not live as parasites and only use the plants as a substrate(underlies). Lichens are really combinations of species from two or three different biological kingdoms. So there is no common lineage. Lichens have the same scientific name as the fungus in them, and are not classified according to the species of the algae and or cyanobacteria growing in them.  Types of Lichens Fruticose - Lichens may have tiny, leafless branches Foliose - flat leaf-like structures Crustose - flakes that lie on the surface like peeling paint Lichen Growth Forms Crustose (crusty) edges flat, unlobed and closely Foliose (leafy) attached to substrate A sandwich of fungal layer with algal hard to remove without damaging mat in middle substrate or lichen circular growth, lobes algae usually dispersed small rootlets called rhizines attach it to edges unlobed (leprose and squamulose substrate included here) top and bottom layers different Fructicose (shrubby) round branches with its fungal layer outside, its algal layer within no rhizines vertical growth pattern odd-shaped structures such as globets; threads Fruticose lichens are either shrub-like small mounds, growing up from the ground, or beard-like, small tangles looking a bit like spanish moss when hanging down, attached to the substrate only at their bases, and usually with a circular cross-section. How lichens are formed? A particular fungus species and algal species are not necessarily always associated together in a lichen. One fungus, for example, can form lichens with a variety of different algae. Many lichens reproduce asexually, either by vegetative reproduction or through the dispersal of diaspores containing algal and fungal cells. Soredia (singular soredium) are small groups of algal cells surrounded by fungal filaments that form in structures called soralia, from which the soredia can be dispersed by wind.  Plant Kingdom Thallophytes Bryophytes Spermatocytes Pteridophytes Gymnosperms Angiosperms  Spermatocytes All seed-bearing plants which are in turn divided into two subdivision: A.) Gymnosperms- include all plants with naked seeds like pines trees. B.) Angiosperms- seeds enclosed in a vessel and are in turn divided into 2 classes; I. Monocotyledon – one cotyledon II. Dicotyledons – two cotolydons Gymosperms  Gymosperms Needle-shaped leaves Male cones Female cones (in clusters) (scattered) Gymosperms Gymosperms the plants that are most ancient vascular, flowerless, seed-producing, and can reproduce through an exposed seed or ovule. Characteristics of Gymnosperms tall evergreen trees roots, woody stems needle-shaped leaves cones with reproductive structures naked seeds in female cones. As gymnosperm lacks an ovary, it can’t produce fruit. Angiosperms the plants that are most ancient vascular, flowerless, seed-producing, and can reproduce through an exposed seed or ovule. Characteristics of Angiosperms Highly developed Flowering plants Seeds inside ovary 2 types: 1. MONOCOTYLEDONS 2. DICOTYLEDONS Monocotyledons Dicotyledons One seed-leaf Two seed-leaf Leaves have parallel veins Leaves have veins in network Herbaceous plants e.g. trees, sunflower, rose e.g. grass, maize  Plant Kingdom Spermatocytes Pteridophytes Thallophytes Bryophytes Moss Liverworts  Bryophytes ▪ Include the various mosses and liverworts that are found commonly growing in moist shaded areas in the hills. ▪ Bryophytes are also called “amphibians of the plant kingdom” - they can survive in soil but are dependent on water for sexual reproduction.  Bryophytes Produces gametes, hence is called a gametophyte. The sex organs in bryophytes are multicellular. Male sex organ – antheridium, produces biflagellateantherozoids. Female sex organ – archegonium, flask-shaped and produces a single egg. Spore-producing capsule Moss  Characteristics of Moss Simplest plants No true roots, No vascular tissues (no transport) Simple stems & leaves Have rhizoids for anchorage Spores from capsules (wind-dispersal) Damp terrestrial land  Characteristics of Moss Vegetative reproduction is asexual by fragmentation and budding in the secondary protonema Characteristics of Liverworts Grow in moist, shady habitats Asexual reproduction takes place by fragmentation of thalli, or by the formation of specialized structures called gemmae Characteristics of Liverworts Grow in moist, shady habitats Asexual reproduction takes place by fragmentation of thalli, or by the formation of specialized structures called gemmae Plant Reproduction What is Plant Reproduction the production of one's own kind. It is necessary for the continuation of the species on earth and also to replace the dead members of the species. The process by which living organisms produce their offspring for the continuity of the species is called reproduction. All organisms pass on their hereditary material to their offspring during the process of reproduction. Types of Plant Reproductions 1. Asexual Reproduction ❖No gametes ❖Only one parent needed ❖New organism genetically identical to parent ❖Plants and bacteria reproduce this way  Asexual Reproduction Types 1. Fission As in unicellular organisms like bacteria where the content of the parent cell divides into 2, 4 or 8 daughter cells and accordingly the fission is known as binary or multiple fission. Each newly formed daughter cell grows into a new organism.  Asexual Reproduction Types 2. Budding A bud like outgrowth is formed on one side of the parent cell and soon it separates and grows into a new individual e.g. in yeast.  Asexual Reproduction Types 3. Fragmentation In filamentous algae, an accidental breaking of the filament into many fragments, each fragment may give rise to a new filament of the algae by cell division e.g. Spirogyra, green algae.  Asexual Reproduction Types 4. Spore Formation In lower plants like bryophytes reproductive units develop asexually on the parent body. These are called spores. They are microscopic and covered by protective wall. When they reach the suitable environment they develop into a new plant body e.g. in bread moulds, moss, fern. Types of Plant Reproductions 2. Sexual Reproduction ❖Male and Female Gametes involved ❖Two parents needed ❖New organism will not be genetically identical to either of the parent Reproduction in Angiosperms reproduction occurs by fusion of male and female gametes present in the flower. Angiosperms can be classified depending the time they take to complete life cycle and flowering Reproduction in Angiosperms Angiosperms (flowering plants) Plants that protect their seeds within the body of a fruit. Make up ¾’s of all plants, including: – Trees, shrubs, herbs, grasses, water plants… Reproduction in Angiosperms Angiosperms (flowering plants) Plants that protect their seeds within the body of a fruit. Make up ¾’s of all plants, including: – Trees, shrubs, herbs, grasses, water plants… Reproduction in Angiosperms Angiosperms can be classified depending the time they take to complete life cycle and flowering: Annuals - Live for one year, produce flowers and seeds within one season. Example: African Daisy Reproduction in Angiosperms Angiosperms can be classified depending the time they take to complete life cycle and flowering: Biennials - two seasons, first year vegetative state, second year produce flowers, fruits and seeds Example: Reproduction in Angiosperms Angiosperms can be classified depending the time they take to complete life cycle and flowering: Perennials - plants which live for several years , one to few years vegetative stage then after that flowers, fruits and seeds every year Example: Reproduction in Angiosperms Angiosperms can be classified depending the time they take to complete life cycle and flowering: Monocarpic - plants are those that flower, set seeds and then die Example: Agave plants The Flower The flower is the part of a plant that is involved in sexual reproduction The Parts of the Flower Sepals Petals Carpel Stamen Stages in Sexual Reproduction in Plants: ▪Pollination ▪Fertilisation and Seed Formation ▪Seed Dispersal ▪Germination  Welcome To Presentation I'm Rain, and I'll be sharing with you my beautiful ideas. Follow me at @reallygreatsite to learn more. Plant Reproduction Pollination ▪ Happens when pollen from one flower is transferred to another flower of the same species ▪ Insect Pollination(Entomophily) or Wind Pollination (Anemophily) Plant Reproduction Two Types of Pollination Self pollination – transfer of pollen grains to stigma of same or another flower of same plant Cross pollination – transfer of pollen grains to stigma of a flower of another plant of the same species  Plant Reproduction Insect Pollination: ▪ Petals are bright and perfumed. ▪ Insect rub against Anther and pollen gets stuck to them. ▪ Insect move to another plant of same species and pollen sticks to sticky stigma  Plant Reproduction Wind Pollination: ▪ The flowers have long anthers which hang outside the flower. ▪ Pollen is blown out of the anthers by the wind ▪ The stigma of a wind-pollinated flower is very large and feathery – able to catch pollen  Plant Reproduction Fertilisation and Seed Formation: ▪ After pollination, pollen tube develops out of the pollen grain and into the style, ▪ It then enters the ovule and male gamete travels down to join with the egg – zygote ▪ The zygote then becomes the seed. ▪ The ovary will turn into the fruit Dispersal of the Seed The major function of the fruit is to scatter the seed of the plant. Dispersal of the Seed Wind Dispersal The wind provides a very effective method of carrying fruit away from the parent plant. Dandelion uses parachute Mahogany tree uses winged seeds Dispersal of the Seed Animal Dispersal Edible Fruits: Animal eats fruit and eventually passes the seed in its droppings, if seed falls in right place it will grow into new plant. Hooked Fruits: Fruits have tiny hooks on their surface, sticks to the animals. Dispersal of the Seed Water Dispersal Water currents carry the fruit away, with the seeds inside. Ex. The water lily fruits can float. Dispersal of the Seed Self Dispersal In summer the plant dries out and suddenly bursts. The seeds shoot out from the fruit, and may land some distance from the parent plant