Chemical tolerant: Venus flytrap http://www.bbc.co.uk/nature/life/Venus_Flytrap#p004p9np

Cold tolerant: Arctic poppy

Dry and heat tolerant: sanguaro cactus

Fire tolerant: giant sequoia

Altitude tolerant :White Bark Pine

PLANTS Masters of adaptation

PLANTSCan we live without them? What do we use them for?

EDIBLE

MEDICINAL

BUILDING

CLOTHING

DYES, PAINTS, INKS AND PAPER

FERTILIZERS

FIRE AND LIGHTING

…

Redwood Sequoia sempervivens

How do they manage? Mix stiffness + flexibility

• Cellulose• Tubes from specialized cells• Stiffness lignin

Cellulose fibrils

Plant cell wall

Cellulose versus Starch

Glycosidic bond 1,4 Glycosidic bond 1,4

CelluloseStarch

Cellulose versus Starch

CHARACTERISTIC STARCH CELLULOSE

Glucose ALPHA BETA

Orientation Same Opposite

Number of glucose 200-5000 Up to 10000

TYPE OF BOND Glycosidic 1,4Glycosidic 1,6 (branch)

Glycosidic 1,4

Branching Yes No

Property Energy storage Strength

Can we digest? Yes No

http://www.uwfox.uwc.edu/users/joyperry/bot130/Chapter04/Animations_videos/4_4_2_struct_funct.swf

Cellulose versus Starch

Animation quiz

Cellulose microfibrils/macrofibrils

Microfibrils

Hydrogen bonds

A hydrogen bond is the attractive force between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule.

THE GLUE: Hemicelluloses and pectins (polyssacharides)

Uses of pectin

• Gelling sugar• Medicinal: increases viscosity (against diarrhea)• Cosmetic: stabilizer

What happens if plants does not form cellulose then?

Examples of plasmodesmata

Synthesis Activity

Kahoot!

How do they manage? Mix stiffness + flexibility

• Cellulose• Tubes from specialized cells• Stiffness lignin

Can you name the three main plant tissues?

• Dermal tissues• Ground tissue• Vascular tissue

Dermal Tissue• Generally a single layer of cells• The "skin" of the plant• Primarily parenchyma cells• Main role is protection of the plant

Ground Tissue• Makes up the bulk of the plant• Predominately parenchyma• Diverse functions including photosynthesis,

storage, and support

Vascular Tissue• Involved in the transport of water, ions,

minerals, and food• Also has a secondary role in support• Composed of xylem, phloem, parenchyma,

schlerenchyma

1 vascular bundle: Xylem vessels

Phloem sieve tubes

Sclerenchyma tissue

Xylem vessels

Characteristics

• Large cells/thick cell walls• Waterproofed (lignin)• Tonoplast breaks: autolysis (dead)

Xylem vessels (lignification)

Lignin is a complex organic polymer

Phloem sieve tubes

Characteristics

• Sieve tubes have no nucleus, ribosomes or vacuoles • Depend on companion cells• Connected by sieve plates

Xylem Phloem

Cells DeadXylem vessels

LivingPhloem sieve tubes

Cell wall Thick Thin

Cell wall composition Lignin Cellulose

Permeability Impermeable Permeable

Cytoplasm None Cyt lining

Transports Water/Mineral Nutrient

Carried to Leaves Growing parts and storage organs

Direction of flow Upwards Up and down

Activity

Identification of vascular bundles and their components in Arabidopsis samples

Environmental conditions influences development

Long day

Short day

Water transport in plants

https://www.youtube.com/watch?v=60SgZgK3Gss

Introduction video

Water transport in plants: important concepts Transpiration: water evaporation from the plant (at the leaves and trough stomata)

Water potential: tendency of water to move from one area to another (Ψ). Caused by osmosis, gravity and surface tension of water. https://www.khanacademy.org/science/physics/fluids/fluid-dynamics/v/surface-tension-and-adhesionTranspiration: water vapor goes out of the leaves trough stomata

Xylem: transports water from the root (high water potential) to the leaves (low water potential)

Adhesion: Attraction of water molecules to a surface

Cohesion: Hydrogen bonding between water molecules

Phloem: transports carbohydrates and aminoacids produced in the leaves to other organs

Translocation: transport of sucrose or other solutes from leaves to other parts of the plant

COHESION-TENSION THEORY

Important Water properties

• Cohesion and surface tension

• Solvent properties

• Thermal properties

• Density and freezing properties

What else does xylem transports?

• Inorganic ions: nitrate ions (important for aminoacids synthesis, chlorophyll, nucleic acids, ATP…)

• Insufficient amounts of inorganic ions cause symptoms in plants Magnesium: yellow leaves Calcium: stunted growth

Brassica oleracea wildBrassica oleracea

mutant cauliflower

Brassica oleracea mutant cauliflowermicroscopic detail

Arabidopsis thaliana Arabidopsis thaliana mutant “cauliflower”

Arabidopsis thaliana mutant cauliflowermicroscopic detail

Model species/cultivated species