Jerome Moore and Adam Hines Biomimetic Engineering Analysis of Heliotropic Plants 36 Biomimetic Engineering Analysis of Heliotropic Plants Jerome Moore and Adam Hines, Raytheon Corporation and Texas Tech University, Lubbock Texas, 79409, Email: [email protected] and [email protected] Received 27 June 2017; Revised 3 July 2017; Accepted 5 July 2017 Copyright c 2017 Jerome Moore and Adam Hines. This is an open access article distributed under the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Available online 7 July, 2017 at www.atlas-journal.org, doi: 10.22545/2017/00085 iomimetics is the field of study that identifies 1 Introduction potential useful biological processes and Bmechanisms in nature and translates these In a time when energy costs continue to increase principles into the engineering domain. Utilizing and concerns associated with an over dependence on natures abilities has proven to be a powerful and fossil fuels, it is advantageous for engineers and com- useful mechanism for innovation, and has led to panies to capitalize on the technological advances profound technical advancements and capabilities and capabilities that allow us to replicate nature's in applied science disciplines and fields. The main approach in harvesting energy. Biomimicry is leading objective of this paper is to introduce a Biomimicry the approach to innovation by seeking sustainable analysis of the plants ability to maintain optimal solutions to human challenges by emulating nature's sunlight in order to maximize the photosynthesis time-tested patterns and strategies [1]. Biomimetic process. The main components and factors that engineering is an interdisciplinary approach that enable heliotropism are discussed as well as the identifies potential useful processes and mechanisms governing physics describing the processes needed in biological systems and imitates them in engineer- in order for this phenomenon to occur in nature. ing systems [2]. This engineering approach is initi- The reader should emerge from this paper with an ated by identifying and analyzing a solution offered understanding of how plants are induced by sunlight by nature that may translate to an engineering prob- as well as the long-term possibility of replicating this lem. The underlying principles are understood and phenomenon for human purposes. transferred to the artificial realm through design, simulation, and fabrication. If possible, affordances Keywords: Biomimetics, Biomimicry, He- and improvements are made within the confines of liotropism, solar tracking, transdisciplinary research. the technological state [3]. Using the Biomimetic En- gineering approach, a common phenomenon that oc- curs with plants obtaining the most optimal amount of sunlight will be examined, and this process will Transdisciplinary Journal of Engineering & Science Vol. 8, pp. 36-53, 2017 ISSN: 1949-0569 online Jerome Moore and Adam Hines Biomimetic Engineering Analysis of Heliotropic Plants 37 be considered to provide viable solutions that may The all-encompassing question is, \Can the plant's produce cost-effective renewable energy for human heliotropism principles be translated by Biomimetic purposes. engineering to innovate or improve upon available First, a common ground must be established for technologies/strategies employed to harvest renew- photosynthesis and the effect heliotropism has in able energy?" The main objective of this paper enhancing its efficiency. This must be discussed to is to address the questions above by introducing a show its importance to everyday life and its ability Biomimetic Engineering analysis of the plants' abil- to maximize a process that ensures our ability to live ity to maintain optimal sunlight in order to maximize on earth. In grade school, the science curriculum the photosynthesis process. The main components commonly teaches that photosynthesis is responsible and factors that enable heliotropism are discussed for supplying all of the earth's organic compounds as well as the governing physics describing the pro- as well as the energy required to sustain life on the cesses needed in order for this phenomenon to occur planet. This process is a complex biological process in nature. The reader should emerge from this paper that harvests light energy from the sun and converts with an understanding of how plants are induced it into biological energy [4]. The energy and carbon by sunlight as well as the long-term possibility of is transmitted throughout the ecosystem as the pho- replicating the principles of this phenomenon for tosynthetic organisms are consumed or decomposed human purposes. by other organisms in a continuous, revolving circle of life. The principle inputs on the rate of photo- 2 Observation: The Plant’s Ability synthesis are available water, light wavelength and intensity [5]. However, the main factor that often to Maintain Optimal Sunlight gets overlooked is how plants ensure they obtain enough sunlight. Sunlight makes up 2 of the 3 im- Science has ingrained the principle that plants re- portant factors in the photosynthesis process. The quire the sun to grow. However, not all plants require process responsible for obtaining the precise amount the same amount of sun in order to reproduce or of ideal sunlight for photosynthesis to occur is called grow. Certain types of plants have heliotropic char- heliotropism. acteristics to ensure they can initiate photosynthesis due to climatic factors. The most common types As stated previously, heliotropism enables plants of heliotropic plants come from the legumes fam- to maintain an efficient level of sunlight in order to ily; whereas the most known heliotropic flowers are initiate the photosynthesis process. However, just Sunflowers as seen in Figure 1, Poppies, Marigolds, knowing this definition at the surface level does Daisies, and the Snow Buttercup [4]. Other com- nothing to properly quantify the enormity of this ca- monly known plants that show heliotropic abilities pability's impact on the world. Therefore, a number are alfalfa and cotton [5]. Although, a distinction of components and questions need to be addressed in needs to be made between heliotropic plants and order to fully comprehend this complex everyday pro- phototrophic plants which are closely related terms. cess. First, heliotropism is defined as the directional Phototropism is a higher level function in which or- motion of plant parts in response to the direction of ganism respond to a light stimulus. For example, the sun [6]. There are several questions that auto- when a potted plant is placed on a window sill, the matically arise when you contemplate the dynamics plant will be stimulated to lean towards the window of a flower tracking and moving in response to the in order to obtain more sunlight and increase its sun. The major questions would be the following: growth capabilities. Heliotropic plants follow the direction of the sun throughout the day. Plants • How do plants detect the sunlight? exhibiting heliotropic capabilities are not only stim- • What mechanisms enable the plant to track the ulated by the sun, but physically track the sun's sun? motion across the sky from east to west [6]. The first question tends to focus on how heliotropic • What plant features enhance its heliotropism plants can move without muscles. The easiest answer capabilities? is that they have genes that work to an \internal" • What are the fundamental physics involved in clock that corresponds with the sun's movement. the process? Scientists at the University of California Davis, de- Transdisciplinary Journal of Engineering & Science Vol. 8, pp. 36-53, 2017 ISSN: 1949-0569 online Jerome Moore and Adam Hines Biomimetic Engineering Analysis of Heliotropic Plants 38 Figure 1: The most commonly known heliotropic plant, the sunflower. termined that genes stimulate growth on the west 2.1 The Heating Hypothesis side of the stems during the evening hours when the This theory focuses on a mutualism relationship in sun is down in preparation of dawn. As a result, the which both pollinators and plants benefit by the heads/leaves of the plant orient east. When the sun heating of the sun. The heat energy absorbed by rises, growth is directed to the eastern portion of the the plant enhances seed production. Generally, pol- stems at a rate that correlates with the movement linators do not have the ability to generate their of the sun throughout the day. This growth rate is own heat and rely on the sun's heat to warm them. calibrated to a precision that enables the plants to Therefore, heliotropic plants are attractive to these \track" the sun to obtain the most amount of sunlight pollinators because they tend to be the warmest [7]. After the sun has set again, some heliotropic plants in any given habitat because of their opti- plants assume a random orientation; whereas others mal alignment with the sun at all day time hours. enable chemical reactions to return the leaf or flower This warming effect provides the pollinators with a back to the east facing orientation in preparation for comfortable environment in which they can warm dawn. The movement and gene stimulation can be themselves and/or feed off the nectar. Pollination attributed to the pulvinus or flexible sections of the then occurs which leads to the production of seeds plant that change the pressure of localized tissues [9]. The pollinator attraction hypothesis is a direct by producing increased levels of potassium ions [8]. reward for pollinators and the heliotropic plants [10]. There have been numerous hypothesis as to why these plants have this capability ranging from offen- sive tactics to attract pollinators all the way to a 2.2 The Growth Hypothesis polar opposite theory that attributes this mechanism The growth hypothesis assumes that effective ab- as a sort of a self-defense mechanism to ensure its sorption of solar energy and the resulting rise in survival.