water relations

water relations

1. Water relations Presented by: Syeda Saba Kazmi Dated: 3/9/2015

2. OUTLINE

3. Earth: The Biosphere

4. %age of Water on Earth 3/4 th of earth surface is covered by Water

5. Phases of Water Gaseous phase: vapor and clouds in the sky Liquid Phase: seawater and rain etc. Solid Phase: icebergs in the polar oceans, glaciers

6. Water in Cell (Cytoplasm) fluid like material between the cell membrane and the nucleus (Cytoplasm) over 80 % water

7. Water in Plants Water constitutes 80-90% of the fresh weight of herbaceous plants, and more than 50% of woody species.

8. Structure of Water Chemical formula H2O: one molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom.

9. Physical & Chemical properties of water Taste, Odour & color Transmission of Light

10. Chemical and Physical properties of water Surface Tension: Boiling Point: 100 degrees Celsius Density of Water: Liquid Phase more dense

11. The Universal Solvent Polarity of Water:

12. Capillary action: The tendency of water to move up a narrow tube against the force of gravity. E.g. vascular plants, such as trees.

13. hydrogen bonding Each water molecule is connected to another water molecule through weak bonding known as hydrogen bonding

14. The Soil Plant Atmosphere Continuum(SPAC) The Soil-Plant-Atmosphere Continuum (SPAC) is the pathway for water moving from soil through plants to the atmosphere.

15. Cell Water related terminologies Cohesion: water molecules stick together, a process known as cohesion. Adhesion: When water molecules form hydrogen bonds with other molecules.

16. Cell Water related terminologies ( cont …) Cohesion The attraction water to itself – H bonds

17. Cell Water related terminologies ( cont …) Adhesion The attraction of water to other surfaces/substances

18. Cell Water related terminologies ( cont …) Osmosis: Movement of water from higher concentration to lower concentration through membrane. Active transport: Reverse of osmosis, energy is utilized

19. Hydrophilic- attracts water & Hydrophobic- repels water

20. Cell Water related terminologies ( cont …) Evapotranspiration Transpiration is the water vapor given off plants Evaporation is the water vapor lost from the soil Evapotranspiration is the sum of both (Et)

21. Water pathway through the leaf

22. water potential . Water potential is the property of water that determines which way it will flow, which depends on the concentration of solutes in the water. Greek letter psi, which looks like this: Ψ.

23. Components of Water Potential Pressure potential ( ψp ). -Difference between pressure of the water in cell and that of the atmosphere= turgor pressure Osmotic pressure (solute potential) ( ψs ). -Affect of concentrations of solutes inside vs outside the cell that influence osmosis Vapor potential Gravitational potential

24. Pressure Potential Turgid cell (left) have a high positive pressure potential. Cells that are flaccid or plasmolysed (right) have a pressure potential of zero .

25. Tonicity

26. Water Movement Between Plant Cells The path through the plasmodesmata is called the symplast Apoplast is a path through cell walls and intracellular spaces.

27. Absorption of water Active absorption It is the absorption of water by roots with the help of metabolic energy generated by the root respiration .(types) Active osmotic water absorption Active non osmotic water absorption Passive absorption This mechanism is carried out without utilization of metabolic energy

28. Aquaporin Aquaporins are integral membrane proteins from a larger family of major intrinsic proteins (MIP) that form pores in the membrane of biological cells .

29. Discovery 2003 Nobel Prize in Chemistry was awarded jointly to Peter Agre for the discovery of aquaporin Roderick MacKinnon for his work on the structure and mechanism of potassium channels

30. Function Aquaporins are "the plumbing system for cells," said Agre . Also known as water channels Aquaporins selectively conduct water molecules in and out of the cell

31. Beta-Barrel Alpha Helix Amphipathic Helix Fatty acid Chain GPI-Anchored Peripheral Types of Membrane Proteins

32. Structure Aquaporin proteins are made up of six transmembrane α-helices arranged in a right-handed bundle, with the amino and the carboxyl terminals.

33. Aquaporins In plants The presence of aquaporins in the cell membranes seems to serve to facilitate the transcellular symplastic pathway for water transport

34. Types(in plants) Aquaporins in plants are separated into five main homologous subfamilies, or groups: 1: Plasma membrane Intrinsic Protein (PIP) 2: Tonoplast Intrinsic Protein (TIP) 3: Nodulin-26 like Intrinsic Protein (NIP) 4: Small basic Intrinsic Protein (SIP) 5: X Intrinsic Protein (XIP)

35. Hofler Diagram: Analysis of change in torgor and osmotic potential Small changes in cell volume give large changes in ψp Hofler slop is actually the study of elastic modulus(rigidity) of cell wall

36. Pressure volume curve

37. Osmoregulation Osmoregulation is the active regulation of the osmotic pressure of an organism fluids Regulators and conformers

38. Osmoregulation in plants While there are no specific osmoregulatory organs in higher plants, the stomata are important in regulating water loss through evapotranspiration. Xerophytes Hydrophytes Mesophytes

39. Hydraulic conductivity Hydraulic conductivity is a property of vascular plants, soils and rocks, that describes the ease with which a fluid (usually water) can move through pore spaces or fractures.

40. Methods of determination There are two broad categories of determining hydraulic conductivity: Empirical approach by which the hydraulic conductivity is correlated to soil properties like pore size and particle size (grain size) distributions and soil texture. Experimental approach by which the hydraulic conductivity is determined from hydraulic experiments.

41. Psychrometry Psychrometry is the science of study of various properties of air, method of controlling its temperature and moisture content or humidity and its effect on various materials and human beings.

42. Composition of Air

43. Psychrometric Properties of Air Psychrometry is the science of air . S tudy of psychrometric properties of air like : T emperature , R elative humidity dew point temperature Composition of air

44. References http ://www.tutorvista.com/content/biology/biology-iv/plant-water-relations/absorption-water-by-plants.php http://www.springerlink.com/content/qw62632354v4nm77/ http://www.ictinternational.com.au/appnotes/ICT101.htm http://www.jstor.org/stable/4353618 http://www.wiziq.com/tutorial/70692-Biology-XI-11-Transport-in-plants-4-Mechanism-of-Water-Absorption http://www.uoguelph.ca/~mgoss/four/410_N05.html www.slideworld.com/.../Water-relation-Soil-Plant-Atmosphere- continu https ://frank.itlab.us/learning/xylem.ppt www.prairiesoilsandcrops.ca/articles/volume-6-11-screen.pdf https ://pilgrimapbio.files.wordpress.com/2011/11/water-potential.ppt