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The secret defense of photosynthesis: How do plants protect against damage from excessive sunlight?
With the impact of global warming and climate change, plants are facing increasingly severe challenges in adapting to environmental changes. Although excessive sunlight is an important source of life, for many plants, too much light can be harmful. Since ancient times, plants have developed a series of photoprotection mechanisms to resist these potential dangers, which can effectively reduce cell damage during photosynthesis and promote growth.
Excessive sunlight exposure may lead to photoinhibition, or photoinactivation of reaction centers, which does not necessarily involve chemical damage.
In organisms that perform oxygenic photosynthesis, if the light intensity is too high, it may cause unproductive reactions of photosynthetic pigments such as chlorophyll, thereby generating reactive oxygen species (ROS) that damage the plant. The production of such ROS is particularly evident under extreme environments and high light intensities, further posing challenges to plants.
Therefore, plants must possess a series of photoprotection mechanisms, including non-photochemical quenching mechanisms such as flavonoid cycle and structural reorganization. These mechanisms work together to reduce damage to the photosynthetic system and ensure healthy plant growth.
In plants, certain photoreceptors detect the intensity, direction, and duration of light and adjust the arrangement of chloroplasts to reduce photodamage.
Even more interesting is that some plants use pigment changes as a form of photoprotection under high light intensities. In the Antarctic, the color difference between red and green mosses shows how these plants respond to light intensity. The change in color is not only related to the intensity of light, but also to the light perception system of these plants.
Recently, researchers conducted an experiment to analyze the photoprotective capacity of Antarctic moss UV-absorbing compounds (UVAC) and red pigments against high light intensities. The experiment found that red mosses performed better in environments with high light intensity because their red pigments and high concentrations of UVAC in their cell walls effectively reduced light damage.
The production of UV-absorbing compounds and red pigments increased in tandem with high light intensities, demonstrating the plant's high adaptability to light intensity.
Although we have gained a lot of understanding of the photoprotection mechanisms of plants, with the rapid changes in the global climate, can we fully realize the importance of these mechanisms and protect them?
Human photoprotection mechanisms
In addition to plants, other organisms also carry out different photoprotection mechanisms, such as the process of converting DNA, proteins and melanin inside human skin. This internal conversion can effectively convert the absorbed UV light energy into heat energy, avoiding damage to DNA and other cell tissues. In addition, with the development of the cosmetics industry, various sunscreens have appeared on the market, which claim to be similar "artificial melanin" and are intended to protect the skin from UV damage.
However, the long-term effects of artificial sunscreen ingredients and their actual effectiveness are still under further study. This also raises questions about artificial photoprotectants and how they compare to natural biological mechanisms, especially in the face of increasingly dangerous ultraviolet rays.
Our understanding of the photoprotection mechanisms of plants and humans is far from sufficient, and this may be an important topic for future biological research.
The research on photosynthesis and photoprotection mechanisms is not only of great significance to agricultural development, but will also play a positive role in promoting environmental protection and biodiversity conservation. These explorations will help us gain a deeper understanding of how nature works and seek harmonious coexistence between organisms and the environment. Can we draw inspiration from this to create a more sustainable future?
