Plant Growth and Development Part IPlant Growth and Development Part I 

Levels of Organization

Whole PlantWhole Plant

OrgansOrgans

TissuesTissues

CellsCells

OrganellesOrganelles

MacromoleculesMacromolecules

Levels of Organization

Whole PlantWhole Plant

OrgansOrgans

TissuesTissues

CellsCells

OrganellesOrganelles

MacromoleculesMacromolecules

Plant Cells

Differentiation in CellsDifferentiation in Cells Refers to the process by which distinct 

plant cells arise from precursor cells and become different than each otherbecome different than each other

Unique adaptation of plants

Levels of Organization

Whole PlantWhole Plant

OrgansOrgans

TissuesTissues

CellsCells

OrganellesOrganelles

MacromoleculesMacromolecules

Plant Tissues – Xylem and PhloemPlant Tissues  Xylem and Phloem

= xylem•Transports water and minerals from the roots to the plant parts•Moves only in one direction

= phloemM h h ( )•Moves photosynthates (sugars)

throughout the plant•Moves both directions

These internal tissues are also important for supporting the plant….

Movement of water through the plant: Transpiration Stomata – microscopic openings, usually

on the bottom of a leaf, important for gas exchange and transpiration

http://www.fairchildgarden.org/EduProfDev/Leaf_anatomy.htmlHeat

Vascular cambiumVascular cambium

•Located between the xylem and phloemp•Produces new xylem and phloem tissue•Responsible for increasing stem diameter

Vascular cambium

stem diameter.

Phloem, Xylem and the  Cambium Layery y

Knowing the cambium layer is important when looking at wood boring insectsKnowing the cambium layer is important when looking at wood boring insects and disease – such as mountain pine beetle

Knowing the Cambium Layer is Important for Plant Grafting

Or, why leaving trees tied for too long or 

Why letting the 13‐year‐old weed whipWhy letting the 13 year old weed whip around trees

Is a bad thing…

VASCULAR BUNDLE

PHLOEM

V SCU UN

XYLEM

CAMBIUM

PITH

EPIDERMIS

http://www.fairchildgarden.org/EduProfDev/Leaf_anatomy.htmlhttp://www.fairchildgarden.org/EduProfDev/Leaf_anatomy.html

Vascular Bundle ArrangementVascular Bundle Arrangement

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Monocot (grass) Dicot (broadleaf)

Levels of organization

Whole PlantWhole Plant

OrgansOrgans

TissuesTissues

CellsCells

OrganellesOrganelles

MacromoleculesMacromolecules

Vegetative Organs (plant parts)Vegetative Organs (plant parts)

StemStemLeafRootRootShootB dBud

Asexual (vegetative) Reproduction

Asexual ReproductionAsexual Reproduction

Offspring arise from a single parent

The Function of StemsThe Function of Stems

Mechanical support and ec a ca suppo t a ddisplay

Movement of water and minerals up to the leaves

Movement of photosynthates (sugars) to other parts of the plants

A l tiAsexual propagationStorage

http://www.gimcracker.com/blab/archives/2002 12.html

Modified Stems

Can grow above and below ground

Crown

and below ground

Stolon

Rhizome

Corm

Bulb

Tuber

Spur

Woody StemsWoody Stems

ShootShootSoft young stem with leaves

TwigTwigDormant stem one year old 

BranchStem over one year old

TrunkMain stem of a woody planty p

The Parts of a Woody StemThe Parts of a Woody Stem

22

Parts of a Plant ShootParts of a Plant Shoot

Leaf primordiaLeaf primordia

Shoot apexTh ti f th h tThe tip of the shoot

Axillary bud

Parts of a Plant ShootParts of a Plant Shoot

NodeNodeArea on the stem where a leaf anotherwhere a leaf, another stem, or flower bud is located 

InternodeSpace between theSpace between the nodes on a stem

Vegetative BudsVegetative BudsA bud is an undeveloped shoot that producesshoot that produces leaves and/or flower parts

Determining One Year’s GrowthDetermining One Year s Growth

A Plant’s Life Cycle – AnnualsA Plant s Life Cycle  Annuals

AnnualsAnnualsCompletes life cycle in 1 year

Grow, mature, bloom, produce seed and die

l l h i Summer annuals complete their life cycle in spring and summer

Winter annuals complete theirWinter annuals complete their life cycle during the fall and winter.

Usually easy to pull out of the ground

Summer Annual WeedsSummer Annual Weeds

Black medicBlack medic

Pigweed

i l dPineapple weed

Purslane

Winter Annual WeedsWinter Annual Weeds

ChickweedChickweed

Henbit

Penny cress

A Plant’s Life Cycle – BiennialsA Plant s Life Cycle  Biennials BiennialsRequires all or part of 2 years to complete its life cycley

Vegetative 1st yearOverwinters Fl d f i 2nd Flowers and fruits 2nd year

Bolting (flowering in oneBolting (flowering in one year) may occur in extreme environmental conditions

A Plant’s Life Cycle – PerennialsA Plant s Life Cycle  Perennials

PerennialsPerennialsLive for many years

WoodyTrees and shrubs

HerbaceousWhat are the issues with reading about herbaceous perennialsDie back to the ground 

in Montana

herbaceous perennials on the Internet or in popular publications?

How about leaves?How about leaves?

Dartmouth.edu

The inside story

http://www.fairchildgarden.org/EduProfDev/Leaf_anatomy.htmlhttp://www.fairchildgarden.org/EduProfDev/Leaf_anatomy.html

Functions of LeavesFunctions of Leaves

Food manufacture – photosynthesisFood manufacture  photosynthesis

Functions of LeavesFunctions of Leaves

Protection of delicate tissues like budsProtection of delicate tissues like budsBud scales

Floral bractsFloral bracts

Sepals

St C t l d b lbStorage – Cotyledons, bulbs

Plant Identification KeyPlant Identification Key

Blade (lamina)Leaf StructureStructure

Apex BaseApex

Vein

Margin Petiole

Types of Leaves – VenationTypes of Leaves  Venation

Monocot (grass) Dicot (broadleaf)

Types of Leaves – Simple LeavesTypes of Leaves  Simple Leaves

Types of Leaves – Compound LeavesTypes of Leaves  Compound Leaves

Leaf ArrangementLeaf Arrangement

Opposite Whorled Alternate

Leaf Shapes and MarginsLeaf Shapes and Margins

Plant Identification KeyPlant Identification Key

RootsRoots

AnchoragegNutrient and water absorptionStorageStorageAerial supportP i ( i )Propagation (sometimes)

Roots that are not growing cannot absorb nutrients

Cross Section of a RootCross Section of a Root Root cap Protection Protection

Apical meristem region Cell division

Elongation Pushes root through soil

Differentiation Differentiation Root hairs and secondary 

roots Root hairs Root hairs Absorb water and 

nutrients

RootsRoots

Modified RootsSwollen root

P tProp roots

Radicle

Reproductive OrgansReproductive Organs

FlowersFlowers

Fruits

Flower buds

SeedsSeeds

Sexual ReproductionSexual Reproduction

Parts of a FlowerSepal

Usually green; protect the flower when it is in bud

PetalAttract pollinators

Pistil ♀♀StigmaStigma

Pollen falls and developsStyle

Stalklike part between the stigma and ovary

OvaryEnlarged part of the Pistil that containing ovules

Stamen ♂♂Anther

The part of the stamen that contains the pollen

FilamentStalk of the stamen

Parts of a Flower

♀♀ -- PistilPistil

StiStiStigmaStigma

StyleStyleStyleStyle

♂♂ -- StamenStamen

AntherAnther

Fil tFil tFilamentFilament

How about flowers . . .How about flowers . . . 

♂ ♀♀

“My squash is putting out a lot of flowers, but I am not getting any fruit…”

How about flowers . . . 

♂ ♀♂ ♀

How about flowers . . .How about flowers . . . 

Not all flowers have both ot a o e s a e botmale and female parts

Some plants may containSome plants may contain only male or female flowers♂

We will discuss this more in following classes

♂g

♀♀

Composite FlowersComposite Flowers

Inflorescence (Flower) TypesInflorescence (Flower) Types

Plant Identification KeyPlant Identification Key 

Questions?Questions?