By Timur Maryia
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Photosynthetically Active Radiation (PAR)
The spectrum of light that plants use for photosynthesis, namely in the wavelength range of 400 to 700 nanometers, is known as photosynthetically active radiation, or PAR. The energy transformation activities in plants that result in the synthesis of organic matter depend on this radiation.
The Importance of Light in Photosynthesis
As light energy starts the light-dependent reactions occurring in the thylakoid membranes of chloroplasts, light energy is a basic need for the photosynthetic process. Certain light wavelengths, mainly red and blue light, are absorbed by chlorophyll during these reactions. This energises electrons and makes it easier for solar energy to be converted into chemical energy in the form of ATP and NADPH.
Mechanisms of Light Absorption
The primary pigment in plants, chlorophyll, is essential for absorbing light energy. Plants are typically green because it reflects green light and absorbs most of the light in the red (about 660 nm) and blue (around 440 nm) sections of the spectrum. Plants are able to efficiently use the available solar energy for photosynthesis because of this selective absorption.
Impact of Light Quality on Photosynthesis
The PAR spectrum's varied wavelengths have varying effects on the rates of photosynthesis. Research has indicated that the optimal wavelengths for stimulating photosynthetic activity are blue and red light, however green light is less effective since it is reflected by chlorophyll. Comprehending these processes is crucial for enhancing plant output and optimizing growth conditions in agricultural techniques.
Environmental Factors Affecting Light Availability
In addition to meteorological conditions and sun position, other factors that affect PAR availability include nearby vegetation and canopy cover. The amount of light that reaches lower leaves can be reduced by other plants shading them, which can have an impact on the photosynthetic efficiency and general health of the plant.
References:
Lents, N. H., & Nishan, J. (2017, February 12). Photosynthesis I. Visionlearning. https://www.visionlearning.com/en/library/biology/2/photosynthesis-i/192
10 Facts on Photosynthesis. (2019, November 22). Sciencing. https://sciencing.com/10-photosynthesis-7257331.html
Lambers, H., & Bassham, J. A. (2024, August 9). Photosynthesis | Definition, Formula, Process, Diagram, Reactants, Products, & Facts. Encyclopedia Britannica. https://www.britannica.com/science/photosynthesis
Helmenstine, A. M. (2018, June 18). 10 Fascinating Photosynthesis Facts. ThoughtCo. https://www.thoughtco.com/photosynthesis-facts-4169940