
TY  - JOUR
A1  - Legge, NJ 
A1  - Connor, DJ 
T1  - Hydraulic Characteristics of Mountain Ash (<I>Eucalyptus regnans</I> F. Muell.) Derived From <I>in situ</I> Measurements of Stem Water Potential
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1985
VL  - 12
IS  - 1
SP  - 77
EP  - 88
KW  - 
UR  - https://doi.org/10.1071/PP9850077 
N2  - An osmotic tensiometer has been successfully used for in situ measurements of stem water potential, &#936;st, in mountain ash. During spring and early summer when soils were saturated, fluctuations in &#936;st, at a given height in different trees were very similar. When &#936;st, values were measured at different positions around the circumference of individual trees during late summer, considerable variation between the different positions was recorded. The data at this time also suggest that night temperatures above 17&#176;C can lead to stomatal opening, but this was not confirmed by direct measurement. Possible reasons for apparent discrepancies between leaf and stem water potential measurements are discussed. The time lag between vapour pressure deficit and &#936;st was around 2 h when&#936;st values were high, but fell to 10 min or less for &#936;st values below about - 1.2 MPa. Analysing this time lag in terms of a resistance-capacitance model of water flow made it possible to estimate the storage-to-vessel transfer resistance as 1.7 &#215; 107 Pa s m3 kg-1. 
ER  -

