Chemicals And Lack Of Soil Effect Growth, Development, And The Amount Of Nutrients Found In Brassica

For this experiment, Wisconsin Fast Plants (Brassica rapa) were grown using different techniques of modern agriculture. Three treatments were used. In Treatment A, the plants were given Miracle Gro® when planted. In Treatment B, the plants were exposed to diluted amounts of Meijer™ Brand Malathion Insect Control Concentrate twice a week and in Treatment C, the plants were grown hydroponically (without soil). After the fast plants had matured, tests were performed to determine if there was a difference in carbohydrate types, protein concentration, pigmentation, and absorption spectra. To determine carbohydrate types, a Benedict's test was performed to test for reducing sugars. A Barfoed's test was used to test for the presence of monosaccharides. A Selivanoff's test was used to determine whether aldoses or ketoses were present. A Bial's test was used to test for furanose rings. An iodine test for starch was performed for all plants as well. Pigment analysis was conducted using paper chromatography. Analysis of absorption and action spectra was also performed. In addition, light spectroscopy was used to quantify the Benedict's and Barfoed's tests so the treatments could be compared to the control group to determine if a difference in the amount of sugar production occurred. Also, plant height was recorded twice a week and the treatments were compared individually to the control using t-tests. It was found that there was a significant increase in plant size and sugar production when plants were treated with Miracle Gro® and a small decrease when plants were treated with organophosphate pesticide or grown hydroponically. No difference was found in the types of sugars present.

Agriculture has made great advances in recent years and is now a modern science. The use of chemicals and other methods for growing plants are becoming more popular as technology advances. Such methods include the use of fertilizers, hydroponics, and pesticides. As these treatments progress it is important to understand how newly available treatments on plants can effect their nutritional value. An example of this would be when an increased amount of ammonia solution is used as a fertilizer; a decreased amount of carbohydrates is produced (Hatcher, 1998).

Brassica rapa, also known as the Wisconsin Fast Plant, is a great model for researching these new technological advances. Most popularly studied at the University of Wisconsin, fast plants are ideal because of their rapid growth and fast life cycle. Dr. Williams, a researcher at the University of Wisconsin, bred these plants over a period of twenty years and brought their life cycle down from six months to a mere five weeks. Brassica rapa is also used because of their ability to survive in small environments and is also easily maintained. Today, fast plants are being used everywhere from kindergarten all the way up to college level (Anonymous-2, 2005).

In order to see if these new advancements have any effect on plant growth and nutrition, four groups of fast plants will be compared. Three of these treatments will be compared to a control group which will consist of Brassica rapa and natural soil with no additives. The other groups will include Brassica rapa grown in fertilized soil using Miracle Gro®, a group grown with an organophosphate based pesticide, and a soil absent environment also known as a hydroponic set-up. After plants have grown they will be compared using a variety of different tests. These tests include a carbohydrate, photosynthesis, and a protein analysis tests which will be used on all three treatments and the control group.

The control of the experiment is a plant grown in ordinary potting soil. The main hypothesis is that different growing techniques will yield plants with different nutritional value. Three predictions were also made for the different treatments. One of them states that there are more nutrients in plants treated with Miracle Gro® than the control due to the fact that Miracle Gro® puts more nitrogen into the soil, and areas with high nitrogen to phosphorus ratios produce more chlorophyll and have more photosynthetic activity (Carpenter, 1999). On the other hand, it was predicted that the plant treated with pesticides yields a slightly lower amount of nutrients in comparison to the control (Waliszewski, 2004). Lastly, the hydroponically-grown plant was predicted to have fewer nutrients than the control due to the difficulty inherent in growing plants hydroponically (Jensen, 2005).

Sixteen Brassica rapa seeds are to be acquired from the Carolina Biological Supply Company. Four plants will used in each treatment and the control group. For the control group, the seeds will be planted in normal potting soil in small planters. Care will be taken to make sure that the control group will not be exposed to any of the chemicals or additives being used in the other treatments. This will be done by isolating the Miracle Gro® treatment and the pesticide treatment when adding the chemicals.

Another group of plants will be designated as "Group A" and will have store-bought chemical pellet fertilizer (Miracle Gro®) mixed in with the potting soil at planting. The second group, "Group B", will be exposed to a garden variety pesticide (Meijer™ Brand Malathion Insect Control Concentrate) twice a week during watering. The final group, "Group C", will be grown in a hydroponic system.

The hydroponic system will be set up in the following way (Procedure taken from Anonymous-2, 2005). A two-liter bottle will be cut into two pieces 13 cm from the bottom of the bottle. Then the top half of the bottle will be inverted and placed inside the bottom half in order to act as a growth funnel that holds the planting medium and seeds. In the bottle cap, a hole that is Ð... cm in diameter will be punched out and be screwed onto the top half that is inverted. To serve as a wick that provides the nutrients to the plants, a 10 cm long string will be put through the hole. Next, 200 cm3 of vermiculite will be layered in the funnel and 200 cm3 of peatlite on top of the vermiculite. All of the medium inside the funnel will be soaked gently until the wick begins to drip. The Brassica rapa seeds will be soaked by placing them on a damp paper towel in a plastic bag inside the refrigerator for 48 hours. Once the seeds are fully soaked, the seeds will be gently pressed in the medium. A 1 cm layer of vermiculite will be placed over the seeds once they're planted. The medium will be moistened after that until the wick drips. Any excess water