How do we classify and group plants? What are the major divisions? How are they grouped and...

How do we classify and group plants?

• What are the major divisions?

• How are they grouped and classified?

• How do you use a plant identification key?

Plant Taxonomy

• Nonvascular Plants- have small reduced leaves, no vascular tissue( veins) no true roots, and reproduce by spores or flagellated cells that travel through water.

Vascular Plants- have true roots, stems, and leaves with vascular tissue. Xylem- water and minerals. Phloem- transports carbohydrates

Plant Divisions• nonvascular Bryophyta- mosses

• vascular seedless Lycophyta-club moss Pterophyta-Ferns seed plants Gymnosperms-naked seeds Angiosperms-flowering plants

Gymnosperm Coniferophyta- needle or scale leaf, cones ( conifer)Anthophyta or Angiosperm Monocots- parallel veins, petals in 3’s Dicots- net veins, petals in 4’s or 5’s

BryotphytesMosses

Moses

• Non-vascular Plants- No tissues to carry water

• Spores used for reproduction

• No true roots, stem

• Reduced leaves

Liverworts

sporophyte

gametophyte

Mosses

sporophyte

gametophyte

In mosses the dominant stage of their life cycle they only have half of their total chromosme

number.

Spore Producing

• Spores are reproductive stages that have only half the chromosomes or genetic material.

VASCULAR PLANTS

Lycopodium,Lycophyta

Pterophyta

Ferns- reproduce with spores but have veins to carry water

Gymnosperms

Naked seeds or seeds produced in cones.

Angiosperms or Anthophyta

• Flowering plants

• Seeds produced within a fleshy fruit with gametes borne within a flower.

Antheridium Archegonium

Liliacea

Taxonomy key\identification key

• You always have two choices in a description of the organisms characteristic

• Choose the correct choice and it takes you to a name or a number.

dicot

monocot

Opposite Leaf arrangement

Alternate leaf arrangement

Botany

•Tissues, Organs, and Systems

Vascular Tissue

Xylem (wood)

trachieds and vessel elements make up xylem. They are nonliving tubes with openings at the ends to carry water .

Transport in Vascular Plants

• Water and minerals begin movement by osmosis.

through root and root hair

Transport in Plants cont.

capillary action in xylem vessel element

Adhesion-water vessel wall

Cohesion- water to water

Transpiration- water moves out through stoma in the leaf.

closed

H2O

Loss of TurgorTurgor

• Phloem carries carbohydrates

sieve tube elements-- connected by sieve plates

Heart wood

Springwood

Summer WoodVascularcambium

phloemCork cambium

CORK

Phloem rays

Vascular Tissue

• Xylem- wood, carries water

Spring wood- larger openings smaller ring

Summer wood – more compact rigs are wider

Phloem- carries sugar

phloem rays carry back and forth

Growth Tissue

• Vascular Cambium- grows new xylem to the inside and phloem to the outside

• Cork cambium- grows new cork to the outside

BARK- is vascular cambium, phloem, cork cambium , and cork

xylem

phloemCortex ( storage, support)(7,8)

11

4 & 5

Merristematic Regions

• Apical Bud

• Root Tips

Leaf PrimordiaApical Meristem

Axillary Bud

Roots

primary

secondary

TAP

DIFFUSE

Germination

• Seeds begin to grow as a result of cell division using much oxygen

seeds need warm temperatures, water, and oxygen to germinate but the seed supplies the food.

hypocotyl

Embryonic Tissue

Seed leaves of an embryo

Below the cotyledon

Above the cotyledon

Embryonic root

cap

merristematicElongation

maturation

Leaves- the main photosynthetic parts of a plant

• Types of

Simple

Compound

Pinnate

Palmate

Leaf Cross Section• Epidermis- prevents water loss

protects from UV light

• Palisades- photosynthesis zone ( contains much chlorophyll)

• Mesophyll ( spongy layer)- storage of gases, water and sugar

• Veins – contain xylem and phloem

• Abscision layer- cuts base of leaf off during defoliation

Stomate

• Stomate- leaf opening for gas exchange and water loss

• Guard Cells- control opening of stomate

• Stoma - opening

Photosynthesis

CO2+H2O light CnH2n0n+O2

Light- measured as an absorption spectrum, the wavelengths that are most important are different for different types of autotrophs

Photosyntheis

• Plant takes in carbon dioxide\

• Plant takes up water

• Plant produces sugars

• Plant gives off oxygen

petiole

Margin (serrate)

Pinnate veins

Simple Leaf with Entire Margin and Pinnate Veins

Angiosperms or Anthophyta

• Flowering plants

• Seeds produced within a fleshy fruit with gametes borne within a flower.

Perfect Flower

STAMEN- male part of flower

Filament

Anther

stigma

style

ovary3n2n

Zygote is 2n

Endosperm -food for development 3n

Pollen tube

Ovules within the ovary contain an embryo

PISTIL or CARPEL

Composite Family

Flower Structures

• Stamen- male floral part

• Anther- produces pollen ( n) haploid

• Filament- stalk that supports stamen

Floral Parts

• Pistil- female floral part

• Style- stalk that supports stigma

• Stigma- sticky part attracts pollen

• Ovary- eggs develop and are fertilized to become seeds

Plant Response to Light –Photoperiodism

LONG DAY_ require 12 hr. daylight or more to flower

SHORT DAY-require less than 12 hr daylight

DAY NEUTRAL – flower according to maturity not light

Plant Hormones

• Alter cell division

• Increase elongation

• Regulate gene activity

Auxins

Plant Auxin on Agar Block

Auxin Mutants