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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
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Photosynthesis Carbon Partitioning 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 ← sun ← ground H 2O Calvin cycle ← air CO2
•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 CO2 menjadi CH2O
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Simple equation : 6CO2 + 12H20 + light energy C6H12O6 + 6O2 + 6H2O
Light energy
ECOSYSTEM
Photosynthesis in chloroplasts CO2 + H2O
Organic molecules + O2
Cellular respiration in mitochondria
ATP powers most cellular work
Heat energy
Types of Photosynthesis
Energi mengalir ke dalam suatu ekosistem sebagai cahaya matahari dan meninggalkannya dalam bentuk panas
C3 plants The
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C3 photosynthesis – Most plants
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C4 photosynthesis – A variety of plants, especially our summer annuals and many of our grasses
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CAM photosynthesis Cacti, agaves, bromeliads, and others
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
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wastes carbon fixed by photosynthesis - up to 50% of carbon fixed in photosynthesis may be used in photorespiration
sugar cane
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
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CAM (Crassulacean Acid Metabolism) plants 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)
separate carbon fixation from Calvin cycle by time close stomates during day open stomates during night
at night, open stomates & fix carbon in “storage” compounds
in day, close stomates & release CO2 from “storage” compounds to Calvin cycle
succulents, pineapple, cactuses, agaves, bromeliads
organic acids: malic acid, isocitric acid
increases concentration of CO2 in cells
CAM plants
how plant distributes the carbon compounds derived from photosynthesis and allocates them to different physiological processes and plant parts
Transpiration
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the continual flow of water from the soil, into the roots, up the stem to the leaves, and out of the leaves through the stomata Water moving between soil and plants flows down a water potential gradient
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Plant’s Place in the Environment - Each species occupies a particular place in the ecosystem, known as the habitat - within its habitat, the species carries out a particular ecological role or function, known as the ecological niche of that species
Triggered Responses
to Factors of the Environment Setiap fase perkembangan tanaman melibatkan respon perubahan secara fisiologis. Sebagian besar respon tanaman berkaitan langsung dengan kondisi lingkungan - Triggered Responses - Dependent Responses - Independent Responses
Responses
respon tanaman yang dipacu oleh adanya eksternal stimulus tertentu Dependent
Responses
respon tanaman yang tergantung pada keberadaan kondisi lingkungan eksternal tertentu secara terus menerus Independent
Responses
respon tanaman yang ditentukan oleh kondisi fisiologis tanaman; mis: tanaman jagung akan berbunga karena fase tertentu dari pertumbuhan dan perkembangan sudah tercapai.
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Limits
and Tolerances Each environmental factor has both minimum and maximum levels, tolerance limits, beyond which a particular species cannot survive
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Buat tulisan lengkap tentang tipe fotosintesis Buat tulisan tentang kebutuhan unsur hara yang dibutuhkan tanaman
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