Researchers at MIT have observed one of the possible mechanisms by which Plants are able to dissipate excess sunlight absorbed by the plants.
What is the research aimed at?
- It was known that if sunlight is in excess, it can lead to leaves being dehydrated and damaged. And in order to prevent such damage, plants dissipate extra light as heat.
- Previous research has shown how plants quickly adapt to changes in sunlight intensity.
- Even in very sunny conditions, only 30 per cent available sunlight is converted into sugar, and the rest is released as heat.
- The excess energy, if not released, leads to the creation of free radicals that can damage proteins and other important cellular molecules.
- So far, it has been difficult to observe the heat dissipation phenomenon, given that it occurs on a very fast time scale, in femtoseconds or quadrillionth of a second.
- Also, the energy transfer takes place over a broad range of energy levels.
Findings of the research
- Research found that excess energy is transferred from the pigment chlorophyll, which gives leaves their green colour, to other pigments called carotenoids.
- The carotenoids then release the energy as heat.
- Carotenoids are plant pigments responsible for bright red, yellow and orange hues in many fruits and vegetables.
- They also have an important antioxidant function of deactivating free radicals.
- Animals cannot manufacture carotenoids themselves; they have to get it in their diet.
- Carotenoids need to be consumed with fat in order for the body to absorb them.
- MIT researchers developed a modification to a femtosecond spectroscopic technique, which allowed them to observe over a broader range of energy levels– spanning from red light to blue light.
- Using the new technique, researchers could observe that chlorophylls absorb red light and carotenoids absorb blue and green light, thus being able to monitor energy transfer.
- Photosynthesis is a biological process that is life sustaining for all green plants.
- In this process, Light energy is converted into chemical energy, that is stored in the form of sugar molecules.
- The process takes place in the chloroplasts and it is done through chlorophyll, a photosynthetic pigment.
- It helps in synthesis of their own nutrients.
- Solar energy, water and carbon dioxide are required for this process.
- The by-product of this process is oxygen.
6CO2 + 6H2O → C6H12O6 + 6O2
Source: Wikipedia Commons
- During the process, oxygen gas is released into the environment which is essential for respiration by humans, animals and other living species .
Factors of Influence
- Light intensity
- Soil condition like pH
- Concentration of CO2
- Temperature and other climatic conditions
Stages of Photosynthesis
It takes place in two stages.
- First type of reaction takes place in day time and is called Light-dependent reactions.
- Second type of reaction is called the light-independent reaction.
- It is also called the dark reaction or the Calvin cycle.(The Calvin cycle is a process that plants and algae use to turn carbon dioxide from the air into sugar, the food autotrophs need to grow)