Ch. 4 Tissues Flashcards
Major organ groups of plants
o Roots
o Stems
o Leaves
o (flowers)
Tissue
composes organs
group of cells performing similar function
May be more than one tissue per organ
3 tissue patterns in roots and stems
woody dicots, herbaceous dicots, monocots
Meristems
permanent regions of growth and active cell division
Cells small, 6-sided, box-like; Large nuclei, small or absent vacuoles; Cells form different shapes in maturity
Vacuoles increase in size and may occupy more than 90% of cell volume
Apical meristems
tips of roots and shoots
develops leaves, buds, and 3 primary meristem types
Primary growth
apical meristems produce new cells, increase length of apical meristems
Name the 3 primary meristem types
protderm, ground meristem, and procambium
they all produce primary tissues
Lateral meristems
- contributes to secondary growth
- inclues vascular cambium and cork cambium
Secondary growth
lateral meristems produce secondary tissues that increase girth of roots and stems
Vascular cambium
- Thin cylinder of brick-shaped cells that extends the length of stems and roots
- Cambial cylinder often branches, except at the tips
- Individual remaining cells of the cambium are called initials, and their sister cells are called derivatives
Cork Cambium
- Lies outside vascular cambium just inside the outer bark; produces bark
- Periderm: outer bark of woody plant made with cork cells
Intercalary meristems
Grasses and related plants have apical meristems
Do not have vascular cambium nor cork cambium
Intercalary meristems present
Occur in vicinity of nodes (leaf attachment area) along stems, add to stem length
Simple tissues
composed of one cell type
o Parenchyma
o Collenchyma
o Sclerenchyma
Complex tissues
composed of 2+ cell types, some tissues produced by apical meristems
o Xylem
o Phloem
o Epidermis
o Periderm
Parenchyma
composed of parenchyma cells (various tissues and cell types)
o Important in tissue repair
o Thin, pliable walls
o 14-sides
o Living cytoplasm
o Often large vacuoles
o Various secretions
o Live for long time
o Have spaces between them
Name the type of Parenchyma cells and tissues
Aerenchyma, Chlorenchyma, Transfer Cells
Aerenchyma
parenchyma tissue with extensive connected air spaces, usually in aquatic plants
* Helps with buoyancy
Chlorenchyma
parenchyma containing chloroplasts that function in photosynthesis
Transfer Cells
develop irregular extensions of inner wall that increase rsurface area of plamsa membrane
* Nectaries of flowers
* Secreting fluids/oils for various purposes, significant
Collenchyma tissue
o Living cytoplasm
o May remain alive long time
o Thick cell walls
o Uneven thickeness
o Pliable, strong(Provide flexible support)
o Occurs just below epidermis
Sclerenchyma tissue
o Thick
o Tough
o Secondary walls, normally contain lignin
o Dead at maturity
o Function in support
Name the types of sclerhechyma tissues
Sclereids and fibers
Sclerids
Scatter in tissue
Cells as long as wide
Include stone cells
Fibers
Found in roots, stems, leaves, fruits
Much longer that wide and contain lumen (Lumen: tiny cavity)
Have been used by humans for thousands of years (Rope, string, canvas, textiles)
