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Erstellt von J yadonknow
vor mehr als 6 Jahre
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Frage | Antworten |
Ψ = | Ψ s+ Ψ p+ Ψ g |
Ψ g | Gravitational potential Gravy causes water to move downward Difference btw. neighbouring cells is negligible Generally omitted when considering water transport at the cellular level |
Solute motential | always negative |
Ψ p | Effect of pressure on water potential positive = turgid cell negative = xylem Ψ p=Ompa (atmospheric pressure) |
Ψ s= | iCRT i= ionisation constant so NaCl =2, glucose = 1 C=conc. R=0.0831 T=temperature in K |
Bar to mPa | 2.4 bar= 0.24 mPa |
Dissolved sugar into water | Ψ p=0mPa [0.1] solute Ψ s=-0.244mPa Ψ = Ψ s+ Ψ p Ψ = -0.244+0 Ψcell=-0.244 mPa |
Plasmolysed Turgid Flaccid | Ψcell>Ψs Ψcell<Ψs Ψcell=Ψs |
Soil-plant-air continuum | H2O absorbed through roots H2O travels through plant H2O evaporates through leaves |
Boundary layer in transpiration | Layer of unstirred air next to leaf surface H2O(g) must diffuse through this Thickness of layer determined by wind speed and leaf size |
What air conditions makes the leaf thicker? | In still air layer is thicker |
Cavitation | When an embolism appears in H2O column negative pressure gets too great water column snaps air cavity formed Water flow stops |
Overcoming this | Vessels and tracheids are connected by pits so can bypass embolisms |
Which system of vessels are more vulnerable to cavitation? | Vessels Tradeoff btw. flow rate and risk of cavitations |
Tracheary elements in gymnosperms | Most only tracheids, not vessels |
Cavitation repair | Positive root pressure from guttation |
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