Question

Скорость фотосинтеза зависит от лимитирующих (ограничивающих) факторов, среди которых выделяют свет, концентрацию углекислого газа, температуру. Почему эти факторы являются лимитирующими для реакций фотосинтеза?

Answer 1

лимитирующий фактор-это любой ограничив экологический фактор, показатели которого как-либо ограничивают жизнедеятельность организма. 1) свет необходим для возбуждения хлорофтла так постаавляется энергия для процесса фотосинтеза2) СО2 неоюходим в темновой фазе фотосинтеза, из него синтезируетя глюкоза.

Answer 2

Factors Limiting Photosynthesis

The speed or rate of photosynthesis is influenced by several limiting factors, including light intensity, carbon dioxide concentration, and temperature. These factors are crucial for the reactions involved in photosynthesis to occur efficiently.

1. Light Intensity: Light is essential for photosynthesis as it provides the energy needed to convert carbon dioxide and water into glucose and oxygen. However, the rate of photosynthesis can be limited if the light intensity is too low. In low light conditions, the production of ATP and NADPH, which are essential for the light-dependent reactions, may be insufficient, leading to a decrease in the overall photosynthetic rate.

2. Carbon Dioxide Concentration: Carbon dioxide is another critical factor that can limit photosynthesis. It is the source of carbon atoms used to build glucose molecules during the light-independent reactions. When the concentration of carbon dioxide is low, the rate of photosynthesis can be reduced because there is not enough carbon available for the synthesis of glucose. Increasing the carbon dioxide concentration can enhance the photosynthetic rate up to a certain point, after which other factors may become limiting.

3. Temperature: Temperature plays a crucial role in photosynthesis because it affects the activity of enzymes involved in the process. Enzymes have an optimal temperature range at which they function most efficiently. If the temperature is too low, enzyme activity decreases, slowing down the photosynthetic rate. On the other hand, if the temperature is too high, enzymes can denature, leading to a decrease in photosynthesis. Different plant species have different temperature optima for photosynthesis, but generally, temperatures between 20-30°C are favorable for most plants.

It is important to note that these factors can interact with each other and have complex relationships. For example, if light intensity is low, increasing the carbon dioxide concentration may not significantly increase the photosynthetic rate because the light-dependent reactions are already limited by the low light intensity. Similarly, if the temperature is too high, increasing the carbon dioxide concentration may not have a significant effect on photosynthesis because the enzymes involved may already be denatured.

In summary, light intensity, carbon dioxide concentration, and temperature are limiting factors for photosynthesis because they directly affect the availability of energy, carbon, and the activity of enzymes involved in the process. Understanding and optimizing these factors are crucial for maximizing photosynthetic efficiency in plants.