Plant Reproduction

• Fertilization


  The union of egg cell and sperm cell
• Asexual reproduction


  A mode of reproduction that does not involve the union of sex cells
• Pollination


  The placement of the pollen grain from the anther to the stigma of a carpel of a flower
• Reproduction


  A biological process in which an "offspring" is produced
• Sexual reproduction


  A mode of reproduction that involves the union of sex cells
• Reproduction is a biological process in which an "offspring" is produced from their "parent" or "parents"
• Importance of reproduction


  • Procreation
  • Variation
• Types of reproduction


  • Sexual reproduction
  • Asexual reproduction
• Sexual reproduction


  The production of offspring from the fusion of male and female gametes (two parents)
• Types of union of gametes

  • Isogamy - involves the male and female gametes of similar shape and size (morphology)
  • Heterogamy - male and female gametes of different shape and size (morphology)
• Asexual reproduction


  The production of offspring from one single parent and does not involve fusion of gametes
• Types of asexual reproduction

  • Binary fission - Separation of the body into two new bodies, common in single-celled organisms
  • Budding - A new individual arises as an outgrowth (bud) from its parent, develops organs like those of the parent, and then detaches itself
  • Fragmentation - The body breaks into two or more parts, with each fragment capable of becoming a complete individual
  • Sporulation - A new individual form from an aggregation of cells surrounded by a resistant capsule or spore, which later on germinates
  • Parthenogenesis - Female's egg develop into a new organism without being fertilized by a sperm cell, described as an "incomplete form of sexual reproduction"
• Advantages of sexual reproduction

  • Genetic diversity is maintained
  • Adaptation to changing environment is possible
• Advantages of asexual reproduction

  • Isolated/sessile species can perform it alone
  • Time efficient, can transpire without waiting for partner availability
  • Offspring can easily adapt to existing environment because of similarity in traits
• Disadvantages of sexual reproduction

  • Isolated/solitary/non-motile animals will not be successful
  • Some evolve to hermaphroditic characteristics (earthworm, tapeworm)
• Disadvantages of asexual reproduction

  • Genetic variation is limited to none at all
  • Adaptation will not ensure survival if environment drastically changes
• Since both sexual and asexual reproduction modes can promote offspring adaptation in the environment, which is a more advantageous mode to consider depends on the environmental situation
• Plant reproduction

  • Sexual reproduction
  • Vegetative reproduction
• Types of pollination

  • Self-pollination - transfer of pollen from the stamen to the stigma of the same flower
  • Cross-pollination - transfer of pollen in separate plants
• Pollinating agents

  • Animal-aided
  • Wind-aided
• Asexual reproduction in plants

  • Vegetative propagation - a plant part such as stems, leaves, roots or turions are used to reproduce new plants
  • Artificial vegetative propagation - needs human intervention
  • Natural vegetative propagation - no human interference
• Tubers


  Swollen portions of underground stems (stolons) with nodes and buds
• Rhizome


  An underground horizontal stem with stored foods and buds. Terminal and lateral buds give rise to new shoots.
• Runner


  Arises from the base of the stem as a lateral branch and runs along the surface of the soil
• Artificial methods of vegetative propagation

  • Cuttings - shoots that are removed from a plant and allowed to form new plants
  • Grafting - a section from one plant is attached to a section of another plant
  • Layering - a branch of a plant is fixed into the soil to allow it to form roots and a new plant
  • Micropropagation - the growth of new plants from tiny pieces of a parent plant
• Structure of a flower

  • Pedicel - the stalk that holds the flower
  • Peduncle
  • Receptacle - enlarged tip of the pedicel from which the floral parts arise
  • Sepal - leaf-like structures that protect the flower while it's still a bud
  • Calyx - collective term for all sepals
  • Petal - whorl inner to the sepals, may be brightly colored
  • Corolla - collective term for all petals
  • Perianth - collective term for sepals and petals
• Parts of the carpel/pistil

  • Stigma - sticky to trap pollen
  • Style - hollow tube that connects stigma and ovary
  • Ovary - produces female gametes (ovules)
  • Ovules - round or oval shaped inside the ovaries
  • Locule - cavity within the ovary
• Parts of the stamen

  • Anther
  • Filament
• Plant types based on the presence of reproductive structures

  • Monoecious - stamens and pistils occur on separate flowers, but same plant
  • Dioecious - staminate and pistillate flowers occur on separate plants
• Classification of flowers based on the presence of floral parts

  • Complete - a flower with sepals, petals, stamens and carpels
  • Incomplete - a flower that lacks one or more of the four essential floral parts
• Classification of flowers based on the presence of floral parts

  • Perfect/Bisexual - a flower that has both stamens and carpels
  • Imperfect/Unisexual - a flower that has only either the stamens (staminate flower) or the carpels (carpellate flower)
• Plant development

  • Gametophyte - production of the gametes (pollen grain and embryo sac)
  • Pollination - the transfer of pollen from an anther to a receptive stigma
  • Fertilization - one sperm and egg combine, forming a diploid zygote, the future embryo
  • Embryo development - ovules become the seed, ovary matures into the fruit, production of plant embryo from a zygote
  • Seed germination and growth - germination is the resumption of growth and development after a period of seed dormancy
• Double fertilization - one sperm fuses with the 2n polar nuclei, forming a triploid cell that will develop into the endosperm, which is the tissue that serves as a food reserve
• Gametophyte

  Production of the gametes (pollen grain and embryo sac)

  a.Male gametophyte

  b. Female gametophyte
• Male Gametophyte

  -Inside the anthers’ microsporangia, male gametophytes divide

  -by meiosis to generate haploid microspores which, in return, undergo mitosis and give rise to pollen grains.

  -Pollen grain contains two cells:

  -One generative cell and one pollen tube cell
• Female Gametophyte

  • The ovule inside the ovary contains the megasporangium.
  • Within each megasporangium, a megasporocyte undergoes meiosis, generating 4 megaspores: three small and one large.
• Pollination

  • Pollination- the transfer of pollen from an anther to a receptive stigma.
  • Agents- animals, wind, water, humans
• Fertilization

  • Fertilization- one sperm and egg combine, forming a diploid zygote, the future embryo.
  • Double Fertilization- other sperm fuses with the 2n polar nuclei, forming a triploid cell that will develop into the endosperm, which is the tissue that serves as a food reserve.
• Embryo Development

  • Production of plant embryo from a zygote
  • Ovules become the seed.
  • Ovary matures into the fruit.
• Seed germination and Growth

  • Germination is the resumption of growth and development after a period of seed dormancy.