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Evidence for Error in Pressure‐Bomb Estimates of Stem Xylem Potentials
Author(s) -
Ritchie Gary A.,
Hinckley Thomas M.
Publication year - 1971
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1937640
Subject(s) - xylem , turgor pressure , pinus contorta , transpiration , hydrostatic pressure , botany , biology , ecology , environmental science , mechanics , physics , photosynthesis
The hydrostatic component of water potential was measured concurrently in stems and needles of five species of conifers (Pinus contorta, P. jeffreyi, Pseudotsuga menziesii, Abies amabilis, and A. procera). In Douglas—fir and the true firs pressure—chamber measurements of potentials were up to 4 bars more negative in stems than in needles. The difference appears to be due to filling of non—vascular xylem tissue with fluid during measurement. This tissue seems to function as a water reservoir, enabling needles to maintain relatively high turgor levels during periods of rapid transpiration.