Plant Reproduction PDF

# Plant Reproduction ## Asexual Reproduction * Species: Simple species, prokaryotes + some eukaryotes * Members: One * Reproductive cells: No special cells (except spore reproduction) * Genetic diversity: No fusion cells, no genetic recombination * Type of population: Homogenous (clone) to parents...

# Plant Reproduction ## Asexual Reproduction * Species: Simple species, prokaryotes + some eukaryotes * Members: One * Reproductive cells: No special cells (except spore reproduction) * Genetic diversity: No fusion cells, no genetic recombination * Type of population: Homogenous (clone) to parents * Number of offspring: Exponentially * Stages (process): In Chapter 1 ## Sexual Reproduction * Species: Complex species, "most" eukaryotes * Members: 2 different but same species * Reproductive cells: Male & female gametes * Genetic diversity: Present due to genetic recombination * Type of population: Heterogeneous, different than parents * Number of offspring: Less in number * Stages (process): * Meiosis → reduces gametes to half * Fertilization → union of gametes ## Plants May Combine Reproduction According To Environmental Conditions * Asexual (favorable conditions) * Sexual (unfavorable conditions) ## Chapter 1: Reproduction of Prokaryotes (Monera) Prokaryotes reproduce by: * Binary fission (scissiparity) * Budding * Formation of endospores ### Processes * **Replication**: Number of poles → Cross wall formed → Splitting * **Duplication of chromosome**: Form bud → Have cytoplasm + plasma membrane → Division * **By unfavorable conditions, endospores resist these factors**: Killed by high pressure & high temperature * **Duplication of chromosome**: Poles (not equal) → Spore septum surrounds the DNA ## Asexual Reproduction of Cyanobacteria (Cyanobacteria = Eubacteria, photosynthetic bacteria, also known as blue-green algae) * **Fission**: Replication + splitting * **Fragmentation**: Separating fragments, then regeneration * **Hormogonia**: (Motile) reproduction by fragmentation for spots that were proreproducer, then regeneration of these pieces (Hormogonia) * **Separation disc**: (surrounded by a mucilaginous sheath) forms Hormogonia → then they separate to glide and form new filaments * **Heterocyst**: Filamentous → fixes nitrogen * **Heterocyst regeneration**: fragmentation → each one forms a new one * **Akinetes**: Under unfavorable conditions → store essential materials → when conditions become favorable, the akinete germinates into its normal (vegetative) form ## Chapter 2: Sexual Reproduction ### Syngamy Process * Plasmogamy + karyogamy * Result: Formation of zygote ### Dikaryon * Not a zygote → It's when the nuclei divide but not the cytoplasm * Example: Fungi ## Types Of Sexual Reproduction (Morphology-Based) ### Isogamy * Equal morphology * Example: Chlamydomonas ### Anisogamy/Heterogamy * Different morphology * Female > Male gametes * Example: Ulva ### Planogamy (Zogamy) * Motile gametes * Can be isogamy ### Aplanogamy * Non-motile gametes * Example: Red algae ### Oogamy * Large, non-motile female gamete + small, motile male gamete * Example: Fucus ## According To Mode Of Fertilization ### Somatogamy * Plasmogamy but delayed Karyogamy * Example: Basidiomycota ### Conjugation / Cystogamy * Involves a donor (ơ) and a recipient (♀) * The donor gives its genetic material through a tube called a conjugation tube or protuberance ### Trichogamy * The female has a hair-like structure called Trichogyne, which attaches sperm, sperm then fuses to the female nucleus * Example: Red algae ### Siphonogamy * Non-motile sperm is conducted to the egg via a tube * Example: Angiosperms ## Life Cycle * All cycles include meiosis and fertilization * Meiosis → Mitosis → Gametophyte (n) → Sporophyte ## Types Of Cycles ### Monobiontic Or Monogenic (One Generation) #### Haplontic Cycle * Single generation, cells are haploid * Absence of sporophyte * Only zygotes are diploid * Mature organism = Gametophyte (n) * **Process**: * Fertilization → Zygote (2n) * Meiosis → (n) * Mitosis → Gametophyte * Produces gametes #### Diplontic Cycle * Single generation, cells are diploid * Presence of sporophyte * Gametes are the only haploid cells * Mature organism = Sporophyte (2n) * **Process**: * Fertilization → Zygote (2n) * Mitosis → Sporophyte * Meiosis → Production of gametes ### Haplodiplontic Or Digenic Life Cycle **Steps**: * Fertilization → Zygote (2n) * Zygote → Mitosis → Sporophyte (2n) * Meiosis → Spores (n) * Spores (n) → Mitosis → Gametophyte (n) * Gametophyte (n) → Mitosis → Gametes (n) ### Triplobiontic Or Trigenic Life Cycle * Produces three generations: * Gametophyte (haploid) (n) * Carposporophyte (diploid) (2n) * Tetrasporophyte (diploid) (2n) ## Chapter 3: Reproduction of Algae (Protists) ### I. Asexual Reproduction * Mitosis → Fragmentation, Budding, or Spore Formation ### II. Sexual Reproduction #### 1. Monobiontic Haplontic - Spirogyra (n) * Filamentous algae found in freshwater * **Mode of Fertilization**: Conjugation * **Process**: * Formation of protuberance → Forms conjugation tube * Male cells move to fuse with the female protoplast * Forms zygospore → Ruptures → Releases zygospore * Zygospore enters dormant stage * In favorable conditions, it undergoes meiosis to produce spores (n) * Spores (n) undergo mitosis → Forms Gametophyte (n) * New Spirogyra is formed #### b. Monobiontic Diplontic - Fucus (2n) * **Type**: Brown Algae, found in marine water * **Mode of Fertilization**: Oogamy * **Structure**: * Branched Thallus in Sporophyte (2n) * Conceptacles (contain gametangium) * Receptacles with paraphyses * Male & female conceptacles on separate thallus * **Reproduction Process**: * Female (Oogonia): Meiosis produces nonmotile eggs (n) * Male (Antheridia): Meiosis produces biflagellated sperm (n) * Egg & sperm are released in water * Egg releases pheromones → Attracts sperm (Chemotaxis) * Fertilization occurs externally in water * Fertilized egg settles * Zygote (2n) undergoes mitosis → Forms Diploid Sporophyte #### 2a. Isomorphic Haplodiplontic - Ulva * Ulva species have: * Haploid Gametophytes (n) * Diploid Sporophyte (2n) * **Gametes**: * Female gamete: Large, biflagellated, motile * Male gamete: Small, biflagellated, motile * **Type of fertilization**: Planogamy & Anisogamous * **Reproduction Process**: * Fusion of gametes → Produces quadriflagellate zygote * Zygote swims, then rests, eliminates flagella & grows into sporophyte * Sporophyte undergoes meiosis → Produces quadriflagellate zoospores * Zoospores eliminate flagella & develop into gametophytes #### b. Heteromorphic Haplodiplontic – Laminaria * **Heteromorphic**: Different morphology of sporophyte & gametophyte * **Fertilization Type**: Oogamy * **Characteristics**: * Large sporophyte & microscopic male & female gametophytes * On the surface blade of sporophyte: * Sporangia grouped into sori * Paraphyses = Sterile cells * **Fertilization Process**: * Female & male gametes are flagellated * Zygote becomes sporophyte via mitosis * Sporangia (on sporophyte) undergo meiosis * Production of flagellated zoospores