OBT Formation in Darkness of
Photosynthesis
is based one re-valuation of
ONTARIO HYDRO Report No 84-69-K
(1984) by F. S. Spencer
Tritiated Water Uptake Kinetics in TissueFree Water and Organically Bound Fractions
of Tomato Plants.
9 Weeks HTO exposure ,16 hours illumination, 8 hours darkness
OBT Data of Tomato Plants During 9 Weeks of HTOExposure
35.000
30.000
OBT[pCi/gH]
25.000
20.000
15.000
10.000
5.000
0
0
7d
14d
21d
28d
35d
168
336
504
672
840
42d
49d
56d
63d
1008 1176 1344 1512
Hours HTO Exposure
The Method of Graphical Analysis
Biological formation and mono-molecular kinetics start exponential according to
F(t) = A*2
to **t/τ
F(t) = A*(1−2−(t−to)/τ) = A − C* 2−t/τ
F(t) = A*2**t/τ and terminate according
Both, in biological product formation and in mono-molecular reactions exist a
self-accelerating and a
self-inhibiting phase
A
OBT = A*(1-2–(t-to)/τ)
= A – C*2t/τ
Product
Selfaccelerating
phase
Selfinhibiting
phase
OBT = B*2t/τ
Formation Time
The OBT Data of Tomato Plants During 9 Weeks of
35.000
HTOExposure
2 OBT Pathways to OBT by H+/T+ Exchange
30.000
OBT [pCi/gH]
25.000
2 inhibiting phases !
Late
T+/H+ Exch
Late H+/T+ exchange
self- inhibiting
Phase
20.000
Late H+/T+ exchange
self- accelerating
15.000
1 Pathway to CBT Phase
by Photosynthesis
10.000
Photosynthesis
5.000
+/T
++
+/H
Early
HT
exchange
Early
14d 21d
28d
7d
35d 42d
0
0
168
336
504
672
840
49d
56d
63d
A look at details of
700 h growth
1008 1176 1344 1512
Hours HTO Exposure
10.000
9.000
8.000
Dark phases during photosynthesis
OBT[pCi/gH]
7.000
Photosynthesis
inhibiting
phase
6.000
5.000
Late H+/T+
4.000
3.000
Early H+/T+
2.000
Photosynthesis
accelerating phase
by approximation
1.000
0
0
7d
14d
168
336
Hours HTO Exposure
21d
504
28d
672 at details of
A look
24 h growth
10.000
10.000
10.000
10.000
9.000
9.000
9.000
9.000
8.000
8.000
8.000
8.000
There is no OBT formation
by photosynthesis at night.
But there is OBT formation
at night by
fast H+/T+ exchange
6.000
6.000
5.000
5.000
4.000
4.000
7.000
7.000
6.000
6.000
5.000
5.000
4.000
4.000
TFWT [pCi/mL]
[pCi/mL]
TFWT
OBT[pCi/gH]
OBT[pCi/gH]
7.000
7.000
Fast T+/H+
3.000
3.000
3.000
3.000
2.000
2.000
2.000
2.000
1.000
1.000
1.000
1.000
1d
1d
00
00
24
24
Hours
Hours HTO
HTO Exposure
Exposure
00
Accelerating Accelerating Photosynthetic
Photosynthetic
Phase
Phase
Thank You for
Your Attention
Photosynthetic photon flux density: 500→430 mE/s/m2
Steady‐state atmospheric HTO: 95080±11280 pCi/gH
6 Plants (14‐16 weeks old)
Lower = Old Foliage → abrupt exposure
Upper = New Foliage → chronic exposure
10.000
9.000
8.000
OBT formation during 7 days
OBT[pCi/gH]
7.000
6.000
5.000
4.000
Early T+/H+
3.000
2.000
1.000
0
0
Accelerating
Photo-synthetic phase
During accelererating
Photosynthesis
OBTformation is inferior
to fast H+/T+
1d
2d
3d
24
48
72
4d
5d
6d
7d
96
120
144
168
Hours HTO Exposure
A look at details of
1 day growth