plant structure (leaves, stems, roots)

18
Plant Structure (Leaves, Stems, Roots) Honors Biology

Upload: oliana

Post on 23-Feb-2016

65 views

Category:

Documents


0 download

DESCRIPTION

Plant Structure (Leaves, Stems, Roots) . Honors Biology. Plant Body. Shoot system = leaves + stem Root system Meristem = cells that divide for life of plant, can give rise to all plant structures 3 BASIC Organs Roots Stems Leaves. 2 BASIC Systems BOTH SYSTEMS DEPEND ON THE OTHER - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: Plant Structure (Leaves, Stems, Roots)

Plant Structure (Leaves, Stems, Roots)

Honors Biology

Page 2: Plant Structure (Leaves, Stems, Roots)

Plant Body• Shoot system = leaves

+ stem• Root system• Meristem = cells that

divide for life of plant, can give rise to all plant structures

3 BASIC Organs– Roots– Stems– Leaves

Page 3: Plant Structure (Leaves, Stems, Roots)

2 BASIC Systems• BOTH SYSTEMS DEPEND ON THE

OTHER–Root System (roots)

receive sugars and other nutrients from photosynthetic parts– Shoot System (leaves and

stems) depends on water & minerals absorbed from the soil by roots.

Page 4: Plant Structure (Leaves, Stems, Roots)

Tissue Types in Vascular Plants• Dermal Tissue

– Covers/ protects plant– Makes cuticle on stems/ leaves– Allows for better H2O absorption

(root hairs)– Make guard cells

• Vascular Tissue (xylem & phloem)– Transport and support– Throughout the plant– Called “veins” in leaves– Called the “stele” in stem or root

• Ground Tissue– Between dermal and vascular tissues– Storage– Photosynthesis (makes sugars)– Support

Dermaltissue

Vasculartissue

Groundtissue

Page 5: Plant Structure (Leaves, Stems, Roots)

Plant Body-LEAF

Functions– Exposes surface to sunlight– Major site of photosynthesis– Conserves water– Provides for gas exchange– Transpiration-water movement throughout the

plant; evaporation of water from plant leaves

Blade

Petiole

Leaf = blade + petiole

Stoma = opening in the leaf for

gas exchange, water evaporation

Page 6: Plant Structure (Leaves, Stems, Roots)

Leaf Structure-Dermal layers• Cuticle-The thin waxy

covering on the outer surface of the leaf has a thin waxy covering This layer's primary function is to prevent water loss within the leaf. (Plants that live entirely within water do not have a cuticle).

• Directly underneath the cuticle is a layer of cells called the epidermis (upper and lower)

Page 7: Plant Structure (Leaves, Stems, Roots)

Leaf Tissues• Mesophyll

– Ground tissue between upper and lower epidermis

– Two types:• Palisade parenchyma (mesophyll) cells

– Lots of chloroplasts in these cells– Most photosynthesis occurs here

• Spongy parenchyma (mesophyll) cells– Lots of air spaces where O2 and CO2

circulate– Near stomata (Think: sponges have lots

of air spaces)

• Veins– Xylem and phloem are continuous from

roots through stem to leaves

Page 8: Plant Structure (Leaves, Stems, Roots)

Vascular Tissue (Veins)• Transports materials in roots, stems,

& leaves.• Xylem (dead cells-water conducting)– Carry water & minerals up from roots– Tube-shaped dead cells

• Their walls are used as water pipes

• Phloem (living cells-food conducting)– Carry nutrients (food) throughout

plant• SUGARS (sucrose), amino acids….

– Tube-shaped living cells

Page 9: Plant Structure (Leaves, Stems, Roots)

Stomata and Guard Cells• The underside portion of a leaf has stomata and is the site of

transpiration (water loss) and gas exchange.

Page 10: Plant Structure (Leaves, Stems, Roots)

Stomata help regulate the rate of transpiration

• Guard cells –2 cells on either side of stomata

(surrounds stomata)–regulate water loss

• What conditions will promote closing of guard cells?–Hot, dry, windy conditions

Page 11: Plant Structure (Leaves, Stems, Roots)

Stoma Opening/Closing

• http://academic.kellogg.edu/herbrandsonc/bio111/animations/0021.swf

Page 12: Plant Structure (Leaves, Stems, Roots)

Plant Body- ROOTSRoot Functions• Anchors plant in

soil • Takes up water and

minerals from soil

Page 13: Plant Structure (Leaves, Stems, Roots)

& gymnosperms

Page 14: Plant Structure (Leaves, Stems, Roots)

Modified Roots• Some plants have modified

roots • Adventitious roots arise

aboveground spread over large areas

• Storage roots hold “food” called root tubers

Page 15: Plant Structure (Leaves, Stems, Roots)

Plant Body-STEMStem: series of nodes and internodesFunctions• Support for the plant body • Holds leaves up to light• Transports nutrients throughout plant

Xylem conducts waterand minerals

Phloem transports sugar

Page 16: Plant Structure (Leaves, Stems, Roots)

Division of Meristem Cells Causes Plant Growth

• Apical Meristem– tips of root and

shoot– increase in height

• Lateral Meristem– cylinders within

plant body– increase in width

Page 17: Plant Structure (Leaves, Stems, Roots)

• Apical meristems are located at the tips of roots and in the buds of shoots– elongate shoots and roots, a process called primary

growth• Lateral meristems

– add thickness ONLY to woody plants, a process called secondary growth

Types of Meristems (like embryonic stem cells)

Page 18: Plant Structure (Leaves, Stems, Roots)

MONOCOT PLANTS vs. DICOT PLANTS– Monocots: grasses, lilies, orchids, corn, palms, onions– Dicots (aka-Eudicots): broadleaf trees, shrubs, most flowers,

and vegetables.