Transcript Photosynthesis - Prince of Songkla University

Photosynthesis
• What is it ?
• Where it occurs ?
• How ?
• How is its important ?
• How to measure ?
Photosynthesis ประกอบด ้วย 3
กระบวนการย่อย
• CO2 diffusion
A = Cg d[CO2]
• Photochemical process (light reaction)
4H2O + 2ADP+2NADP+ +2pi
O2+2H2O+2ATP+2NADPH +2H+
• Biochemical process
3CO2+9ATP+6NADPH+6H+
P+6NADP+9ADP+8Pi+3H2O
triose-
The overall chemical reaction
• CO2 + 2H2O
H2O
light / atenna
ADP +Pi +NADP+
CO2
(CH2O) + H2O + O2
PSII PSI Cytochrome
enzymes/ stroma
RuBPcarboxylase : CO2receptor
O2 + H+ +Pi
ATP + NADPH
(CH2O)
CHLOROPLAST
• 1- 10 mm
• Lamellae (membranes) : light reaction
– stroma lamella (double lamella)
– grana lamella (stacked lamella)
• Stroma : dark reaction
Leaf anatomy of C3 vs. C4 plants
Chloroplast and
Chlorophyll structure
Electron transportation
• Chlorophyll a ,b Carotenoid
• Reaction centers : absorbed PHOTONS
from light energy
• PSII : ground stage
excited stage
• PSI : Q , Photophosphorylation
Energy diagram of the photosynthetic
electron transport system
Light
Light
O2
Chlorophyll a/b
Chlorophyll a
P680 Electron transfer
P700 Electron transfer
NADPH
ATP
H2O
Photosystem II
Photosystem I
Energy diagram of the photosynthetic electron transport
Redox potential
Fd-Ub
-800
e-
-600
NADP+
Fd
-400
-200
Q
0
200
Solar eradiation
Solar
radiation e ADP
e-
Cty f
400
ATP
600
800
H2O
Photo
system II
H+
O2
NADPH
Photo
system I
CO2
reduction
Radiation vs Photons
• E = hv = speed of light/wave length
• E = energy content of the quantum (J/quantum)
• h = Planck ‘s constant (6.626 x 10-34 J s)
400 500
25
20
7.5
6
5
4
600 700 (nm)
16.7 14.3 (x103 cm-1)
5
4.5 (x1014 s-1)
3.3 2.9 (x10-19 J quantum-1)
Conversion factors for energy units
used in the text
•
•
•
•
•
•
•
•
•
•
=
1.602 x 10-19 J
=
1 J s-1
=
3.6 x 106 J
=
0.239 calories
=
6.242 x 1018 eV
1 cal.
=
4.184 J
1 kJ mol quantum -1
=
1.036 x 10-2 eV
Plank’s constant
=
6.62 x 10-34 Js
=
4.136 x 10-15 eVs
1 mol quantum of photon contains Avogadro’s number
6.023 x 1023 particles =
1 Eistein
1 electron volt (eV)
1 watt
1 kWh
1 Joule
Radiation & Light
Carbondioxide fixation
Biomass or Dry weight = Photosynthesis Respiration - Dead - Translocation
Carbon Balance
• C3 species : Calvin cycle ; RUBP
3-PGA
• C4 species : Hatch & Slack cycle ;
PEP
Oxaloacetic Acid etc.
• Crussulation Acid Metabolism (CAM) : CO2
fixed during night
C3 vs C4 : Kranz anatomy
C3 C4 and CAM plant
PEP Carboxylase
CO2
C4 Organic acids
RuBP Carboxylase
CO2
CO2
PGA
RUBP
PEP
C3
C4
CAM
C3 acids
Mesophyll
Mesophyll
Bundle sheath
Dark
Light
(CH2O)
พืช C3 vs C4
• ลักษณะทางกายภาพต่างกัน C3 ไม่มV
ี ascular
sheath แต่ C4 มี (Kranz anatomy)
• เอนไซม ์ PEPase มีความสามารถจับ CO2 ดีกว่า
เอนไซม ์ RUBPase
• C4 มีอ ัตราการสังเคราะห ์แสงสู งกว่า C3 (ใน
สภาพแสงจัด)
• C4 ใช้พลังงานมากกว่า C3 ในการตรึง CO2 1
โมเลกุล
• C4 มี RUBP น้อยกว่า C3
้
้ และ ร ้อนชืน
• C3 ปร ับตัวได้ดใี นสภาพ เย็นชืน
้
ส่วน C4 ปร ับต ัวได้ดใี นสภาพ ร ้อน แห้ง หรือ ชืน
Cellular respiration
• The process by which active cells obtain
energy. It occurs in mitochondria, there are two
coditions : aerobic & anaerobic respiration.
• The obtained energy was used for maintenance
and growth of the cell or organ.
• Growth respiration : catabolism provides the
energy required for biosynthesis and
constructive reactions leading to form cellular
products used in the crop growth
Aerobic respiration has 3 stages :
C6H12O6 + 6O2
6CO2 + 6H2O + energy
Sucrose
NAD+
Glycolysis
Pyruvic
acid
e transport
chain
TCA
NADH,
ATP
2
Oxidative
phosphorylation
Krebs’ cycle
NADH
NADH+,
ADP
O
H2O
Respiration
• MITOCHONDRIA
• C6H12O6 + 6O2
6CO2 + 6H2O +637 kcal
• Glycolysis : anaerobic respiration
• aerobic respiration : Krebs cycle ; Oxidative
phosphorylation
• Electron transport chain : ATP, NADPH formed
and available for other synthesis of other
moplecules for growth, active transport, and
metabolic processes.
Major plant metabolisms
O2
STRUCTURAL
compounds
• cellulose
• hemicellulose
• pentosans
• pectin, ect.
STORAGE
compounds
• starch
• fructosans
• proteins
• lipids, ect.
ACTIVE CELL
compounds
• nucleic acids
• enzymes
• cytochrome
• chlorophyll
• phospholipids,
ect.
Chloroplast : Photosynthesis
Synthesis / Translocation
Glycolysis
CO2
ATP,
NADP
Mitochondria : Respiration; Krebs cycle
O2
CO2
Photosynthesis vs Respiration
• Photophosporylation
• Oxidative phosphorylation
• NADPH formed
• NADP formed
• CO2 reduction
• O2 reduction
• CO2 as substrate
• CO2 is product
• H2O as substrate
• H2O is product
• O2 is product
• O2 is substrate
• CH2O is product
• (CH2O)n is substrate and
product
Photosynthesis vs
Respiration if …….
•
Down
• Up
if + O2
•
Up
• Down
if + CO2
•
Up
• Up
if + light
•
Up
• Up
if + temperature
•
Stop
• Burst
if dark
่ อทีใช
่ ้วัดการสังเคราะห ์ด ้วยแสง
เครืองมื
Ce
Reference
IRGA
Analyser
Co
ระบบเปด
Data logger
Environments
SOIL
CLIMATE
AGRONOMY
Character of CROPS
Water route
Photosynthesis
Yield potential
Etr/Etm
Pst
Pst * Etr/Etm -Res
P pot X HI
BAMnut model
(Azam-Ali Sayed et.al, 2001. A Global Mapping Systems for Bambara Groundnut
Production. FAO Agricultural Information Management Series)
Water
limited
growth
(WLG)
Weather data
seed
Water uptake
Radiation
limited
growth (LLG)
Bambara groundnutIntercepted radia
Soil water
Root
PodW
Leaf
LeafW
RootW
ShootW