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Walp 1IntroductionBackground:Brassica rapa (B. rapa) is a form of wild mustard from the plant family Cruciferae whichalso includes mustards, radishes, and cabbages. These crops are known for their nutritionalvalue. Dr. Paul Williams was the person to work with these ‘fast plants’ and select characteristicsthat were most useful in a classroom or laboratory setting. He bred the plants for many years,always selecting for the shortest flowering time, the most rapid seed maturations, and plants withno seed dormancy required. He selected for their ability to produce seeds even at high plantingdensity, and also a small plant size. Another selection made was made to ensure their ability togrow under continuous florescent light and in a standard potting soil. The Fast Plants that weused had a life cycle of 5 weeks. This time period is 1/5 of the time of the life cycle of theoriginal plants the Fast Plants were bred from. Our section dealt with varying the concentrationof NaCl. By doing this we are performing a single variable experiment and are able to examinethe effect chemical stress has on our Fast Plants. Salinity has a negative effect on plant growthwhen too much gathers near the roots. When there is excess salt in the root zone, water uptake ishindered and thus plant growth is hindered.Hypothesis:We expect that extreme NaCl concentration, 320 mM NaCl, will not be beneficial to thegrowth of our fast plants and will result in shorter stem height. The more moderateconcentrations of NaCl, 0 mM, 40 mM, 80 mM, and 160 mM, will promote the healthiest plantswith longer stems and more leaves.
Walp 2Null Hypothesis:We expect that extreme NaCl concentration, 320 mM NaCl, will have no effect on thegrowth of our fast plants where height or leaf count is concerned. The more moderateconcentrations of NaCl, 0 mM, 40 mM, 80 mM, and 160 mM, will also have no marked effect onour plants and we will see no change in height or leave count.Materials and MethodFor this experiment we used a total of 15 fast plant seeds, 5 salsa cups, vermiculite,Peter’s solution, peat moss, and five concentrations of NaCl: , , , , and . Webegan by preparing 5 of the salsa cups for planting. We poked a small hole in the bottom of eachcup and then placed a wick inside the hole. Three pebbles were added to the bottom of the cupand on top of that the potting mix was added. We then moistened the soil with the nutrientsolution until it dripped freeing from the wick. Three seeds were added to each of the five cupsand then covered with a small amount of vermiculite. Each cup was then watered again and thenplaced back on the tray in the reservoir. Each pot was labeled with the set concentration for easy