Emerson Enhancement Effect: Definition, Effect

What Is the Emerson Enhancement Effect?

Suppose plants are under the influence of two different wavelengths simultaneously. In that case, they increase considerably relative to the sum of the rates when they are under the influence of each wavelength separately. This discovery was made by Robert Emerson and allows for coherent interaction between photosystem I and photosystem II in the light-dependent reactions of photosynthesis. This effect underlined the necessity of understanding how different components in a photosynthetic apparatus cooperate to maximize energy capture and conversion.

Discovery and Experiment by Robert Emerson

The Emerson Enhancement Effect was first noticed through experiments conducted by Robert Emerson in the 1950s.

Concept And Discovery

Emerson exposed algae to red light, far-red light, and a combination of both and measured the rate of photosynthesis. He found that if the algae were exposed to the two wavelengths at the same time, then the photosynthetic rate exceeded the sum of the rates under each wavelength alone. This phenomenon showed that the two photosystems of plants, Photosystem I and Photosystem II, cooperate to enhance the optimal utilization of light energy.

Mechanism of the Emerson Enhancement Effect

The mechanism of the Emerson enhancement effect is:

Light Absorption and Energy Transfer

The Emerson enhancement effect enhances the photosynthesis rate by optimizing the absorption of light energy along a wide wavelength range. Photosystem II mainly absorbs the light at a wavelength of 680 nanometers which corresponds to red light. At the same time, Photosystem I absorbs light around 700 nanometers which corresponds to far-red light.

Cooperative Function of PS I & PS II

During the process in which both photosystems are triggered together by their respective wavelengths, the net efficiency of light reactions of photosynthesis increases tremendously. These two photosystems can work together to make the transfer of electrons through the electron transport chain much more efficient, boosting the production of ATP and NADPH for the Calvin cycle. Graphs indicate that there is an increase in photosynthetic activity with the application of both lights together.

Factors Influencing the Emerson Enhancement Effect

Several factors can influence the effect of the Emerson enhancement effect:

Biological Significance of the Emerson Enhancement Effect

The biological significance of the Emerson enhancement effect is:

Confirmation of Two Photosystems

The Emerson Enhancement Effect is very essential in ensuring photosynthetic efficiency through the optimization of the interaction between Photosystem I and Photosystem II.

Enhanced Photosynthetic Efficiency

The two photosystems in plants work together and have a higher overall photosynthesis since it can capture light energy effectively and convert it into chemical energy. This cooperation increases ATP and NADPH, which is essential for Calvin cycle and carbon fixation.

Foundation for the Z-Scheme Model

It gave proof that electrons flow in the “Z-shaped” pathway between the two photosystems. This flow produces ATP and NADPH without electrons without returning to the starting point, known as non-cyclic photophosphorylation.

Agricultural Applications

The principles of the Emerson Enhancement Effect have important implications for agriculture. By understanding and applying these principles, one can optimize the agricultural process to allow crops to grow more strongly and quickly.

This is, for instance, possible through the use of artificial lighting systems mimicking optimal wavelengths for Photosystem I and Photosystem II in controlled greenhouse settings, which optimizes photosynthesis. Hence, this would result in high productivity and efficiency of crops, hence higher yields and resource utilization.

Emerson Enhancement Effect NEET MCQs (With Answers & Explanations)

Important topics for NEET are:

• Discovery and Mechanism of Emerson Effect

• Factor influencing Emerson Effect

Practice Questions for NEET

Q1. Emerson's enhancement effect and Red drop have been instrumental in the discovery of:

1. Photophosphorylation and non-cyclic electron transport

2. Two photosystems operating simultaneously

3. Photophosphorylation and cyclic electron transport

4. Oxidative phosphorylation

Correct answer: 2) Two photosystems operating simultaneously

Explanation:

The sharp reduction in the rate of photosynthesis when monochromatic light of more than 680 nm wavelength (red region) was used alone.

Emerson Enhancement Effect:

Simultaneous application of light of shorter and longer wavelengths increases the rate of photosynthesis.

Emersion Effect

Emerson's enhancement effect and red drop are due to the presence of two photosystems, PS I and PS II.

Hence, the correct answer is option 2) Two photosystems operating simultaneously.

Q2. The Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to the light of wavelength _____ and______.

1. 600 nm and 700 nm

2. 670 m and 700 m

3. 670 nm and 700 nm

4. 700 nm and 670 nm

Correct answer: 3) 670 nm and 700 nm

Explanation:

The Emerson effect is the enhancement in the rate of photosynthesis after the chloroplasts have been exposed to light of wavelengths 680 nm and 700 nm.

The effect represents the phenomenon where two unlike wavelengths of light when used jointly, improve the rate of photosynthesis better than if wavelengths were used individually. These wavelengths correspond to the absorption peaks of photosystem II (680 nm) and photosystem I (700 nm).

Hence, the correct answer is option 3) 670 nm and 700 nm.

Q3. Emerson enhancement occurs when

1. Light of shorter wavelength was given along with 680 nm.

2. Light of greater wavelength was used alone

3. Light of shorter wavelength was used alone

4. light of shorter wavelength was used along with 400nm

Correct answer: 3) Light of shorter wavelength was used alone

Explanation:

The inefficient far-red light beyond 680nm could be made fully efficient if supplemented with the light of shorter wavelength (blue light). The quantum yield from the two combined beams of light was found to be greater than the sum effects of both beams used separately. This enhancement of photosynthesis is called Emerson's Enhancement Effect.

Hence, the correct answer is option 3) Light of shorter wavelength was used alone.

Also Read:

• MCQs on Emerson Enhancement Effect

• C4 and CAM Pathway

• Difference between Photosystem 1 and Photosystem 2

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