Chapter 31 - Plant, structure, growth, and differentiation
 

Herbaceous vs.  Woody  plants
 
 

• Annuals - flower and die in one year

• Biennials - flower during their second year and die

• Perennials - flower yearly

Cells   -   Tissues    -   Organs
 
 

There are 4 kinds of plant tissues:
 

1.   Ground tissue
 

  - Parenchyma cells are living working cells with thin primary walls that have a number of functions:  photosynthesis, storage, and secretion
 
 

  - Collenchyma cells provide support for a plant and have unevenly thickened cell walls.
 
 

  - Sclerenchyma cells provide structural support - cells have primary and secondary cell walls
 

•    Sclereids (are short Sclerenchyma cells)

•     Fibers (are long Sclerenchyma cells)

2.     Vascular tissue
 
 

  - Xylem  (Tracheids, Vessel elements) Conduct water and dissolved nutrient minerals.
 
 
 
 
 
 

  - Phloem (Sieve tube members,  companion cells) Conducts carbohydrates formed during photosynthesis.
 
 
 
 

3.  Dermal tissue (epidermis)
 
 

  - cuticle
 
 

  - parenchyma cells
 
 

  - guard cells: specialized dermal cells that surround openings (stomata)  in the epidermis.
 
 

  - trichomes (root hairs)
 
 
 

4.   Meristematic tissue
 

•  Where Mitosis occurs - This results in  plant growth

Plant growth:  Plants have 2 types of growth.
 
 

Primary growth  - increase in length of the plant.

•    Apical meristems at the tips of the stem and roots result in primary growth

Secondary growth  -  Cell division at the Lateral Meristems increases the width of the plant.  This is referred to as Secondary growth and it only occurs in woody plants.  There are 2 types of Lateral Meristems.
 

             -             1. Vascular cambium ( produces secondary xylem and secondary phloem)
 
 
 

             -             2. Cork cambium (periderm)