1 / 34

Plant Structures Roots, Stems, and Leaves

Plant Structures Roots, Stems, and Leaves. Chapter 23. 23-1 Specialized Tissues in Plants. Plants are as successful if not more successful than animals Seed plants have three main structures: Roots Stems Leaves Linked together by various means. 23-1 Specialized Tissues in Plants. Roots

rocco
Download Presentation

Plant Structures Roots, Stems, and Leaves

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Plant StructuresRoots, Stems, and Leaves Chapter 23

  2. 23-1 Specialized Tissues in Plants • Plants are as successful if not more successful than animals • Seed plants have three main structures: • Roots • Stems • Leaves • Linked together by various means

  3. 23-1 Specialized Tissues in Plants • Roots • Absorbs water and nutrients • Anchor plant to the ground • Hold soil in place and prevent erosion • Protect from soil bacteria • Transport water and nutrients • Provide upright support

  4. 23-1 Specialized Tissues in Plants • Stems • Support for the plant body • Carries nutrients throughout plant • Defense system to protect against predators and infection • Few millimeters to 100 meters

  5. 23-1 Specialized Tissues in Plants • Leaves • Main photosynthetic systems • Suseptable to extreme drying • Sight of oxygen/carbon dioxide intake and release

  6. 23-1 Specialized Tissues in Plants • Plant tissue systems • Exist within the root, stems, and leaves • Dermal tissue • Vascular tissue • Ground tissue

  7. 23-1 Specialized Tissues in Plants • Dermal Tissue • Outer covering • Single layer of cells • Cuticle – waxy coating • Trichomes – Spiny projections on the leaf • Roots have dermal tissue • Root hairs • Guard Cells

  8. 23-1 Specialized Tissues in Plants • Vascular Tissue • Transport System • Subsystems • Xylem • Phloem • Subsystems are used to carry fluids throughout plant

  9. 23-1 Specialized Tissues in Plants • Xylem • Two types • Seed plants • Angiosperms • Tracheid – long narrow cells • Walls are connected to neighboring cells • Will eventually die • Vessel Element – wider that trachieds

  10. 23-1 Specialized Tissues in Plants • Phloem • Sieve Tube Elements • Cells arranged end to end • Pump sugars and other foods • Companion Cells • Surround sieve tube elements • Support phloem cells

  11. 23-1 Specialized Tissues in Plants • Ground Tissue • Cells between dermal and vascular tissue • Parenchyma • Thin cell walls, large vacuoules • Collenchyma • Strong, flexible cell walls • Sclerenchyma • Extremely thick, rigid cell walls

  12. 23-1 Specialized Tissues in Plants • Plant Growth • Meristems – tissues responsible for growth • Undifferentiated cells • Apical Meristem • Produce growth increased length • Differentiation • Cells will assume roles in the plant • Flower Development • Starts in the meristem

  13. 23-2 Roots • Types of Roots • Taproots • Found in dicots • Long, thick root • Hickory and oak trees • Fibrous roots • Found in monocots • No single root larger than any other • Many thin roots

  14. 23-2 Roots • Root Structure • Outside layer • Epidermis • Root hairs • Cortex • Central cylinder – vascular system • Root Cap – cellular production • Key role in water/mineral transport

  15. 23-2 Roots • Root Functions • Anchor plant • Absorb water • Absorb nutrients

  16. 23-2 Roots • Plant Nutrient Uptake • Soil type determines plant type • Plant requirements • Oxygen, CO2 • Nitrogen • Phosphorus • Postassium • Magnesium • Calcium • Trace elements

  17. 23-2 Roots • Active Transport in Plants • Root hairs use ATP • Pump minerals from soil • Causes water molecules to follow by osmosis • Vascular Cylinder • Casparian Strip – water retention • Root Pressure • Forces water up into the plant

  18. 23-3 Stems • Stem Structure • Produce leaves, branches, and flowers • Hold leaves up • Transport substance between roots and leaves • Essential part of transport system • Function in storage and photosynthesis

  19. 23-3 Stems • Xylem and phloem – major tubule systems • Transport water and nutrients • Composed of three tissue layers • Contain nodes – attachment for leaves • Internodes – regions between the nodes • Buds – undeveloped tissue

  20. 23-3 Stems • Stem Types • Monocot – vascular bundles are scattered throughout • Distinct epidermis • Dicot – vascular tissue arranged in a cylinder • Pith – parenchyma cells inside the ring

  21. 23-3 Stems • Stem Growth • Primary growth – new cells produced at the root tips and shoots • Increases the length • Secondary growth – increase in stem width • Vascular cambium – produces tissue and increases thickness • Cork cambium – produces outer covering of stems

  22. 23-3 Stems • Formation of Vascular Cambium • Xylem and phloem bundles present intially • Secondary growth initiates production of a thin layer • The vascular cambium divides • Produces new xylem and phloem

  23. 23-3 Stems • Formation of wood • Wood – layers of exlem • Produced year after year • Results from the older xylem not conducting water – heartwood • Becomes darker with age • Sapwood – surrounds heartwood

  24. 23-3 Roots • Formation of Bark • All the tissues outside the vascular cambium • Consists of outermost layers of dead cork • Water proof

  25. 23-4 Leaves • Main sight of photosynthesis • Consist of: • Blade – thin flattened section • Petiole – stalk that attaches stem to blade • Covered by epidermis and cuticle • Create water proof barrier

  26. 23-4 Leaves • Leaf Functions • Photosynthesis – occurs in the mesophyll • Palisade mesophyll – absorb light • Spongy mesophyll – beneath palisede level • Stomata – pores in the underside of the leaf • Guard Cells – Surround the stomata

  27. 23-4 Leaves • Transpiration • Loss of water through its leaves • Replaced by water drawn into the leaf

  28. 23-4 Leaves • Gas Exchange • Take in CO2 and release O2 • Can also do the opposite – How? • Gas exchange takes place at the stomata • Not open all the time • Stomata is controlled by water pressure in guard cells

  29. 23-5 Transport in Plants • Water Transport • Active transport and root pressure • Cause water to move from soil to roots • Capillary action • Combined with active transport and root pressure, moves materials throughout the plant

  30. 23-5 Transport in Plants • Capillary Transport • Capillary transport results from both cohesive and adhesive forces • Water molecules attracted to one another • Water is also attracted to the xylem tubes in the plant • Causes water to move from roots to the stem and upward

  31. 23-5 Transport in Plants • Transpiration • Evaporation is the major moving force • As water is lost, osmotic pressure moves water out of vascular tissue • This pulls water up from the stem to the leaves • Affected by heat, humidity, and wind

  32. 23-5 Transport in Plants • Controlling Transpiration • Open the stomata – increase water loss • Close the stomata – decrease water loss

  33. 23-5 Transport in Plants • Transpiration and Wilting • Osmotic pressure – keeps plants semi-rigid • Wilting is a result of high transpiration rates • Loss of water causes a drop in osmotic pressure • Loss of rigidity • Conserves water

  34. 23-5 Transport in Plants • Nutrient Transport • Most nutrients are pushed through plant • Nutrient movement takes place in phloem • Source to Sink • Source – any cell that produces sugars • Sink – any cell where sugars are used • Pressure-flow Hypothesis

More Related