Premium
Further Evidence for the Relative Immobility of Water in Sieve Tubes of Willow
Author(s) -
Peel A. J.
Publication year - 1970
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1970.tb06459.x
Subject(s) - willow , sieve tube element , honeydew , girdling , sieve (category theory) , chemistry , botany , exudate , chromatography , zoology , horticulture , biology , phloem , mathematics , combinatorics
Gradients of tritiated water, 35 S‐sulphate and 32 P‐phosphate, were established in isolated segments of willow stems. Sieve tube exudate was collected as honeydew from the high activity end of the segment. After girdling the stem a few centimetres from the site of sieve tube puncture, the specific activity of 35 S and 32 P in the honeydew rose, whilst the specific activity of tritium remained constant. These findings indicate that prior to girdling, unlabelled sulphates and phosphates were contributing to the honeydew, whilst there had been no detectable contribution by unlabelled water from the low activity end of the segment. The data support the conclusions drawn from previous experiments by Peel et al. (1969), that water is relatively immobile in sieve tubes of willow when compared to solutes.