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Plant Tissues and Organs. Fig. 38.6. Fig. 38.4. Figure 35.21 Modular construction of a shoot. Basic Plant Morphology. TISSUES - a group of cells functioning together in some specialized activity
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Basic Plant Morphology • TISSUES- a group of cells functioning together in some specialized activity • MERISTEMS- a mass of self-perpetuating cells, which are not yet committed to developing into a specialized cell type • Terminal meristems- ends of stems, branches and roots • Axillary meristems- base of leaves, branches • Lateral meristems are parallel to sides of plant parts and increase girth.
Meristem types • Primary • Apical Meristems • Secondary • Vascular cambium • Cork Cambium
Flowering plants have 3 basic tissue types • Dermal • Cover surface of plant • Protection • Ground • Vascular • Conducting tissue
Dermal • Epidermis • epidermal cells • Periderm • cork cells
Vascular Tissue • Xylem • Mostly to conduct water and nutrients • E.g., roots to shoots • Phloem • Mostly to conduct sugars, amino acids, etc. • E.g., leaves to roots or flowers
Vegetative Organs • Roots • Stems • Leaves
Function of roots • Anchor the plant • Absorb water and minerals from soil • Storage
Longitudinal section of roots • Root cap • Zone of cell division • Zone of cell elongation • Zone of maturation
Cross section of root • Vascular bundle (Stele) = contains xylem and phloem • Cortex • Epidermis • Root hairs • Absorb water and minerals
Function of Stems • support leaves to maximize light absorption • part of conduit for transport of water, minerals, and organic solutes • storage
Woody dicots • Discrete vascular bundles replaced by continuous rings of xylem • Each ring is xylem produced during one growing season • Vascular cambium
Stems: Secondary growth • Vascular tissue, (xylem) makes up the bulk of the stem • Form tree rings
Function of leaves • Main photosynthetic structure
Leaf parts • Blade • Petiole • Pair of stipules
Figure 35.8c Modified leaves: Succulent leaves for storing water
Figure 35.8d Modified leaves: Brightly-colored leaves to attract pollinators
Comparison of monocots & dicots • Monocotyledon • grasses • lilies, tulips • trees: palm • dicotyledon • roses, asters • grapes, beans • trees: oak, maple,