%0 Book %1 Tyree_Zimmermann_02 %A Tyree, M. T. %A Zimmermann, M. H. %C Heidelberg %D 2002 %I Springer %K bibtex-import citeulikeExport %T Xylem Structure and the Ascent of Sap %7 2

@book{Tyree_Zimmermann_02, added-at = {2019-03-31T01:14:40.000+0100}, address = {Heidelberg}, author = {Tyree, M. T. and Zimmermann, M. H.}, biburl = {https://www.bibsonomy.org/bibtex/20eaf6eb0a2b93a6e2e87ed18427a9eeb/dianella}, citeulike-article-id = {1524104}, comment = {(private-note)p7- how to measure vessel length distribution (the mathematics.) SEe pic, but. "the first difference in any row of column 3 is the difference between the count in column 2 of the same row minus the count in the row below. The second difference in any row of column 4 is the difference between the number in column 3 of the same row and the number in the row below. THe number of vessels in any row of column 6 is the product of the numbers in the same row of columns 4 and 5." where column 1=distance (cm); 2= count of paint filled; 3=first difference; 4= second difference; 5= steps to zero; 6= number of vessels; 7= vessels \% There are rules and algotithms to fix up negative values. p17- the HP eqn. Conductance vs conductivity. Conductivity= Kcapillary= flow rate (say in m3s-1) per unit pressure gradient (Pa/m). SInce pressure gradient is dP/dl, it incorporates length. (inverse is resistivity) COnductance= k = doesn't take into account the length. (inverse is resistance) Kcapillary= r4(pi)/8(n) Viscosity decreases by about 2.4\% per oC Turbulent flow is unlikely in capillaries the size of vessels. ? Oh well. In any case, Y = m-mo/Vw OH MY! The temperature of water also influences its water potential most dramatically. "Two drops of water that differ in temperature by 1k differ in water potential by about 7.7 MPa! " " Biologists generally ignore TS because it's hard to measure." Temperature gradients have little effect on water transport, apart from the effects of viscosity. "one occasionally encounters the myth that xulem water supercools substantially." The freezing point of xylem water is only a few hundredths of a degree below 0oC because the solute content is rather low. 'bound' water in wood (30-40\% of the dry weight) may remain unfrozen. early expts include: Lybeck (1959) who did the briggs expt with dry ice in the middle and got an embolism straight away Scholander et al (1961) who put the end of a rattan vine in a burette, then froze midway up and observed at different arrangements loss of water on thawing and then uptake again under positive pressures, and then resuming of normal water flow. Hammel (1967) saw no change in xylem pressure downstream of frozen twigs except while they were frozen a bit. Carte (1961) the bubble size and qty depend on freezing rate Sucoff(69) thought the water migrated irreversibly away from the frozen part of the plant. air is 1000 times less soluble in ice than in water. When water freezes, air comes out of solutionj.2.8 ml of air will come out of solution for every 100ml of air-saturated water frozen. When ice melts, if the tensions are above a critical threshold, the bubbles will expand. There is a diameter relationship.}, edition = 2, interhash = {e0b9b9190c07e425c5b551937c67c994}, intrahash = {0eaf6eb0a2b93a6e2e87ed18427a9eeb}, keywords = {bibtex-import citeulikeExport}, posted-at = {2007-07-31 07:39:10}, priority = {2}, publisher = {Springer}, timestamp = {2019-03-31T01:16:26.000+0100}, title = {{Xylem Structure and the Ascent of Sap}}, year = 2002 }