218
(b)
- c:: Q)
- c::
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u
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Q)
- ctS
==
Q)
>
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ctS
Q)
a::
(a)
,....
'(I)
C\I
E
o
E
0>
cD
U
c::
~ :::J
"0
c::
o
()
0.88
0.84
0.80
0.5
0.4
0.3
0.2
0.1
14.9
25.3
.........
30.6 ... ...
•
..
........
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...
..... ::::::: ..
31.8
.... ::::::::: ....
...
5
4
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. ........ .
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'0
•••••••
--I.R. Cowan
--:::::"
"<:;;;;;;;;;;;;;;;;; ,; ,; . . . . . : . : . : : . . . . . . ..
... :::.:.:~>;;;;:: . . . #
'./
3
2
o
Transpiration rate, E mmol m- 2 s-1
Increasing water potential 'P
Fig. 10.4. Data of Schulze et al. (see Fig. 10.1) rearranged to show dependence of
conductance, g, and relative water content, W, on rate of transpiration, E. Humidity
differences between leaf and air, 8, are represented as the inverse slope of the straight
lines. The lower abscissa indicates the presumed effect of rate of transpiration on water
potential in the guard cells of the stomata, 'I'