Light Quality Composition As A Driver Of Plant Growth And Productivity.docx

“Light quality to enhance plant productivity” It takes eight minutes for photons that are emitted from The Sun to reach the surface of The Earth. The chloroplasts of plants contain chlorophyll, a highly conjugated pigment that absorbs said photons and convert them into energy through an electron transfer process. The light absorption spectrum of chlorophyll shows that the substance is able to perform better absorption around 450 nm (blue light) and 620 nm (red light). The research of Dr. Ronald Pierik seeks to answer the question: are we able to manipulate light conditions in order to enhance plant productivity? What are the effects of changing such light conditions in plants? To answer the questions, it is important to mention that plants own three different photon receptors in their structure: Cryptochromes, which absorb blue light and are not specific of plants, phytochromes which reversibly absorb red light and phototropin that absorbs blue light and regulates the direction in which the plant will grow, even against gravity. Blue and red light are available in a 1:1 proportion from The Sun but when plants are shading over themselves (neighbour plants), they do not absorb far-red light as efficiently, so they change their architecture to receive more of the light (they elongate and grow vertical) in a process called “shade avoidance”. One example of a plant that performs this shade avoidance is the cucumber plant, but Petunia xhybrida, Nicotiana tabacum, Tumex palustris, Arabidopsis thaliana and other plants perform it as well. Overall shade avoidance is accompanied by lower yield because the plant invests more energy in avoiding shading than in being more resistant to plagues or root development (e.g. in radish plant). Auxins are phytohormones that control plant growth, including the direction in which the plant grow thus being involved in the shade avoidance process. If we are able to take advantage of this light response in plants, growing them in better light quality conditions should improve productivity in crops of interest. “The bright box” by The Phillips Company is one example of increasing crop productivity by manipulating light quality conditions in a concept known as vertical farming. In conclusion, understanding how plants control their growth makes possible to optimize light climates, modulate specific elements of the plant development and uncouple responses from each other in a way that allows us to improve crop yield. In society this proposal not only helps increasing the yield of crops required to feed the population but also is a more efficient and thus economically good option to adopt in present and future farming. References van Gelderen, K., Kang, C., & Pierik, R. (2017). Light Signaling, Root Development, and Plasticity. Plant Physiology, 176(2), 1049-1060. doi: 10.1104/pp.17.01079