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Plants (Angiosperm Reproduction (Pollination (Tube cell lengthens the…

- - - - Microspores develop into pollen grains which contain the male gametophyte
      - Formation
        
        microspore undergoes mitosis producing male gametophytes
        
        male gametophyte consists of: pollen grain (n), generative cell and tube cell
        
        microsporocyte undergoes meiosis and produces 4 microspores
        
        Generative cell divides producing 2 sperm cells
    - - megaspores develop into embryo sacs (female gametophyte) within the carpels
      - Formation
        
        Megasporocyte undergoes meiosis and produces 4 megaspores
        
        One megaspore survives and becomes female gametophyte
        
        embryo sac consists of: antipodal cells, polar nuclei, Synergids and egg (haploid)
  - - - Union of two sperm cells with different nuclei of female gametophyte
- - - - vascular cambium
        
        adds layers of vascular tissue (secondary xylem and phloem)
      - cork cambium
        
        replaces epidermis with periderm
  - - - plant growth happens at meristem: tissue that remains embryonic, allowing for continual growth
      - Apical Meristems
        
        occurs in all plants
        
        located at the tips of the stem and roots
      - Lateral Meristems
        
        occurs only in woody plants
        
        promotes growth in thickness
- - - - act of placing pollen on the stigma of a carpel
    - - self-fertilization
        
        seen in crop plants
        
        pro: ensures that every ovule develops into a seed
        
        the plant combines its own pollen and ovule to form a zygote
        
        con: decreases genetic diversity
        
        some plants have developed mechanisms to prevent this from happening (carpel and stamen located differently, they mature at different times or self-incompatibility)
      - abiotic fertilization
        
        wind carries pollen to another plant
      - biotic fertilization
        
        animals carry the pollen
        
        bats
        
        insects (bees, moths, butterflies, flies)
        
        birds
  - - - Generation of offspring from a single parent that occurs without the fusion of gametes
      - offspring are genetically identical to their parent
      - also called vegetative reproduction
    - - Division of the entire organism
      - Division of a single cell
      - Budding
    - - Fragmentation
        
        Detached fragment of plant that can develop into a whole (new) plant
      - Apomixis
        
        plants that can produce seeds without pollination or fertilizatio
    - - offspring are not spread out
      - offspring must be able to survive in the current environment, if not they will die
      - less genetic diversity
    - - No need for pollinator
      - Offspring have desirable genes
      - stronger progeny, skips the weak seedling stage
      - does no require as many resources from parent
  - - - female gametophyte
    - - male gametophyte
- - - - Structure
        
        connects to the stem at a node
        
        consists of a flattened blade and petiole (stalk)
        
        vascular tissue: veins of the leaves that transports the supplies and products of photosynthesis
        
        physical structure varies substantially between species of plants
      - Tissues
        
        Mesophyll
        
        cells specialized for photosynthesis
        
        Stomata
        
        pores in the leaf that allows for gas exchange
        
        Guard Cells
        
        opens and closes stomata to regulate water loss
        
        Vascular Tissue
        
        transports nutrients and photosynthesis products
      - Main photosynthetic organ
        
        responsible for
        
        gas exchange
        
        heat dissipation
        
        photosynthesis
        
        defense against pathogens and herbivores
    - - The main mass of the plant
      - Leaves are attached and the stem grows to elongate and orient the leaves to maximize photosynthesis as well as reproductive functions
      - Parts
        
        Nodes: point where the leaves attach
        
        Internodes: segment between nodes
      - Growth
        
        Apical Bud
        
        Bud at the tip of the stem, promotes vertical growth
        
        Axillary Bud
        
        bud on the side of the stem which promotes lateral growth to form branches
    - - Anchors the plant to the soil and absorbs nutrients (mineral and water) and can store carbohydrates
      - SystemTypes
        
        Fibrous Root
        
        consists of a bunch of small thin roots that are just below the surface, generation point is the base of the stem
        
        Taproot
        
        consists of one main root that penetrates deep into the soil and acts as a structural stabilizer to keep plant upright, allowing plant to grow tall
        
        lateral roots branch off main root and are used for absorption
      - Adaptations
        
        Root Hairs
        
        increases the surface area of the roots with finger-like extensions which increases efficiency of absorption
        
        Mycorrhizal relationships
        
        symbiotic relationship with fungus which improves ability to absorb nutrients
        
        Adventitious
        
        plant will grow in an unusual location because where the roots take hold
  - - - Used for transporting materials throughout the plant
      - used for mechanical support of the plant
      - Types
        
        Xylem: transports mainly water with some dissolved minerals from the root system to the shoot system
        
        Phloem: transports sugars to the roots and growth sites
      - Stele
        
        Vascular Cylinder
        
        Located in the roots, a solid central bundle of vascular tissue
        
        Vascular Bundle
        
        found in the stem and leaves, separate stands of vascular tissues
    - - Tissues that are neither dermal or vascular
      - Types
        
        Pith
        
        Internal to vascular tissue
        
        Cortex
        
        External to the vascular tissue
      - Note: not filler, provide some function for photosynthesis, short distance transport, storage and support
    - - Protective outer covering, protects against pathogens and physical damage
      - Non-woody plants: consists of epidermis - tightly packed cells and cuticles - waxy coating to prevent waterloss
      - Woody plants: periderm - harder outer coating (bark) that offers more protection than the epidermis, mainly found in the older stem and root sections.