ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Sap flow measurements in grapevines (Vitis vinifera L.) 1. Stem morphology and use of the heat balance method (1999)
    Springer
    Plant and soil 215 (1999), S. 39-45 
    Details
    ISSN: 1573-5036
    Keywords: Huber value ; modelling ; Vitis ; water use ; xylem flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The heat balance method was evaluated in detail for its use in older, mature grapevines with stems of 35 – 45 mm in diameter. Dye colouring of the xylem vessels revealed that even 21 year old grapevines did not show any development of heartwood and that xylem vessels of that age still have the capacity to transport water. A comparison of weight loss of potted vines on a balance and sap flow measurements demonstrated that the heat balance system reflected rapid changes in flow rate without any time delay. However, since even 20 year old xylem vessels of grapevines have the capacity to conduct water, the heater band was not able to heat the sap in all year rings evenly. Apparently, at low flow rates this effect was small and sap flow was calculated correctly. With increasing flow rates large thermal heterogeneities developed upsetting the calculation of the heat balance and mass flow. Consequently, actual sap flow was overestimated by 50 to 100% at high flow rates. This could be attributed to thermal gradients in these relatively thick stems excluding the use of this technique for measurements of long term as well as short term water use patterns in older grapevines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004756002983
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Sap flow measurements in grapevines (Vitis vinifera L.) 2. Granier measurements (1999)
    Springer
    Plant and soil 215 (1999), S. 47-55 
    Details
    ISSN: 1573-5036
    Keywords: Huber value ; Granier method ; modelling ; sap flux density ; Vitis ; water use ; xylem flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Granier-system, a relatively simple and continuous method for measuring sap flux density, has been adapted and evaluated for its use in older, mature grapevines. The original calibration of Granier (1985, Annales Sciences Forestieres, 42, 193-200) could be extended to a sap flux density of up to 400 10-6 m3 m-2 s-1 with only little error at high flux densities. A time lag of around 20 min was apparent between transpiration and calculated sap flow which was attributed to the thermal mass of the sensors themselves. The time lag and the consequently dampened response of the system caused a very low accuracy over short time periods thus reducing the value for detailed plant physiological investigations. However, when integrating over longer time intervals, much of the error cancelled out. For daily values the maximum error was within ±10% and after a period of 89 days only 1.5% error remained. This method is thus best suited for long term measurements of total water use.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004708119821
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...