CAM (Crassulacean Acid Metabolism)pathway.pptx

The Crassulacean Acid Metabolism (CAM) pathway is a photosynthetic adaptation employed by certain plants to optimize carbon dioxide uptake and minimize water loss. This unique physiological strategy allows plants to thrive in arid and semi-arid environments where water availability is limited. The CAM pathway exhibits distinctive features that set it apart from the more common C3 and C4 photosynthetic pathways. In this comprehensive exploration, we will delve into the intricacies of the CAM pathway, its evolutionary significance, molecular mechanisms, ecological implications, and potential applications in agriculture and climate change mitigation.

I. Introduction
A. Background
The CAM pathway is a specialized form of photosynthesis that enables plants to fix carbon dioxide during the night, reducing water loss through transpiration during the day. Discovered in the early 20th century, this pathway has since captivated the interest of scientists due to its ecological and physiological implications.

B. Importance of Photosynthesis
Understanding the various photosynthetic pathways is crucial for appreciating the diversity of plant adaptations and their ecological success. Photosynthesis is the fundamental process by which plants convert solar energy into chemical energy, supporting life on Earth.

II. The CAM Pathway: An Overview
A. General Characteristics
Nocturnal CO2 Fixation
Diurnal Stomatal Opening
Succulent Tissues
Evolutionary Advantage in Arid Environments
B. Comparison with C3 and C4 Pathways
C3 Photosynthesis
C4 Photosynthesis
CAM vs. C3 and C4: Advantages and Disadvantages
III. Evolutionary History of CAM Plants
A. Phylogenetic Distribution
Diverse Plant Families
Evolutionary Constraints and Opportunities
B. Adaptive Evolution
Selection Pressure in Arid Environments
Co-evolution with Abiotic Factors
IV. Molecular Mechanisms of the CAM Pathway
A. Anatomical Adaptations
Leaf Morphology
Stomatal Behavior
Water Storage
B. Biochemical Pathways
Carboxylation and Decarboxylation Reactions
Enzymatic Involvement
Regulation of Metabolic Processes
V. Environmental Influences on CAM Expression
A. Light Availability
Photoperiodic Control
Influence of Artificial Light
B. Temperature
Thermal Adaptations
Impact on Metabolic Rate
C. Water Availability
Drought Stress Responses
CAM as a Water-Saving Strategy
VI. Ecological Implications
A. Habitat Diversity
CAM Plants in Desert Ecosystems
Other Environments Supporting CAM Adaptations
B. Ecological Interactions
CAM-Associated Symbiotic Relationships
Competition with Non-CAM Plants
VII. Applications of CAM Plants in Agriculture
A. Drought-Resistant Crops
Engineering CAM Traits in C3 and C4 Plants
Potential for Crop Improvement
B. Bioenergy Production
CAM Plants as Bioenergy Feedstocks
Challenges and Opportunities
VIII. CAM and Climate Change Mitigation
A. Carbon Sequestration
Potential of CAM Plants in Carbon Capture
Afforestation and Reforestation Initiatives
B. Alleviating Water Scarcity
CAM as a Sustainab

1. CAM ( Crassulacean Acid Metabolism)

2. CAM ( Crassulacean Acid Metabolism) First discovered in plants belonging to the family Crassulaceae Plants utilizing this pathway are adapted to survive in extremely dry habitats. They are succulent plants with xerophytic characters Stomata of these plants are scotoactive (remain closed during day time and open during night)

3. CAM pathway 2 Phases Acidification Phase De acidification Phase

4. Acidification Phase CO 2 enters the leaf through stomata Carbohydrate synthesized during day time, enters the glycolytic pathway and converted into PEP

5. Malic acid accumulates in cell vacuoles increasing intracellular acidity. This may be called acidification of cells

6. Deacidification Phase During day time stomata remain closed, preventing the entry of CO 2 into the leaf and the escape of H 2 O from the leaf. Malic acid is retrieved from the vacuole It undergoes decarboxylation by malic acid decarboxylase enzyme forming pyruvic acid and CO 2

7. Pyruvic acid may enter TCA cycle or get reduced to triose phosphate which in turn converted back to glucose. This results in the decrease in acid level and thereby intracellular acidity is removed. This may be called de acidification of cells.

8. CO 2 produced during de acidification phase enters the C 3 pathway and contribute to the synthesis of sugar