Plant Tissue Systems Plant Structure and Growth Vascular Plant Body Shoot System – Root System – Growth Determinate and Indeterminate Growth – Primary and Secondary Growth – Classes of Flowering Plants Monocots and Eudicots Compared – Lifespans – Plant Tissue Ground Tissue - Vascular Tissue - Dermal Tissue - Primary Shoot Systems Features – Functions – Stems – Leaves – Secondary Shoot Systems Growth – Woody Stem Structure – Root Systems Types of Roots – Zones of Primary Root Growth – Root Tissues –

Describe the three main tissue systems in the plant body. Unit II Plants Learning Goal 2 Describe the three main tissue systems in the plant body.

Plant Structure and Growth The Vascular Plant Body Shoot system Stems Leaves Flowers/Fruits Root system Roots Root Hairs Root Cap

Growth Determinate growth common in animals growth stops at a certain age Indeterminate growth Plant grows throughout life Meristems give rise to plant body Increase in number of cells Increase in size of cells

Primary Growth Apical meristems at root and shoot tips Increases height of shoot, length of roots

Secondary Growth Lateral meristems at root and shoot tips Self-perpetuating cylinder of tissue Increases diameter of stems and roots

Classes of Flowering Plants Eudicots and Monocots Compared

Lifespans Annual (one growing season) Biennial (two growing seasons) Herbaceous Biennial (two growing seasons) Roots, stems, and leaves first season Flowers, fruits, and seeds second season Perennial (growth continues year after year)

Plant Tissues Ground Tissue Parenchyma Soft primary tissues Thin primary cell walls, pliable and permeable Specialized for storage, secretion, photosynthesis

Collenchyma Flexible support Thicker primary cell walls Elongated cells in strands or sheathlike cylinder

Rigid support and protection Sclerenchyma Rigid support and protection Thick secondary cell walls Sclerids (protective casings) and fibers (support)

Vascular Tissues Xylem Tracheids Vessel members Conducts water and dissolved minerals Thick, lignified secondary walls Dead when functional Tracheids Elongated, tapered, overlapping ends Lateral connections through pits Vessel members Shorter, tubelike columns Lateral connections through pits and perforations

Tracheids and Vessel Members

Phloem Sieve tube members Conduct sugars and other solutes Living when functional Sieve tube members Joined end to end in sieve tubes Sieve tube cells assisted by companion cells End walls (sieve plates) studded with pores

Sieve Tube Members

Dermal Tissue Epidermis covers primary plant body Waxy cuticle layer restricts water loss Pairs of guard cells in leaf epidermis create stomata (openings) for gas exchange Epidermal specializations Trichomes (hairs) Absorbent root hairs

Epidermal Tissue

Primary Shoot Systems Features Stems are adapted to provide support, routes for vascular tissues, storage, and new growth Leaves carry out photosynthesis and gas exchange Plant shoots may have juvenile and adult forms

Consists of main stem, leaves, and buds Plus any attached flowers and fruits Functions: Mechanical support House vascular tissues May store food and water Buds and meristems for growth

Stems Organized into modular segments Nodes: Where leaves and buds are attached Internodes: Between nodes Terminal bud: At apex of main shoot Lateral buds: In leaf axils, produce branches

Stem Structure

Eudicot Vascular Bundles Form a stele (cylinder) Outer cortex, inner pith

Monocot Vascular Bundles Scattered throughout ground tissue of stem

Modified Stems

Leaves Blade Petiole (in eudicots) Large surface area for photosynthesis and gas exchange Petiole (in eudicots) Attaches leaf to stem

Leaf Forms b. Simple leaves (eudicot) A new plant species from Idaho. Sacajawea’s bitterroot (Lewisia sacajaweana) was formally described in 2006. It is named in honor of Sacajawea, the Native American woman who guided Lewis and Clark in their exploration of the Pacifi c Northwest in the early 1800s. Poplar (Populus) Oak (Quercus) Maple (Acer) Fig. 31.15, p. 725

A new plant species from Idaho. Sacajawea’s bitterroot (Lewisia c. Compound leaves (eudicot) Leaflets A new plant species from Idaho. Sacajawea’s bitterroot (Lewisia sacajaweana) was formally described in 2006. It is named in honor of Sacajawea, the Native American woman who guided Lewis and Clark in their exploration of the Pacifi c Northwest in the early 1800s. Red Buckeye (Aesculus) Black Locust (Robinia) Honey Locust (Gleditsia) Petiolule Fig. 31.15, p. 725

Leaf Adaptations Responses to environmental and herbivore pressures

Leaf Internal Structure

Secondary Shoot Systems Growth Vascular cambium gives rise to secondary growth in stems Secondary growth can also occur in roots Secondary growth is an adaptive response

Increases girth of roots and stems Vascular cambium Produces secondary xylem and phloem Cork cambium Produces cork, part of protective bark

Woody Stem Structure Vascular cambium produces wood Cork cambium produces cork Bark Living and nonliving tissue outside vascular cambium (secondary phloem and periderm) Periderm Cork, cork cambium, and secondary cortex

Heartwood, sapwood

Root Systems Features Taproot and fibrous root systems are specialized for particular functions Root structure is specialized for underground growth

Absorb water and dissolved minerals Conduct water and minerals to aerial plant parts Anchor and support aboveground parts Often store food

Types of Roots

Zones of Primary Root Growth Zone of cell division Root cap Quiescent center Zone of elongation Zone of maturation

A new plant species from Idaho. Sacajawea’s bitterroot (Lewisia a. Eudicot root Stele (vascular cylinder) Primary phloem Primary xylem A new plant species from Idaho. Sacajawea’s bitterroot (Lewisia sacajaweana) was formally described in 2006. It is named in honor of Sacajawea, the Native American woman who guided Lewis and Clark in their exploration of the Pacifi c Northwest in the early 1800s. Pericycle Endodermis Root cortex Epidermis Fig. 31.21, p. 730

A new plant species from Idaho. Sacajawea’s bitterroot (Lewisia b. Monocot root Pith Root cortex Epidermis Stele A new plant species from Idaho. Sacajawea’s bitterroot (Lewisia sacajaweana) was formally described in 2006. It is named in honor of Sacajawea, the Native American woman who guided Lewis and Clark in their exploration of the Pacifi c Northwest in the early 1800s. Primary xylem Primary phloem Fig. 31.21, p. 730

Root Tissues Exodermis Endodermis Pericycle Outer layer of root cortex Inner layer of root cortex Pericycle Between stele and endodermis Can function as meristem

LG 2 Vocabulary Terms Apical/Lateral Meristems - Parenchyma - Collenchyma - 4. Sclerenchyma - Cambium - Trachied - Nodes - Pith - Sieve Tube - Root Cortex -