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Structure of Woody Plants secstem07 (Vascular Cambium (Growth Rings (These…

- - - - Helps the plant move water and minerals upward and carbohydrates downward due to possession of conducting tissue
- - - - Cells located between the metaxylem and metaphloem that never stop dividing
      - This term is only used for developing cambia
        
        Begins to become indistinguishable from interfascicular cambium after a few years
    - - Mature parenchyma cells between vascular bundles that come out of cell cycle arrest and resume mitosis
      - Surrounded by fascicular cambia on each side
      - This term is only used for developing cambia
        
        Begins to become indistinguishable from fascicular cambium after a few years
  - - - Long, Tapered Cells
      - Can be anywhere from 140 micrometers (smaller individuals in dicots) to nearly a centimeter (larger individuals in conifers)
      - Produces two elongate cells after performing longitudinal cell division with a wall parallel to the cambium's circumference
        
        This wall is called the periclinal wall
        
        One remains the fusiform initial
        
        One differentiates into a secondary xylem or secondary phloem
        
        When the innermost cell remains part of the cambium, the outermost cell differentiates into a secondary phloem
        
        When the outermost cell remains part of the cambium, the innermost cell differentiates into a secondary xylem
        
        This process seems random as to which cell differentiates
        
        There are almost always more xylem than phloem, however
      - Has thin primary walls
    - - Similar to fusiform initials save for the following characteristics
        
        Short and cuboidal
        
        When differentiating, will form cells that are specialized for storage or support instead of xylem or phloem
      - Goes into greater detail here
  - - - Division is a necessity for the Vasular Cambium because it must not be too wide or it cannot function properly
  - - - The name for these arrangements as uniseriate, biseriate, and multiseriate, respectively
      - These formations are collectively called 'rays'
        
        The purpose of ray cells is to store nutrients during dormancy and to aid in conduction across short distances in the wood
        
        This is achieved by feeding nutrients into the axial system
        
        Basic types of ray parenchyma cells
        
        Upright Cells
        
        Comes into contact with axial cells in all trees in which it is present
        
        Upright cells that are in contact with axial cells form plasmodesmata
        
        Plasmodesmata are basically channels from one cell to another
        
        The starch from upright cells are the first to be transported to the axial system and converted to sugar during spring
        
        Procumbent Cells
        
        Will have no direct contact with axial cells in some trees
        
        In those in which they do, they will have thinner cell walls on the side facing the axial cell
    - - The names for these arrangements are storied cambium and nonstoried cambium, respectively
  - - - Components
        
        Early Wood
        
        Also known as spring wood
        
        Contains many large vessels or tracheids for transporting enough water and nutrients
        
        Forms during times when the plant needs very high conduction capacity
        
        Late Wood
        
        Also known as summer wood
        
        Late wood contains smaller vascular tissue but usually boasts more fibers to hold up an ever-growing tree
        
        Growth Ring
        
        The growth ring is the early and late wood put together
        
        Clear marker between growth rings by the dark lines formed during cambium's dormancy
- - - - Arrangement reflects fusiform and ray initials
        
        Radial system derived from ray initials
        
        Axial system derived from fusiform initials
        
        In woody angiosperms, this system will also often contain fibers that give added strength and flexibility to the wood
        
        These fibers are very common in commercially important trees, since they are some of the most useful for construction purposes
        
        These woody angiosperms are called hardwoods
        
        This term is applied to all wood of basal angiosperms and eudicots, regardless of the presence of the fibers that result in their strength
        
        Trees with few or no fibers, such as the conifers, are called softwoods
        
        Despite the name, there are instances of softwoods being much harder than softwoods
        
        Always contains tracheary elements
        
        These carry out longitudinal conduction of water through wood
        
        These tracheary elements are naturally elongate, as vascular tissue
        
        However, they may differentiate instead into xylem parenchyma when they are immature
        
        These are used to store water until the plant needs it
        
        2 more items...
        
        This is called axial xylem parenchyma
        
        Complexity of axial system varies from tree to tree
        
        Some angiosperms will only have tracheids, but most will have all types of cells
  - - - Growth rings of these branches are much wider towards the top
    - - Growth rings of these branches are much wider towards the bottom
- - - - Angiosperms will have sieve tube members and companion cells
      - Conifers will have sieve cells
      - Regardless of plant type, fibers and nonconducting parenchyma are typically present
- - - - Serves as a barrier against outside threats
      - Maintains the integrity of the tree against the pressure during growth
        
        Similar Purpose
    - - Inner cells remain cork cambium; outer cells turns into cork cells
        
        Cork cells are also called phellem cells
        
        Collectively called the phellem
        
        The phellem, phellogen, and phelloderm are components of the periderm
        
        Cork cells die soon after maturation
        
        The cells lose nutritional value after death, so animals won't try to eat it
        
        Due to this, new cork cells must be made occassionally
    - - This layer is called the phelloderm
    - - Can be anywhere from within the first year to fourty years
  - - - Cork will develop these areas as they mature as a result of becoming rounder