bio

• PLANTS are among the most successful organisms on the planet
• The ability of plants to alter between reproduction and development allowed to colonize environments with diverse conditions
• PLANTS have also evolved various reproductive structures to allow them to increase their chances of successful fertilization and development
• Non-Vascular Plant


  • lignified vascular tissues absent
• Vascular Plant


  • lignified vascular tissues present
• PLANT CHARACTERISTICS


  • Multicellular organisms
  • Photosynthetic capacity
  • Cellulosic cell wall
  • Plastid in cytoplasm
  • Life cycle with alternation of generation
• MAJOR PLANT GROUPS


  • BRYOPHYTES
  • PTERIDOPHYTES
  • SPERMATOPHYTES
• BRYOPHYTES


  • Spore-bearing non-vascular plants
  • hornworts, mosses, liverworts
• PTERIDOPHYTES


  • Spore-bearing vascular plants
  • Ferns, Horsetails, lycophytes
• SPERMATOPHYTES


  • Gymnosperms – cone bearing plants
  • Angiosperms – flowering plants (monocot & dicot)
• Monocot


  • 1 cotyledon
  • isang sanga:mais
• Dicot


  • 2 cotyledons
  • sanga-sanga
• ALTERATION OF GENERATION


  1. Plant alternates between the diploid sporophyte and haploid gametophyte stages

  2. SPOROPHYTE is the diploid stage

  3. 1st sporophyte stage is in seeds

  4. GAMETOPHYTE is haploid stage

  5. MEIOSIS forms haploid spores

  6. MITOSIS forms haploid gametes

  7. FERTILIZATION – diploid chromosome number are restored (happens one the pollen penetrates the ovary of the flower.)

  8. POLLINATION – transfer of pollen grains from anther to stigma

  9. Embryogenesis and organogenesis are important processes that take place after the formation of seeds – lead to the formation of functional organs in a plant body
• FLORAL ANATOMY


  • PISTIL - consists of the female structures in flowers (i.e., stigma, style, ovary)
  • STIGMA - a structure where the pollen grains must land during pollination
  • STALK - Style is the stalk of the stigma that leads to the ovary. Within it is the pollen tube
  • OVARY - female structure in flowers that house the female gametes. (future seeds)
  • OVULES - small structures within the ovary. Each of them contains an egg nucleus. (future fruit)
  • STAMEN refers to the male portion of the flower. It consists of anthers and filaments
  • ANTHER - produces and stores the pollen grains
  • FILAMENTS - staminal structure that serves as the stalk of the anther
  • PETALS - primarily attract pollinators
  • SEPALS - green leaf-like structures that protect the structures in a flower bud
  • RECEPTACLE - thickened portion below the ovary where floral structures grow
  • PEDICEL - stalk of the flower which provides support to all floral parts
• ASEXUAL REPRODUCTION


  • Apomixis in some species of dandelions allows the production of embryos from unfertilized eggs in ovules
  • Vegetative propagation allows plant parts to produce buds that can develop into new individuals
• ASEXUAL REPRODUCTION – genetically identical to parents
• SEXUAL REPRODUCTION - Enhances genetic variation because the parents and offspring are not genetically identical
• SEXUAL REPRODUCTION


  • Pollen grains - The tube nucleus will transport the sperm during pollination
  • Each pollen grain consists of two sperm nuclei from the generative nucleus
  • Ovules - ovule or embryo sac in the ovary of the flower consist of eight nuclei
  • Only the polar nuclei and egg nucleus will have descendant in seeds
  • Double fertilization - produces a diploid embryo and a triploid endosperm
• Meristems


  • SHOOT APICAL MERISTEM - allows the continuous upward growth of the plant
  • CAMBIUM - allows further growth of stems and roots by increasing their thickness
  • ROOT APICAL MERISTEM - allows the continuous downward growth of roots