Download - Making use of biodiversity
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