Specializations of Cells, Tissues, and Systems in Plants

• Dermal Tissue: also known as the epidermis is the outer layer of cells typically one or two cell layers thick

  • shoot system
  • dermal tissue of the root system organs is responsible for the uptake of water and minerals from the soil
  • in the leaves and stems, involved in gas exchange of carbon dioxide and oxygen
• Root hairs increase the surface area for absorption of water.
• Ground Tissue: makes up the majority of the plant and is found as a layer beneath the epidermis

  • provides strength and support for the stem
  • involved in food and water storage in the roots
  • In the leaves, it is the location where photosynthesis occurs

  
• Vascular Tissue: responsible for the transportation of materials throughout the plant

  • Xylem tissue
  • Phloem Tissue

  
• Xylem Tissue: moves water and dissolved minerals from the roots up the stem to the leaves where it's used in photosynthesis

  • Xylem vessels are thick-walled tubes
  • as it mature, they fuse together and the walls become perforated
  • leaves the non-living cell walls attached together like a long straw

  
• Phloem Tissue: transports sucrose and other dissolved sugars from the leaves to other parts of the plant

  • formed from individual long sieve tube cells that have perforated end walls
  • remains alive, but lose their nuclei
  • connected to small, companion cells that direct their activities

  
• Cuticle: a waxy substance that covers the epidermal cells, that prevents water from uncontrollably evaporating from the leaf

  
• Specialized cells in the epidermis are called guard cells. It forms tiny openings called stomata that allow gas exchange to happen.
• Stomata: tiny openings in the epidermis

  • Close at night to prevent water loss
  • most of the stomata is found on the underside of the leaf to prevent water loss
  • where exchange of carbon dioxide and oxygen occurs
  • guard cells that surround the stomata control
• Palisade Mesophyll: found just below the upper epidermis

  • cells are tightly packed together to maximize exposure to the sun
  • responsible for photosynthesis --> contains many chloroplasts

  
• Spongy Mesophyll: between the palisade mesophyll and the lower epidermis

  • increased spaces between the cells for gases to diffuse throughout the leaf
  • also contain some chloroplasts for photosynthesis

  
• The xylem and phloem tissues are bundled in a vascular bundle.