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This comprehensive guide delves into the intricate relationships between photosynthesis, environmental factors, and plant adaptations. Covering topics such as photosynthetically active radiation, light compensation points, photorespiration, C4 and CAM photosynthesis, and habitat preferences, the text provides valuable insights into how plants respond to varying conditions in their quest for optimal growth and survival. Through a detailed exploration of sun and shade leaves, readers will gain a deeper understanding of the strategies plants employ to maximize energy capture and utilization. Whether you are a student, researcher, or nature enthusiast, this resource offers valuable knowledge on the fascinating world of plant photosynthesis.
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Photosynthetically Active Radiation (PAR)
The Light Compensation Point PPFD = Photosynthetic Photon Flux Density
Three Forest Understory Herbs Summer-green: Viola pubescens Spring ephemeral: Allium tricoccum Semi-evergreen: Tiarella cordifolia
Light Compensation Points
Maximum Photosynthetic Rates
Photorespiration: A curious bottleneck in C3 Photosynthesis
Key enzyme 3-carbon compound Catalysis of carbon fixation in Photosynthesis
Photosynthesis • Photorespiration Photorespiration: An alternate pathway Rubisco catalyzes two competing reactions: Rubisco
Ecological Factors Increasing Photorespiration Rates High temperatures Rubisco Low CO2 concentrations
C4 Photosynthesis: A Solution in Space C4 Grass C3 reactions in bundle sheath C3 Grass C3 reactions throughout
C4 Intermediates produced in low CO2 environment of mesophyll (1000 02 : 1 CO2 ) C4 Photosynthesis: A Solution in Space • CO2 concentrated in bundle sheath (100 02 : 1 CO2 )
Differential Response of C4 and C3 Plants Light response Temperature response
CAM Photosynthesis: A Solution in Time CO2 Capture by Night Photosynthesis by Day
Distribution Patterns of the Three Photosynthesis Types
Geographic Patterns in the Distribution of the Proportion of C4 Grasses
C3 – Cool Season Grasses C4 – Warm Season Grasses • Lower temperatures • Lower total rainfall • Higher winter rains • Higher temperatures • Higher total rainfall • Higher summer rains
Habitats Favoring CAM Plants Epiphytes – Plants using other plants for support Arid habitats – deserts and semi-deserts that aren’t too extremely dry
Ecology of Photosythesis Part II
Sun and Shade Leaves Shade Sun
Anatomy of Sun and Shade Leaves (Thermopsis montana): a general view Sun Leaf Shade Leaf • Smaller • Thicker • More rubisco • More chlorophyll • Bigger • Thinner • Less rubisco • Less chlorophyll
Sun and Shade Leaves: Response to Light (Fagus sylvaticus)