Plants and Animals: Development Process

• Plant organs


  Roots, Stems, and Leaves

  
• Roots


  • Anchor a vascular plant in the soil
  • Absorb minerals and water
  • Often store carbohydrates

  
• Taproot system


  • Most eudicots and gymnosperms have
• Fibrous root system


  • Most monocots have (a mat of generally thin roots spreading out below the soil surface)

  
• Root hair


  • A thin, tubular extension of a root epidermal cell
  • Main function is absorption

  
• Evolutionary adaptations of roots

  • Prop roots
  • Storage roots
  • "Strangling" aerial roots
  • Buttress roots
  • Pneumatophores or Air roots
• Prop roots


  Provide support to tall and top-heavy trees

  
• Storage roots


  Store food and water in their roots
• "Strangling" aerial roots


  Snakelike roots that wrap around the host tree
• Buttress roots


  Shallow root system
• Pneumatophores or Air roots


  Roots that grow above the soil surface

  
• Root functions


  • Anchor a plant in the ground
  • Absorb water and dissolve nutrients from soil
  • Uptake of plant nutrients (Nitrogen, Phosphorus, Potassium, Magnesium, Calcium)

  
• Nitrogen


  • Proper leaf growth and color; synthesis of amino acids, proteins, nucleic acids, and chlorophyll
  • Deficiency results in stunted plant growth and pale yellow leaves
• Phosphorus


  • Synthesis of DNA; Development of roots, stems, flowers, and seeds
  • Deficiency results in poor flowering and stunted growth
• Potassium


  • Synthesis of Proteins and carbohydrates; development of roots, stems, and flowers; resistance to cold and disease
  • Deficiency results in weak stems, stunted roots, and edges of leaves turning brown
• Magnesium

  • Synthesis of chlorophyll
  • Deficiency results in thin stems and mottled, pale leaves
• Calcium


  • Cell growth and division; cell wall structure; cellular transport; enzyme action
  • Deficiency results in stunted growth and curled leaves
• Stems


  • Raise or separate leaves, exposing them to sunlight
  • Raise reproductive structures, facilitating dispersal of pollen and fruit
  • Have nodes, internodes, axillary buds, and apical buds

  
• Apical dominance


  The inhibition of axillary buds by an apical bud
• Modified stems


  • Rhizomes
  • Bulbs
  • Stolons
  • Tubers
• Rhizomes


  Horizontal shoots that grow just below the surface

  
• Bulbs


  Vertical underground shoots consisting mostly of the enlarged bases of leaves that store food

  
• Stolons


  Horizontal shoots that grow along the surface
• Tubers


  Enlarged ends of rhizomes or stolons specialized for storing food
• Leaves


  • The main photosynthetic organ
  • Have a blade and stalk (petiole)

  
• Evolutionary adaptations of leaves

  • Tendrils
  • Spines
  • Storage leaves
  • Reproductive leaves
  • Bracts
• Tendrils


  Modified leaves used for support
• Spines


  Leaves adapted for protection
• Storage leaves


  Leaves adapted for storing water
• Reproductive leaves


  Leaves that produce adventitious plantlets, which fall off the leaf and take root in the soil
• Bracts


  Brightly colored leaves
• Plant tissue systems


  • Dermal
  • Vascular
  • Ground
• Plant cell types


  • Parenchyma
  • Collenchyma
  • Sclerenchyma
  • Water-conducting
  • Sugar-conducting
• Indeterminate growth


  Growth throughout the plant's life
• Determinate growth


  Growth that stops after reaching a certain size
• Meristems


  Undifferentiated tissue that divides when conditions permit
• Types of meristems


  • Apical Meristems
  • Lateral Meristems
• Apical Meristems


  • Located at the tips of roots and shoots and in axillary buds of shoots
  • Responsible for primary growth (length)

  
• Lateral Meristems


  • Called the vascular cambium and cork cambium
  • Responsible for secondary growth (thickness)
• Initials/stem cells


  Undifferentiated cells that divide to produce derivatives