Tissues
PLANT TISSUES
(pp 261-268)
HOW ARE CELLS ORGANIZED IN PLANTS?
I. MERISTEMATIC TISSUES
A. APICAL MERISTEMS Primary Growth
1. Initials
a. Occur near tips of roots and shoots
b. Cells have thin walls, prominent nuclei, and small vacuoles
c. Functions
1) Establish patterns of growth.
• Leaf pattern.
2) Produce new, genetically healthy cells
3) Produce derivatives which in turn account for primary growth i.e. elongation.
2. Derivatives
a. Protoderm - becomes the epidermis
b. Procambium - becomes the vascular tissue (xylem and phloem)
c. Ground Meristem - becomes the cortex and pith
B. LATERAL MERISTEMS - Secondary Growth
1. Vascular Cambium
a. Secondary Xylem
b. Secondary Phloem
2. Cork Cambium
a. Periderm (bark)
C. INTERCALARY MERISTEMS
1. Most common in grasses
2. Occur at base of nodes
II. NON-MERISTEMATIC TISSUES A. PRIMARY TISSUES 1. GROUND TISSUES
a. General
1) Differentiates from ground meristem
2) Constitutes most of primary plant body
3) Found as part of other tissues (e.g. vascular)
4) Functions
• Storage
• Basic metabolism
• Support
b. Parenchyma
1) Cortex of stems & leaves, pith of stems, leaf mesophyll, flesh of fruits.
2) Capable of cell division
3) Role in regeneration and wound response.
4) Adventitious roots on stem cuttings
5) Secretion
6) Storage
7) Photosynthesis c. Collenchyma
1) Living at maturity
2) Associated with epidermis of stems and petioles and bordering veins in dicot leaves (strings on celery)
3) Typically elongated cells with unevenly thickened cell walls.
4) Function in support.
d. Sclerenchyma
1) Fibers are long slender non living support cells occurring in strands or bundles. Hemp, jute and flax.
2) Sclereids are short non living cells at maturity; dispersed throughout ground tissues.
• They are the seed coats, shells of nuts, the stone of stone fruits and the
(pp 261-268)
HOW ARE CELLS ORGANIZED IN PLANTS?
I. MERISTEMATIC TISSUES
A. APICAL MERISTEMS Primary Growth
1. Initials
a. Occur near tips of roots and shoots
b. Cells have thin walls, prominent nuclei, and small vacuoles
c. Functions
1) Establish patterns of growth.
• Leaf pattern.
2) Produce new, genetically healthy cells
3) Produce derivatives which in turn account for primary growth i.e. elongation.
2. Derivatives
a. Protoderm - becomes the epidermis
b. Procambium - becomes the vascular tissue (xylem and phloem)
c. Ground Meristem - becomes the cortex and pith
B. LATERAL MERISTEMS - Secondary Growth
1. Vascular Cambium
a. Secondary Xylem
b. Secondary Phloem
2. Cork Cambium
a. Periderm (bark)
C. INTERCALARY MERISTEMS
1. Most common in grasses
2. Occur at base of nodes
II. NON-MERISTEMATIC TISSUES A. PRIMARY TISSUES 1. GROUND TISSUES
a. General
1) Differentiates from ground meristem
2) Constitutes most of primary plant body
3) Found as part of other tissues (e.g. vascular)
4) Functions
• Storage
• Basic metabolism
• Support
b. Parenchyma
1) Cortex of stems & leaves, pith of stems, leaf mesophyll, flesh of fruits.
2) Capable of cell division
3) Role in regeneration and wound response.
4) Adventitious roots on stem cuttings
5) Secretion
6) Storage
7) Photosynthesis c. Collenchyma
1) Living at maturity
2) Associated with epidermis of stems and petioles and bordering veins in dicot leaves (strings on celery)
3) Typically elongated cells with unevenly thickened cell walls.
4) Function in support.
d. Sclerenchyma
1) Fibers are long slender non living support cells occurring in strands or bundles. Hemp, jute and flax.
2) Sclereids are short non living cells at maturity; dispersed throughout ground tissues.
• They are the seed coats, shells of nuts, the stone of stone fruits and the