A Comparative Analysis of Two Plant Growth Mediums ...

Running Head: HYDROPONICS VS. SOIL

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A Comparative Analysis of Two Plant Growth Mediums: Hydroponic vs. Soil Maeva Makendi S.G

The Academy of Science, Research and Medicine at THE Paulding County High School

Running Head: HYDROPONICS VS. SOIL

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Table of Contents

Table of Contents.............................................................................. 2

Abstract.......................................................................................... 3

Introduction..................................................................................... 4-7

Methods & Materials...........................................................................8-10

Results............................................................................................11-20

Discussions...................................................................................... 21-24

References........................................................................................25

Appendix.........................................................................................26-27

Running Head: HYDROPONICS VS. SOIL

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Abstract

Plants do not need soil in order to grow and survive. Soil act as a medium for plant to help support it and to retain nutrients. However, any medium that is stable enough to support plant and can retain nutrients can do the same job as soil without being restricted to the ground. This is where hydroponics comes in; hydroponic is a method of growing plants using mineral solution, in water, without soil. This method can be extremely helpful to countries that have poor land, which is not able to sustain agriculture. The purpose of this lab is to prove that hydroponic horticulture can be just as effective if not better than plants traditionally grown in soil. The hypothesis goes like this if the hydroponic plants and plants grown in soil are given the same germinating and growing conditions, then the hydroponic plants will do as well if not even better than the plants grown in soil. This experience was conducted using an assortment of fruit, vegetables and herbs. Half the seeds where grown hydroponically, while the other half was grown in soil; both were kept in the same conditions, in order to not alter the experiment in favor of one or the other. The plants were grown for thirty days, in order to ensure accurate results. After a month the stated hypothesis was proven correct, the hydroponic and soil plants grew almost the same, with the hydroponic plants germinating faster and growing faster than the soil plants.

Running Head: HYDROPONICS VS. SOIL

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Introduction

Often time when learning about plants, we stumble unto the basic so called necessities of plants, the big four as some call it, sun, soil, oxygen and water. Three out of the four basic necessities given are true. Plants are autotrophs that make their own food using the sun using a process called photosynthesis. The word photosynthesis means to put together with light and this is exactly what occurs. It occurs in the chloroplasts of plants. This process is limited to the supply of light, water and carbon dioxide. Limiting any one of the factors on the left can greatly impact the amount of photosynthesis produced. During the process of photosynthesis electrons are boosted up by the energy from the sunlight. The chloroplast uses these electrons, along with the carbon dioxide and hydrogen ions, to produce sugar molecules (Campbell et al., 2009). The reaction steps add up to the following photosynthetic equation:

Photosynthesis occurs in two stages, the light dependent reaction and the Calvin cycle, both with their own individual steps. In the light reaction the energy in sunlight is converted to chemical energy. The reaction relies on molecules built in the membranes of thylakoids. First, light energy is captured by the chlorophyll molecules in membranes. Then the captured energy is used by the thylakoid to remove electrons from water. This divides the water into oxygen and hydrogen ions. This are considered waste products and are used to make NADPH. The captured energy is also used to generate ATP. The Calvin cycle makes sugar from the atoms in carbon dioxide including

Running Head: HYDROPONICS VS. SOIL

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the hydrogen ions and electrons carried in NADPH. The ATP made in the light reaction provides the energy needed to make to sugar. The Calvin cycle is known as the "light independent reaction" because it does not need light to begin. However, it does need ATP and NADPH which comes from the light cycle (Williamson et al. 2009). It is obvious to see that the sun or light is an important contributor to plant growth and development.

The fact that plants need oxygen is unarguable. This is because all cells not just plant cells need oxygen to perform aerobic respiration. Respiration is the process of breaking down food to get energy. The cells in the green part of plants where photosynthesis is occurring get the oxygen they need from the oxygen produced by photosynthesis. This means that the cells in the leaves and stems of the plants are getting adequate requirements. The problem comes from the cells in the roots of the plants, where there is no photosynthesis occurring due to the lack of light. In the majority of plants this cells get their oxygen from air in the spaces between the dirt particles in the soil. "All living things combine food with oxygen to attain energy. Plants are no exception. They make food and combine it with oxygen in order to release energy for themselves. On the contrary, during day time, plants release lots of oxygen in the air because while making food during photosynthesis, they change carbon dioxide and water into food and oxygen. But, at the night time, just like other living beings, plants absorb oxygen to breath" (Insaan, n.d.). If the plants have no access to oxygen there would not be any respiration and the plant would not be able to function. Due to the lack of oxygen the roots will not be able to grow to take in water, which would cut off the nutrients needed for the plants to grow and survive.

Plants need water to grow. One of the major factors driving water movement in plants is transpiration. Transpiration is the loss of water from plants in the form of vapor (evaporation). Plants use 95% of the water absorbed from soil for transpiration, 5% is used during

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