238
Q)
Cl
c
co
.c
()
x
w
N
0
()
Q)
...
::J
.... ...
Q)
0.
«
co .... co
E
0
....
CJ)
Cl
a..
>
4.0
~
'7
3.5
(J)
<' ;' I
3.0
E
0
E 2.5
.3- 2.0
1.5
250
200
N~ 150
E 100
.3- 50
0
10
8
'?~
6
E
E1
4
2
0
0
Tradescantia albiflora
,
\
.\
_.-''-...1
60 120 180240 300 360 420
Time [min]
L. Kappen et al.
Fig. 11.6. COz exchange and response of the stomatal apparatus from a green leaf in light
(350j.lmol photons m- z S-1 PAR, temperature 20°C) to changes in VPD and at different
soil water status: weIl-watered ( - and -e-), 7 days slightly and the last 2 days before
the experiment not watered (_.- and -0-). (After Kappen and Haeger 1991)
watered plant cease with increasing stress (Fig. 11.6). A weak oscillation
was seen if the plant was subjected to water stress for 2 days before the
experiment. The oscillation disappeared if the plant was slightly watered for
1 week and then received no water at all 2 days before the experiment
(Kappen and Haeger 1991).
11.4.2 Response to Changing CO2 Concentrations of the Air
If air CO2 concentration was decreased to about half its normal value,
stomata of Vicia faba responded significantly in light (400 !lmol photons