Plant Anatomy

Title :

Plant Anatomy

Author :

Kim Foglia & Kelly Reidell

Number of slides:

31

Slideshow :

Content transcript :

Basic plant anatomy 1

* root

* root tip

* root hairs

Plant Body Hierarchy

* Tissue

* Cells with a common function

* Organ

* 3 basic organs

* Roots

* Stems

* Leaves

Roots 

* Roots anchor plant in soil, absorb 

minerals & water, & store food

* fibrous roots (1)

* mat of thin roots that spread out

* monocots

* tap roots (2)

* 1 large vertical root 

* also produces many small lateral, 

or branch roots 

* dicots

* root hairs (3)

* increase absorptive 

surface area

Basic plant anatomy 2

* root

* root tip

* root hairs

* shoot (stem)

* nodes

* internodes

* buds

* terminal or apical buds

* axillary buds

* flower buds & flowers

Modified shoots

Basic plant anatomy 3

* root

* root tip

* root hairs

* shoot (stem)

* nodes

* internodes

* buds

* terminal or apical buds

* axillary buds

* flower buds & flowers 

* leaves

* mesophyll tissue

* veins (vascular bundles)

Leaves

* Function of leaves

* photosynthesis

* energy production

* CHO production

* gas exchange

* transpiration

Modified leaves

Interdependent systems

* Both systems depend on the other

* roots depend on  sugars produced by photosynthetic leaves

* shoots depend on water & minerals absorbed from the soil by roots

Plant TISSUES

* Dermal

* epidermis (“skin” of plant)

* single layer of tightly packed cells that covers 

& protects plant

* Ground

* bulk of plant tissue 

* photosynthetic mesophyll, storage 

* Vascular

* transport system in 

shoots & roots 

* xylem & phloem

Plant CELL types in plant tissues

* Parenchyma

* “typical” plant cells = least specialized

* photosynthetic cells, storage cells

* tissue of leaves, stem, fruit, storage roots

* Collenchyma

* unevenly thickened primary walls

* support

* Sclerenchyma 

* very thick, “woody” secondary walls

* support

* rigid cells that can’t elongate

* dead at functional maturity

Parenchyma

Collenchyma 

Sclerenchyma

* Thick, rigid cell wall

* lignin (wood)

* cannot elongate

* mostly dead at maturity

* Cells for support

* xylem vessels

* xylem tracheids

* fibers

* rope fibers

* sclereids

* nutshells

* seed coats 

* grittiness in pears

Phloem: food-conducting cells

Phloem: food-conducting cells

Phloem

* Living cells at functional maturity

* cell membrane, cytoplasm

* control of diffusion

* lose their nucleus, ribosomes & vacuole

* more room for specialized transport of 

liquid food (sucrose)

* Cells 

* sieve tubes

* sieve plates — end walls — have pores to facilitate flow of fluid between cells

* companion cells

* nucleated cells connected to the sieve-tube 

* help sieve tubes

Vascular tissue in stems

Vascular tissue in roots: dicot

Vascular tissue in roots: monocot

Putting it all together 

* Obtaining raw materials

* sunlight

* leaves = solar collectors

* CO2

* stomates = gas exchange

* H2O

* uptake from roots

* nutrients

* uptake from roots

Plant Growth

* Apical meristem

* Growth in length

* Primary

* Lateral meristem

* Growth in diameter

* Secondary

Growth in woody plants

* Woody plants grow in height from tip

* primary growth

* apical meristem

* Woody plants grow in diameter from sides

* secondary growth

* lateral meristems

* vascular cambium

* makes 2° phloem & 2° xylem

* cork cambium

* makes bark

Primary growth of roots

* Root cap

* Protects root as it grows

* Cell division (mitosis)

* Cells small

* Cell elongation

* Cell differentiation

* Cells mature into 

final cell types

Primary growth of stems

* Shoot apical meristem

* Dividing cells at shoot tip

* Develop from axillary bud on stem’s surface

Secondary plant growth: vascular cambium

* Adds secondary xylem & phloem

* Thickens roots & stems

* Heartwood

* Close to center

* Does not transport water 

* Sapwood

* Transport xylem sap

* Outer layers

Secondary plant growth:  cork cambium

* Periderm

* Cork cambium & tissues

* Produces thick covering

* Protects from water loss

* Phelloderm

* Thin layer of parenchyma

* Secondary tissue

* Exterior of cork cambium

* Suberin - waxy