PLANTS AND ENVIRONMENTAL FACTORS

1. PLANTS AND ENVIRONMENTAL FACTORS

2. 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

3. THE PLANT • Photosynthesis • Carbon Partitioning • Transpiration

4. 1. Photosynthesis “Plants convert solar energy into chemical energy stored in the chemical bonds of sugar molecules” this process is IMPORTANT for plant growth and survival

5. Remember what plants need… • Photosynthesis • light reactions • light • H2O • Calvin cycle • CO2  sun air  ground

6. 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

7. Simple equation : 6CO2 + 12H20 + light energy C6H12O6 + 6O2 + 6H2O

8. Light energy ECOSYSTEM Photosynthesisin chloroplasts Organicmolecules CO2 + H2O + O2 Cellular respirationin mitochondria ATP powers most cellular work Heatenergy Energi mengalir ke dalam suatu ekosistem sebagai cahaya matahari dan meninggalkannya dalam bentuk panas

9. Types 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

10. C3 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

11. C4 plants • A better way to capture CO2 • 1st step before Calvin cycle, fix carbon with enzymePEP carboxylase • store as 4C compound • adaptation to hot, dry climates • have to close stomates a lot • different leaf anatomy • sugar cane, corn, other grasses…

12. sugar cane corn

13. 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)

14. CAM (Crassulacean Acid Metabolism) plants • 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 • organic acids: malic acid, isocitric acid • in day, close stomates & release CO2 from “storage” compounds to Calvin cycle • increases concentration of CO2 in cells • succulents, pineapple, cactuses, agaves, bromeliads

15. CAM plants

16. 2. Carbon Partitioning how plant distributes the carbon compounds derived from photosynthesis and allocates them to different physiological processes and plant parts

18. THE PLANT Transpiration

19. 3. Transpiration 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

20. Water movement between plants and soils

21. Transpiration

22. The Plant in its Interaction with The 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

23. The Plant in its Interaction with The Environment • Responses to Factors of the Environment Setiapfaseperkembangantanamanmelibatkanresponperubahansecarafisiologis. Sebagianbesarrespontanamanberkaitanlangsungdengankondisilingkungan - Triggered Responses - Dependent Responses - Independent Responses

24. Triggered Responses respontanaman yang dipacuolehadanyaeksternal stimulus tertentu • Dependent Responses respontanaman yang tergantungpadakeberadaankondisilingkunganeksternaltertentusecaraterusmenerus • Independent Responses respontanaman yang ditentukanolehkondisifisiologistanaman; mis: tanamanjagungakanberbungakarenafasetertentudaripertumbuhandanperkembangansudahtercapai.

25. The Plant in its Interaction with The Environment • Limits and Tolerances Each environmental factor has both minimum and maximum levels, tolerance limits, beyond which a particular species cannot survive

27. Tugas Buat tulisan lengkap tentang tipe fotosintesis Batasan cahaya matahari yang dapat dimanfaatkan tanaman untuk fotosintesis Bagaimana adaptasi tanaman terhadap kelebihan dan kekurangan cahaya?