29/09/2011 1 its about .. An understanding of the ways individual plants and their physiology are impacted by different factors of the environment is an essential component in the design and management of cropping system The ecological study of individual plant response to the diverse factors of environment (autecology or physiological ecology) is a foundation of agroecological understanding 1. Photosynthesis 2. Carbon Partitioning 3. Transpiration “Plants convert solar energy into chemical energy stored in the chemical bonds of sugar molecules” this process is IMPORTANT for plant growth and survival Remember what plants need Photosynthesis light reactions light H 2 O Calvin cycle CO 2 ← sun ← ground ← air •Fotosintesis •Proses dimana organisme yang memiliki kloroplas mengubah energi cahaya matahari menjadi energi kimia •Melibatkan 2 lintasan metabolik •Reaksi terang: mengubah energi matahari menjadi energi seluler •Siklus Calvin: reduksi CO 2 menjadi CH 2 O
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03. PLANTS AND ENVIRONMENT FACTORS - medha … of Photosynthesis • C3 photosynthesis – Most plants • C4 photosynthesis ... Microsoft PowerPoint - 03. PLANTS AND ENVIRONMENT FACTORS
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29/09/2011
1
its about ..
An understanding of the ways individual
plants and their physiology are impacted by
different factors of the environment is an
essential component in the design and
management of cropping system
The ecological study of individual plant
response to the diverse factors of
environment (autecology or physiological
ecology) is a foundation of agroecological
understanding
1. Photosynthesis
2. Carbon Partitioning
3. Transpiration“Plants convert solar energy into chemical
energy stored in the chemical bonds of sugar
molecules”
this process is IMPORTANT for
plant growth and survival
Remember what plants need�
� Photosynthesis
� light reactions
� light
� H2O
� Calvin cycle� CO2
←←←← sun←←←← ground
←←←← air
•Fotosintesis
•Proses dimana organisme
yang memiliki kloroplas
mengubah energi cahaya
matahari menjadi energi
kimia
•Melibatkan 2 lintasan
metabolik
•Reaksi terang: mengubah
energi matahari menjadi
energi seluler
•Siklus Calvin: reduksi CO2menjadi CH2O
29/09/2011
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Simple equation :
6CO2 + 12H20 + light energy
C6H12O6 + 6O2 + 6H2O
Light energy
ECOSYSTEM
CO2 + H2O
Photosynthesis
in chloroplasts
Cellular respiration
in mitochondria
Organic
molecules+ O2
ATP
powers most cellular work
Heat
energy
Energi mengalir ke
dalam suatu
ekosistem sebagai
cahaya matahari dan
meninggalkannya
dalam bentuk panas
Types of PhotosynthesisTypes of Photosynthesis
• C3 photosynthesis
– Most plants
• C4 photosynthesis
– A variety of plants, especially our summer annuals and many of our grasses
• CAM photosynthesis
– Cacti, agaves, bromeliads, and others
C3 plantsC3 plants
� The first stable compound formed in dark reactions (Calvin cycle) is 3-carbon compound
�A problem with C3, photosynthesis is always accompanied by photorespiration which consumes and releases CO2 in the presence of light
� it wastes carbon fixed by photosynthesis - up to 50% of carbon fixed in photosynthesis may be used in photorespiration
C4 plants C4 plants
A better way to capture CO2
• 1st step before Calvin cycle,
fix carbon with enzyme
PEP carboxylase
� store as 4C compound
• adaptation to hot, dry climates
� have to close stomates a lot
� different leaf anatomy
• sugar cane, corn,
other grasses…
corn
sugar cane
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� Photorespiration is nearly absent in C4 plants - so greatly increases their efficiency - this is because a high CO2: low O2 concentration limits photorespiration
� Thus net photosynthetic rates are higher for C4 plants (corn, sorghum, sugarcane) than in C3 relatives (wheat, rice, rye, oats)