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. Nutritional Needs 4. 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H2O  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

Simple equation : 6CO H light energy C 6 H 12 O 6 + 6O 2 + 6H 2 O

Light energy ECOSYSTEM CO 2 + H 2 O Photosynthesis in chloroplasts Cellular respiration in mitochondria Organic molecules + O 2 ATP powers most cellular work Heat energy Energi mengalir ke dalam suatu ekosistem sebagai cahaya matahari dan meninggalkannya dalam bentuk panas

Types of Photosynthesis C3 photosynthesis –The most widespread type of photosynthesis. –Beans, squash, and tomatoes C4 photosynthesis –Corn, sorghum, and sugarcane CAM (crassulacean acid metabolism) photosynthesis –Cacti, agaves, bromeliads, and others

C3 plants  The first stable compound formed in dark reactions ( Calvin cycle) is 3-carbon compound (glucose)  A problem with C3, photosynthesis is always accompanied by photorespiration which consumes and releases CO 2 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 A better way to capture CO 2 In this system, CO2 is incorporated into 4-carbon compounds before it enters the dark reactions. Then enzymes break loose the extra carbon as CO2. the CO2 is then used to form the 3-carbon compounds used in dark reactions. adaptation to hot, dry climates  Enables photosysthesis accur while stomata are closed

corn sugar cane

 Photorespiration is nearly absent in C4 plants - so greatly increases their efficiency - this is because a high CO 2 : low O 2 concentration limits photorespiration  Thus net photosynthetic rates are higher for C4 plants (corn, sorghum, sugarcane) than in C3 relatives (wheat, rice, rye, oats)

CAM (Crassulacean Acid Metabolism) plants  separate carbon fixation from Calvin cycle by  Keep close stomates during day  open stomates during night  at night, open stomates & fix carbon in “storage” compounds (4-carbon coumpond malate and stored in vacuoles  in day, close stomates & release CO 2 from “storage” compounds to Calvin cycle  CAM plant common in hot and dry environment, they include many succulents, pineapple, cactuses, agaves, bromeliads

CAM plants

how plant distributes the carbon compounds derived from photosynthesis and allocates them to different physiological processes and plant parts

 The carbon compounds produced by photosynthesis play critical role in plant growth and respiration  Humans select plants that shunt more photosynthate to the harvestable part of crop.

 Carbon, hydrogen and oxygen make up approximately 95 % of the average plant’s fresh weight  The elements that make up the other 5 % of living plant matter must come from soil (essensial nutrients)

 Macronutrient : N, P, K and Ca, Mg, S  Micronutrient : Fe, Cu, Zn, Mn, Mo, B, and Cl

 needed in large amounts by plant  major component of proteins  required in enzyme synthesis  required in chlorophyll synthesis  adsorbed by plant as NO3- or NH4-

 Important component of nucleic acids, nucleoproteins, phospholipids, ATP  Cell membranes depend on phospholipids  Absorbded as phosphates form through plant roots

 Its involved in osmoregulation (stomatal movement)  As cofactor for many enzyme systems  Needed for cell devission and growth  Linked to cell permeability  Plant show better resistance to disease and environmental stress when potassium supplies are adequate

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

Interaction Plant -Environment  A 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

Interaction Plant -Environment  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

 Triggered 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.

Interaction Plant -Environment  Limits and Tolerances Each environmental factor has both minimum and maximum levels, tolerance limits, beyond which a particular species cannot survive

1. Buat tulisan tentang - fotosintesis - partisi karbon (asimilat) - transpirasi