The effect of mycorrhizae on the growth rate of Raphanus sativus (radish)Phillip C. SargentDepartment of Biological SciencesSaddleback College Mission Viejo, CA 92692AbstractMycorrhize is a type of fungus found in the phylum Zygomycota. It is generally known for forming mutaliasic relationships with plant roots where the mycorrhizal fungus provides the inorganic nutrients and in return the plant gives the mycorrhizal fungus the nutrients necessary to survive. This relationship has been shown to increase the plants inorganic nutrient intake, which allows the plant to grow bigger than plants that are not infected with the Fungus. This leads to the question of what would be the effect of a large volume of mycorrhizal fungus added to a low phosphorous/low fertilized environment on the growth rate of plants. Twenty seven Raphanus sativus seeds were planted in nine pots, three to a pot. These pots where divided into three groups. Control, which had no mycorrhizal fungus in the soil, and two others with mycorrhizal fungus; 5 mL and 10 mL. After all seeds in the pots had germinated one plant was chosen to use and the others were uprooted. These were allowed to grow for four weeks being measured once each week in number of leaves and length of leaves. After the four weeks the plants growth rate was calculated in each category. These were tested in an ANOVA test. It was found that there was no statistical difference between any of the control, 5 mL, 10mL groups in number of leaves or in leaf length. IntroductionFungi are often associated mostly with decomposers and parasites. However thereare certain species of fungi which are under the category of mycorrhize. This group is found in the Phylum Zygomycota and generally forms a mutalistic relationship with plantroot systems. This is achieved by the process of the fungus increasing the plants phosphorus intake along with other inorganic resources by extending speclized structures called Haustoria in to cells plant. In return the plant provides the nutrients needed for the fungus to survive (Marschner 2002). Mycorrhizal fungus can be beneficial as long as the net gain of the plants resources is positive. However, at times, mycorrhizal fungus also has the potential to be harmful to plants in more extreme environments (Reynolds, et. al.,2004) such as too much fertilizer (Johnson, 1993) or during periods where resources are scarce, such as drought. (Franzini et. al.,2010). An example of a beneficial reaction to mycorrhizal fungus was found in 1979 by researchers Thomas Moorman and F. Brent Reeves, who found the mycorrhizal fungus is beneficial to regeneration of overused land,such as former mines. This could also be beneficial in burned areas. For example, a study in 1988 revealed (Klopatek et. al.) that fire lowered the arbuscular mycorrhizae content inthe soils. The results will however depend on the types of mycorrhizae used as the beneficial properties vary from plant to plant. This is because it was found in 2011 that crop growth such as maize were affected by different Mycrrhizae types (Ortas, I.,& Akpinar, C. 2011). Also, in highly fertilized situations a faster growth rate is experienced (R. T. Lamar and C. B. Davey (1988)).This study was specifically focused on the micorrhizal fungus on growth rates of the plants infected with large amounts the fungus in poorer soil conditions. This research is vital because of the potential it poses to speed up crop growth in poorer soil conditions with limited amount of fertilizer necessary. This study was also commenced to try to determine if doubling the concentration of mycorrhizal fungus will double the growth rate when the fungus’s concentration is doubled. The expectation was that there would be a significantly greater difference between the growth rate of a plant with a soil with mycorrhiaze than a plant with a soil without the fungus due to the increased nutrient intake. This should be in accordance with a study by Roger T. Koide in 1991, who found similar results. They found that the mycorrhizal fungi increased plant growth. The research also predicted that there would be no significant difference between the two mycorrhizae groups growth rate in the long term.Materials and MethodsThe soil chosen was a mixture of dirt out of the Sargent’s Garden mixed in with plain dirt. This was done to ensure that the plants would contain similar low fertilized soil conditions (Johnson, 1993). The mycorrizal fungus was added and mixed into the soil prior to planting the seeds. The soil was split into three groups; two with mycorrizal fungus and one without the fungus acting as the control group. The two with mycorrhiazeare split into one group with 5ml and one with 10ml of mycorrhizal fungus. The pots were then labeled. Control was the group with no mycorrhizal fungus added. The group with 5ml mycorrhizal fungus added was labeled 1x. Finally, the 10ml group was labeled 2x. Each group was split further into three tests to differentiate between each pot. Then twenty-seven Raphanus sativus seeds were chosen from a bag of seeds purchased from Home Depo. Three seeds were placed into an individual pot. These seeds were placed be approximately 4cm apart from each other and one centimeter deep. The plants will be allowed to germinate till each pot had at least one plant, and then two plants per pot were removed leaving one plant per pot. The plants were allowed to grow for a period of four weeks, where their leaf length was measured once a week by measuring from stem to the tip of the leaf through the middle of the leaf with a standard 30cm ruler. The leaves were measured from the outermost leaves to the inner leaves last measured. Also the number ofleaves the plant had was tracked. Throughout the four weeks the water the plants receivedwas constant even though the time between watering was not. When watering, all the plants were watered at the same time. After the four-week period was over the plants were dug up and their mass was measured. This data was then used to calculate growth rate.ResultsThere were three leaf types of leaves measured throughout the growth period of four weeks. Type one was the first to sprout, and type two was soon to follow however only two grew of each of those types. The type three leaves were the last to grow but grew the most number of leaves. The average number of leaves was recorded in an table 1.Control 5 mL 10 mL24-Oct 3.3 4 4.330-Oct 4.7 4.7 65-Nov 7.0 7.0 7.011-Nov 7.0