leaves opposite to cluster - offerta formativa...3 adp + 3 pi . grapevine photosynthesis vs....
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Fotosintesi
Energia solare
(8 FOTONI )
PIGMENTI
PIGMENTI
ECCITATI
2 NADPH2
2 NADP
CO2
O2
2 H2O CH2O + H2O
FASE FOTOCHIMICA
TRASFERIMENTO DI ELETTRONI E FORMAZIONE
DI ATP
FASE BIOCHIMICA
3 ATP
3 ADP + 3 Pi
Grapevine photosynthesis vs. environmental,
physiological and cultural factors
• Phenological stage measurements are made
• Environmental conditions during readings
• Equipment available
• Units (1 µmol CO2 m
-2 s-1 = 0.63 CO2 mg dm-2 h-1)
Radiation
• Light response curve
• Light environment during leaf development
• Light environment after leaf development
100 % Incident
6% reflected
85% absorbed
9% transmitted
Leaf
Pn
PAR (µmol m-2 s-1)
(µmol m-2 s-1)
0 400 800 1200 1600 2000
0
2
4
6
8
10
12
Light saturation point
Light compensation point
Pn max
Quantum
yield
Pn
PAR (µmol m-2 s-1)
(µmol m-2 s-1)
0 400 800 1200 1600 2000
0
2
4
6
8
10
12
External canopy layer
(it gets 1600 µmol m-2 s-1)
2° layer (160 µmol m-2 s-1, 10% of 1600)
3° layer (16 µmol m-2 s-1, 10% of 160)
Comparison of single leaf and whole-canopy assimilation
(A) rates.
Vine 1
Vine 2
LA (m2)
1.26
1.34
Al (µmol m-2 s-1)
Ac (µmol m-2 s-1)
9.3 1.3
8.3 0.7
8.7 0.8
8.0 0.7
4.5 0.1
4.1 0.1
4.0 0.1
3.8 0.1
Morn. Aft. Morn. Aft.
-2 -1
Single leaf
Free growing canopy
Constrained canopy
0 250 500 750 1000 1250 1750 1500 2000
Pn (µmol m s )
0
2
4
6
8
10
12
14
16
PFD (µmol m s ) -2 -1
- 48%
- 26%
Taken from Intrieri et al.
Vitis (1997) 36: 167-173
Total Specific (µmol s-1)
Another good example…..
Leaf area per vine (m2) Leaf area per vine (m2)
(µmol m-2 s-1)
0 300 600 900 1200 1500 1800 PAR (µmol m-2 s-1)
Pn (µmol m-2 s-1)
0
2
4
6
8
10
12
«sun» leaves
«shade» leaves
Sun leaves
R:FR = 0.40
PFD = 90% max
(1600 µmol m-2 s-1)
PFD = 8% max
(150-200 µmol m-2 s-1) PFD = 90% max
Sun leaves then shaded
Pn
PFD (µmol m-2 s-1)
(µmol m-2 s-1)
58 gg
82 gg
113 gg
(17 d of shade)
(41 d of shade)
(72 d of shade)
Leaf age
cv. Sangiovese
0 400 800 1200 1600 2000
0
2
4
6
8
10
1
2
Sun leaves always in the sun
58 d 82 d 113 d
Pn (µmol m-2 s-1)
Leaf age
PFD (µmol m-2 s-1)
cv. Sangiovese
0
2
4
6
8
10
12
0 400 800 1200 1600 200
0 Da Silvestroni et al., 1993
Temperature • Long term effects
• Short term effects
Pn and other factors • Diurnal variation • Seasonal variation • Leaf age • Compensation mechanisms • Source and sink balance
WCE
PAR
VPD
4 6 8 10 12 14 16 18 20 Solar time (h)
Gobelet P
AR
(µ
mo
l m
-2 s
-1)
VP
D (
kP
a)
WC
E (
mm
ol
s-1)
WCA
WCE
WUE
6 8 10 12 14 16 18 20 Solar time (h)
Gobelet
WC
E (
µm
ol
s-1);
WU
E (
WC
A/W
CE
)
WC
A (
µm
ol
s-1)
4
Leaf age (days)
Pn
(µ
mo
l m
s
)
0 20 40 60 80 100 120 140 160 180 0
1
2
3
4
5
6
7
8
9 10
11
12
0
5
10
15
20
25
30
35 -2
-1
Fully
expanded
leaf
-2
-1
Sultana, lab, Kriedemann,
1970
Sangiovese, pots- outdoor,
Intrieri et al. 1992)
Sangiovese, field, Poni
et al. 1994
Pn
(m
g d
m
h
)
Leaf position on shoot stem
0 4 8 12 16 20 24 28 32 36 40 44 0
2
4
6
8
10
12
14
16 May 19 June 23 July
(31 days) P
n (
µm
ol
m-2
s-1
)
Leaf position on shoot stem
0 4 8 12 16 20 24 28 30 36 40 44 48 52 56 60 0
2
4
6
8
10
12
14
Shoot apex
21 September
26 October
Pn
(µ
mo
l m
-2 s
-1)
bloom
veraison harvest
May June July Aug Sept Oct
a
a a
a a
a a
a a
a
a
a
b
b
b
b
b
b b
b
b b
b
b
c
c
c
c
c
ns
a
a
a
basal median apical P
n (
µm
ol
m-2
s-1
)
Leaf age (days)
Pn (µmol m-2 s-1) Chlorophill (mg/dm2)
0 20 40 60 80 100 120 140 160 180 0
2
4
6
8
10
12
0
0.5
1
1.5
2
2.5
3
3.5
2 SE
Leaf age (days)
Pn (µmol m-2 s-1) N (mg/cm2)
0 20 40 60 80 100 120 140 160 180 0
2
4
6
8
10
12
0
0.05
0.1
0.15
0.2
2 SE
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