1. The Effects of Valerian Root on the Pulse Rate of Lumbriculus variegatus By: Jacob Squicciarini and Isabella Cox Albion High School GCC Biology 100 Variables Independent: Valerian root solution Dependent: Blackworm pulse rate Materials 10 Blackworms, spring water, 4 petri dishes, microscope, specially made slide, thermometer, 2 pipettes, clock/timer, valerian root solution, recovery bowl, coverslip Method 1.Differentiate the four petri dishes by labelling them 1, 2, 3, and untested. Also label the recovery bowl and the two pipettes. One Pipette should be labeled spring water and the other, toxin or Valerian Root. Make a table in your lab notebook where container number, time in, time out, and pulse rate can be recorded. 2.The control group should be tested first. Begin by putting a small amount of spring water in each of the four petri dishes as well as the recovery bowl. There should be enough to cover the worms but not enough to drown them. 2-4 mm of water should be enough 3.Put 10 blackworms in the petri dish marked “untested” using the pipette marked “spring water”. 4.Place one worm in the first petri dish using the spring water pipette. Make sure to mark the time. 5. After three minutes place a new worm in the second petri dish. Do the same with a third worm in the third dish after another three minutes. Mark the time each worm is placed in the dish. 6.Once the first worm has been in the spring water for ten minutes place it in the pre-cut well on the slide using the spring water pipette and cover it with a cover slip. Count the pulse rate under the microscope using the 4x lens. To count the pulse, set a timer for thirty seconds and count the number of pulses that travel through the mid section of the worm. Once thirty seconds is up, multiply the pulses counted by two and record it as the pulse rate. Immediately put the worm in the recovery bowl after the data is recorded. 7.Place a new worm in petri dish 1 and continue examining and replacing worms every ten minutes until ten worms have been tested. 8.Once the ten worms have been tested dispose of the spring water in the petri dishes and move the worms in the recovery bowl back to the “untested” petri dish. 9.Prepare the Valerian Root solution by dissolving 500mg of Valerian Root powder in 100mL of spring water. Separate the solution into three petri dishes. The same amount should go in each dish (again 2-4 mm is sufficient) 10.The blackworms should now be tested in the Valerian Root solution the same way the control was tested. However, whenever the solution is being sucked up the toxin pipette should be used and whenever spring water is being sucked up the spring water pipette should be used. Results The data shows that the valerian root solution decreased the pulse rates of the blackworms. The graph above shows the average pulse rates for both the control (spring water) and toxin (valerian root solution) tested blackworms. The average pulse rate of the control was 19 pulses per minute and that of the toxin tested group was only 15 pulses per minute. The behavior of the worms changed dramatically during the toxin testing. Most worms had little to no response to being touched on either end and were very docile in the petri dishes and under the microscope. The only exception was the worms with the large dark spots. Those worms moved a lot under the microscope and even split while being observed. Resources Drewes, CD. 2003. A toxicology primer for student inquiry: Biological Smoke Detectors. The Kansas School Naturalist, Emporia State University, 50(1);3-14 National Toxicology Program. 2009. Chemical Information Review Document for Valerian. Retrieved from http://ntp.niehs.nih.gov/ntp/noms/support_docs/valerian_nov2009_508.pdf Conclusion The data collected supports the hypothesis. The pulse rate is lower in the Valerian Root solution compared to the spring water. One thing that may have interfered with the quality of the data was testing over three days. This could have caused the worms tested towards the end of the experiment to be more stressed. The stress of the toxin as well as the extra stress from prolonged testing may have accounted for the large dark spots in the worms which made it harder to find the pulse. There was a strong correlation between these dark spots and the spike in pulse rate halfway through the toxin testing. This spike is not seen it the data because only three worms exhibited the dark spots and increased pulse rate so the average was not affected too much. Further testing could not only try to explain these dark spots but go on to retest the affects of the valerian root solution on the pulse rate or test the behavior of worms exposed to this solution. Average Pulse Rate (Pulses/minute) Introduction Lumbriculus variegatus, also known as the california blackworm, can be found throughout North America and Europe, living in shallow water where it is easy for them to feed on decaying vegetation and microorganisms. In this lab, blackworms were put through a series of tests to see how a valerian root solution would affect their pulse rate. It was hypothesized that if a blackworm is exposed to valerian root solution, then its pulse rate will decrease. Valerian root is used to treat a wide variety of common ailments such as insomnia, mood disorders, and psychological stress disorders. This over the counter drug is a sedative which means it is a central nervous system depressant. Sedatives work by blocking neurotransmitters which are responsible for communication between brain cells. Lumbriculus variegatus makes such a good test subject for this lab because its thin, transparent skin makes it easy to see the pulse traveling through the worm under a low power microscope.