Plant Anatomy and Tissue Structures

Size: px

Start display at page:

Download "Plant Anatomy and Tissue Structures"

Benedict Elwin Davidson
5 years ago
Views:

Plant Anatomy and Tissue Structures The Two Major Plant Systems Reproductive shoot (flower) Terminal bud Node Internode Angiosperm plants have threse

1 Plant Anatomy and Tissue Structures The Two Major Plant Systems Reproductive shoot (flower) Terminal bud Node Internode Angiosperm plants have threse major organs: Roots Stems Leaves & Flowers Terminal bud Vegetative shoot Leaf Blade Petiole Axillary bud Stem Taproot Lateral roots Shoot system Root system 1

2 The Three Tissue Systems Dermal tissue Ground tissue tissue Common Types of Plant Cells PARENCHYMA CELLS COLLENCHYMA CELLS 80 m Cortical parenchyma cells SCLERENCHYMA CELLS 5 m Sclereid cells in pear 25 m Cell wall Parenchyma cells 60 m Collenchyma cells Fiber cells 2

Common Types of Plant Cells WATER-CONDUCTING

Tracheids and vessels Vessel element Vessel

members: longitudinal view Companion cell

3 Common Types of Plant Cells WATER-CONDUCTING CELLS OF THE XYLEM Vessel Tracheids 100 m Pits Tracheids and vessels Vessel element Vessel elements with partially perforated end walls Tracheids Common Types of Plant Cells SUGAR-CONDUCTING CELLS OF THE PHLOEM Sieve-tube members: longitudinal view Companion cell Sievetube member Sieve plate Nucleus Cytoplasm Companion cell 30 m 15 m 3

structure- bundles are arranged in a ring example is a sunflower root fewer root hairs than monocots Some

4 Tissue Organization of Roots Key Dermal Ground Root hair cylinder Zone of maturation Zone of elongation Apical meristem Root cap Zone of cell division 100 m Tissue Organization of Roots DICOT root Organized structure- bundles are arranged in a ring example is a sunflower root fewer root hairs than monocots Some MONOCOT root Unorganized structure -scattered amongst cell in bundles example is a corn root many root hairs 4

Tissue Organization of Stems Sclerenchyma (fiber cells) Phloem Xylem Ground tissue connecting pith to cortex

(maize) Tissue Organization Of Leaves Cuticle Sclerenchyma fibers Key to labels Dermal Ground Stoma Guard cells

Bundlesheath cell Guard cells (a) Xylem Phloem Cutaway drawing of leaf tissues Guard cells Vein Cuticle Palisade

5 Tissue Organization of Stems Sclerenchyma (fiber cells) Phloem Xylem Ground tissue connecting pith to cortex Ground tissue bundle 1 mm Key Dermal Ground bundles 1 mm (a) An eudicot stem (sunflower) (b) A monocot stem (maize) Tissue Organization Of Leaves Cuticle Sclerenchyma fibers Key to labels Dermal Ground Stoma Guard cells Stomatal pore Epidermal cell 50 µm (b) Surface view of a spiderwort (Tradescantia) leaf (LM) Upper epidermis Bundlesheath cell Guard cells (a) Xylem Phloem Cutaway drawing of leaf tissues Guard cells Vein Cuticle Palisade mesophyll Spongy mesophyll Lower epidermis Vein Air spaces (c) Transverse section of a lilac (Syringa) leaf (LM) Guard cells 100 µm 5

6 Meristematic Tissue Within the meristems certain cells are able to divide repeatedly into two sister cells: 1. Initial - the self perpetuating sister cell that remains in the meristem 2. Derivative - the other sister cell which moves into the plant body. These may also continue to divide until they become differentiated into specific types of cells There are two types of meristems: Apical & Lateral (a) Apical Meristematic Tissue Apical Meristem occur at the tips of the roots and shoots and they are responsible for extension of the plant body. Apical meristems give rise to the primary tissues of the plant, forming the primary plant body. Since there are three tissue systems in plants, the apical meristem gives rise to three primary meristems: 1) Protoderm - gives rise to the outer, protective coating of the plant 2) Procambium - gives rise to the vascular tissue 3) Ground meristem - gives rise to ground tissue 6

(b) Lateral Meristematic Tissue Lateral Meristem responsible for lateral growth and they produce the secondary tissues which constitute the secondary plant body Lateral meristems are called cambia

7 (b) Lateral Meristematic Tissue Lateral Meristem responsible for lateral growth and they produce the secondary tissues which constitute the secondary plant body Lateral meristems are called cambia (cambium). There are two types: 1) cambium - gives rise to secondary vascular tissue, to the inside and phloem to the outside 2) Cork cambium - gives rise to mostly cork. It lies outside the vascular cambium. Intercalary meristems: Some grasses have neither a vascular cambium nor a cork cambium, but have this one. They develop at intervals along stems, and their tissues added to stem length 7

Primary and Growth Shoot apical meristems (in buds) Root apical meristems cambium Cork cambium Lateral meristems Primary Primary growth in stems

Primary phloem cambium Primary Periderm (mainly cork cambia and cork) Primary cambium Primary phloem Phloem ray 2 3 Xylem ray Primary cambium phloem

8 Primary and Growth Shoot apical meristems (in buds) Root apical meristems cambium Cork cambium Lateral meristems Primary Primary growth in stems growth in stems cambium Primary phloem Primary Periderm Cork cambium Primary phloem phloem Primary and secondary growth in a two-year-old stem Primary phloem cambium Primary Periderm (mainly cork cambia and cork) Primary cambium Primary phloem Phloem ray 2 3 Xylem ray Primary cambium phloem Primary phloem 4 First cork cambium 1 Cork 6 Primary phloem phloem cambium Primary cambium phloem 5 Most recent cork cambium 7 Cork 9 Bark Layers 8 of periderm 8

of a three-year-old stem (LM) Late wood Early wood phloem

9 Anatomy Of A Tree Trunk Growth ring ray Heartwood Sapwood cambium Bark phloem Layers of periderm Transverse section of a three-year-old stem (LM) Late wood Early wood phloem cambium Cork cambium Cork Periderm Xylem ray Bark 0.5 mm 0.5 mm 9

10 Tissue Organization Of Flower 10

11 Plumule - Embryo shoot 11

Plants. Tissues, Organs, and Systems

Plants. Tissues, Organs, and Systems Plants Tissues, Organs, and Systems Meristematic cells Specialized cells that are responsible for producing specialized cells, they produce three types of tissue in the body of a plant. Meristematic Cells