| Factor | Description |
|---|---|
| Light Quality | Photosynthesis primarily uses red (650-700 nm) and blue (400-500 nm) light wavelengths, affecting the efficiency of photosynthesis. |
| Light Intensity | The rate of CO2 fixation increases with light intensity up to a point. Beyond this point, chlorophyll can degrade, reducing photosynthesis. |
| Saturation Point (Light Intensity) | Shade-loving plants reach light saturation at around 10% of full sunlight, while sun-loving plants may require up to 50% of full sunlight. |
| Compensation Point (Light Intensity) | The point at which the rate of photosynthesis equals the rate of respiration; below this point, the plant cannot survive. |
| Carbon Dioxide Concentration | CO2 is a major limiting factor. Increased CO2 concentrations enhance photosynthesis until saturation is reached. |
| Saturation Point (CO2 Concentration) | C3 plants show saturation beyond 450 µl/L (approximately 500 ppm), while C4 plants saturate around 360 µl/L. |
| Compensation Point (CO2 Concentration) | The compensation point for CO2 occurs at low concentrations, below which the plant cannot photosynthesize efficiently. |
| Temperature | Optimal temperature ranges differ among plant types. C4 plants generally have a higher temperature optimum than C3 plants. |
| Water Availability | Water is essential for photosynthesis; however, water stress causes stomatal closure, leading to reduced CO2 uptake. |
| Chlorophyll Destruction | Excessive light intensity can lead to photooxidation, resulting in the breakdown of chlorophyll, thereby reducing photosynthetic efficiency. |
| Photosynthesis/Respiration (P/R) Ratio | The P/R ratio indicates the balance between photosynthesis and respiration. In optimal conditions, the ratio is greater than 1, while in stressful conditions, it may drop below 1. |
| Law of Limiting Factors | The rate of photosynthesis is determined by the most limiting factor; if one factor is insufficient, it restricts the overall process. |
DOSSIER: Photosynthesis, pre-class