Tissues and the Primary Growth of Stems
Types of Tissues and Cells
Collenchyma cells
Parenchyma Cells
mass forms parenchyma tissues
Chlorenchyma Cells
Glandular Cells and secretion includes
Large extensive plasma membrane
Some Dies of maturity to function
May Create openings to release pollen and seeds
Form spaces to allow diffusion of gases within leaves
Contain large amount of dictysomes and ER
Secretions Includes
Metabolize Sugar and minerals
Nectar
Fragnance
Oil
resins
Mucilage
numerous amount of chloroplast
Thin cell walls
Involve in photosynthesis
allows light and CO2 to pass through readily
Transfer Cells
Used for short distance transport
contains numerous molecular pumps
increases surface Area
Thin primary cell wall
inexpensive metabolically
mechanical Sclerenchyma
Image
prevalent in shoot tips and petioles
Primary cell wall
Thick in other, especially in corner
exhibits plasticity
present in shoots tips of vining plants
layer under epidermis or band next to vascular bundles
Parenchyma cells in inner tissue provide support
Long Fibers
Short sclereids
found in areas where strength and flexibility is required
prevalent in wood of the most flowering plants
more flexible
isodiometric
brtittle and inflexible
mass forms
shells walnuts and coconuts
"pits" or "stone" of cherries and peaches
Arrangements of primary tissues
Epidermis
Phloem
Vascular Tissue
Cortex
Xylem
Vascular Bundles
Has two types of cell tracheid and vessel elements
It is initially a small parenchyma cell
Has only a thin primary wall
Has xylem and Phloem
It is not a circulatory system
Thin sheet of cell
Diffusion is adequate of the distribution of sugar
outermost surface of an herbaceous stem
single layer of parenchyma cells
It work as a barrier against invasion by bacteria
it is also water proofing
sieve cells and sieve tube members
have only primary walls
Has two conducting cells
their plasmodesmata enlarge to a diameter
it is quit simple and homogeous
interior to the epidermis is cortex
most of the plants fit together compact
xylem and phloem occurs together
arranged in one ring surrounding the pith
all are collateral
Fibers
Steam growth and differentiation
Vessel elements
Sclereids
more or less isodiametric
often dead at maturity
long many types are dead
others type remain alive and are involved in storage
found almost exclusively in flowering plant
short and wide with rather perpendicular end wall
dead at maturity
produce progenitor cells for the rest time
stems grow longer by creating new cells at their tips
cells divide by mitosis and cytokinesis
External organization of Stems 
In this stem is an axis
shoot is the stem plus any leaves, flowers or buds that may be present
Internal Organization of stem 
It is an arrangement of primary tissue
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