To Grow or Not to Grow?The Effects of Nitric Acid on Plant Growth Biology 6C Field Project ReportsExperimental Date: July 13, 2015 ~ July 25, 2015Present Date: August 4, 2015Group 4 Members: Alisha Meada, Dodo Qian, Giang Ho, and Simon Siu

Background InformationSeed, Soil, Acid Rain, and Chemical ComponentsWhat is Acid Rain?Acid rain is the result of nitrogen and sulfur pollutants from factory and auto emissionsIn cooler climates acid rain can also present itself as acid snow or acid fogNitrogen dioxide (NO2) reacts with water (H2O) and oxygen (O2) in the atmosphere to form nitric acid (HNO3)4 NO2 + 2 H2O + O2 4 HNO3The pH of acid rain can range anywhere as low as 2.0 to 5.0Wide range of severityWhat is Acid Rain?

What is Acid Rain?

The SeedMung Bean / Green Gram (Vigna radiate)Mainly cultivated in Southeast AsiaGerminates within 1-3 daysGrows best in soils with a pH of 5.5 to 6.5Can be grown in both direct sunlight and shaded conditionsMung bean plants display a constant growth rate

http://pss.uvm.edu/ppp/pubs/oh34.htmThe SoilLoam soil Composed mostly of sand and silt, and a smaller amount of clay (about 40% - 40% - 20% concentration, respectively).Holds a good amount of moisture which aids in the growth of plants40% - 60% of the volume is pore space filled with air or waterLoam is commonly used in agriculture and gardening practicesGood candidate because their is limited time for the experiment.

The Effects of Acid RainLoss of nutrients: Acid rain dissolves and washes away nutrients in the soil before plants get the chance to process themStunts plant growth !Interference of photosynthesis: The acid from the rain causes damage to leaves on plantsThreatening aquatic lives: Acid rain also affects aquatic environmentsKills off aquatic organisms such as fish !http://www.epa.gov/acidrain/effects/surface_water.htmlWhy Should We Care?Anthropogenic causes are a large contributing factor to acid rain.ITS PREVENTABLE!

QuestionsHow does acid rain affect plants?Why is there poor plant growth in a polluted area, such as Los Angeles, versus San Jose?Does acid rain affect the growth or physical appearance of plants?Why some plants look shorter and yellowish than others?Hypothesis and PredictionHypothesisPlants watered with solutions of different concentrations of nitric acid will show a slower/stunted plant growth and germination.Alternative HypothesisThere is no difference of the plant growth and germination among the plants watered with solutions of different concentrations of nitric acid.PredictionIf plant samples are watered with solutions with a high concentration of nitric acid, then the germination time and the growth rate will be significantly lower than the plant samples watered with less a concentrated nitric acid solution.ExperimentLocation, Chemicals, Method, Variables, and Standardized MeasurementLocationHome - Shady areaLab Room

The Chemical SolutionsNitric Acid (HNO3)Used to mimic the different pH levels of acid rainComponent is found in acid rain4 NO2 + 2 H2O + O2 4 HNO3

Equipments:pH MeterEgg Trays50ml centrifuge tubes Pipette

Method / Procedure36 seeds were divided into 6 groups, a certain pH value per group (pH=4, 4.8, 5.5, 6.0, 6.5, 7.0). 2 egg tray holes per group, 3 seeds per hole. The seeds were covered with ~0.5cm of soil when planted.Five groups were watered with a different solution of a specific nitric acid concentration. The last group was watered with tap water from the lab room.The amount of watering solution was 1.3ml per day (all watered at night).The experiment was conducted for a few days, and the germination date was recorded.Once all the plants had germinated, an additional experiment was conducted for 6 days to purely analyze the growth rate of the plants. The plants length was measured at night.

VariablesControlled VariableIndependent VariableDependent VariableVariablesControlled VariableWatering ( 1.3 mL per hole per day)Location (indoor, shady)Same amount of soil3 seeds were placed in one holeTemperatureVariablesIndependent VariableThe concentration of nitric acidControl: Solution without nitric acid (Tap Water)VariablesDependent VariableGermination TimeStem LengthStandardized Measurement

Standardized MeasurementStandardized MethodStem Length (cm)1 Decimal PlaceData & ResultsRaw Data, Line Graphs, and Bar Charts

Table 1: Germination Time of Plants Watered with Different pH Solutions

High concentration of nitric acid >>>> Long Germination timeMild concentration of nitric acid >>>> Short Germination timeLow/Without nitric acid (Tap Water) >>>> Mild Germination timeJuly 20, 2015

pH = 4.0 pH = 4.8 pH = 5.5 pH = 6.5 pH = 6.0 pH = 7.0July 21, 2015

pH = 4.0 pH = 4.8 pH = 5.5 pH = 6.5 pH = 6.0 pH = 7.0July 22, 2015

pH = 4.0 pH = 4.8 pH = 5.5 pH = 6.5 pH = 6.0 pH = 7.0July 23, 2015

pH = 4.0 pH = 4.8 pH = 5.5 pH = 6.5 pH = 6.0 pH = 7.0July 24, 2015

pH = 4.0 pH = 4.8 pH = 5.5 pH = 6.5 pH = 6.0 pH = 7.0July 25, 2015

pH = 4.0 pH = 4.8 pH = 5.5 pH = 6.5 pH = 6.0 pH = 7.0

Table 2: Stem Length of Plants Watered with Different pH Solutions unit: cmTable 3: Mean Stem Length of Plants Watered with Different pH Solutions

unit: cm

High concentration of nitric acid >>>> Low growth rateMild/Low concentration of nitric acid >>>> Fast growth rateWithout nitric acid (Tap Water) >>>> Lowest growth rate

Correlation?Table 4: Comparison of Germination Time to Grow RateGermination Time (days)Grow Rate (cm/day)pH = 4.06.7 0.40.4429pH = 4.86.8 0.30.7043pH = 5.53.0 0.01.8310pH = 6.03.8 0.31.1081pH = 6.55.3 0.41.1833pH = 7.06.3 0.40.1714r-value = - 0.848r-critical (0.05) = 0.811 Correlation?The correlation is significant with 95 % confidenceFor our data, r-value is closer to -1The correlation coefficient (r) will fall between -1 and +1 where -1 is a perfect negative correlation, +1 is a perfect positive correlation and 0 is no correlationLonger Germination Time >>>> Lower Growth RateShorter Germination Time >>>> Higher Growth Rate

DiscussionResult Analysis and Possible ExplanationsData AnalysisHighly acidic solution (Higher concentration of nitric acid): pH=4 & 4.8 >>> Longer germination time and slower growth rateSlightly acidic solution: pH = 5.5, 6, 6.5 >>> SHORTEST Germination Time and the FASTEST Growth RateTap water (without nitric acid): pH=7 >>>longer germination time and slower growth ratePossible ExplanationsHighly Acidic SolutionNutrients in soil provide the essentials for plant to growEven though acidic solution dissolves most of the nutrients, H+ competes with other ions in soil for root absorption.Acidic environment interfere the enzymatic activities of the plants. (-amylase)Some microbes in soil are unable to tolerate and survive in a highly acidic environment.Possible ExplanationsSlightly Acidic SolutionDissolve most of the nutrients in soilEasy for plants to absorb nutrients in aqueous formAbsorb faster >>>> Germinate faster >>>> Grow fasterPossible ExplanationsTap Water (without nitric acid)Tap water is hard water, which contains contaminants (e.g. heavy metals, toxic chemicals , medication, salts)Without nitrate ions, plants grow slowerConclusionConclusionThe hypothesis is supportedExamined that there is a correlation between the nitric acid concentration and the germination and growth rate of the plantHighly acidic environment will hinder the plant germination and growConservationConsequence & ImprovementsConsequenceOutrageous usage of fertilizer >>>> causing more hazardous acid rainImproper emission of nitrogen oxides >>>> causing large area effectsWhat Can We Do to Help?Switch from artificial fertilizers to compost.Contains less nitrogen than fertilizer (~2%)Organic; ensures that whats being removed from the cycle is replacedReduce automobile emissionsCarpoolChoose public transportationReduce industrial emissionsConserve electricity

http://epa.gov/climatechange/ghgemissions/gases/n2o.htmlhttp://www.calrecycle.ca.gov/organics/compostmulch/CompostIs.htm

Improving the ExperimentCausation? and Future ExperimentCausation?Nitric acid, when dissolved in water, there are two components: hydronium ions and nitrate ionspH value depends on the hydronium ionsNitrate ions is one of major component in fertilizerCausation?Is pH of the solution affecting the growth rate?Or the concentration of the nitrate affecting the growth rate?Future ExperimentTesting the effect of pH:using acid with stable anions that do not affect the growth of the plant. (e.g. HF, H2CO3)Testing the effect of the concentration of the nitrate:using FeNO3 instead of HNO3, which does not affect the pH valueFe shouldnt affect the growth rateBibliographyTennesen, Michael. "Sour Showers: Acid Rain Returns--This Time It Is Caused by Nitrogen Emissions." Scientific American Global RSS. N.p., 21 June 2010. Web. 02 Aug. 2015.Heyer, Bruce. "Ecosystems." (n.d.): n. pag. Web. 2 Aug. 2015."The Acid Rain." CAN SULPHURIC ACID BE OUR FRIEND? N.p., n.d. Web. 02 Aug. 2015.Kidd, Petra S., and John Proctor. "Why Plants Grow Poorly on Very Acid Soils: Are Ecologists Missing the Obvious?" Journal of Experimental Botany. N.p., 10 Oct. 2000. Web. 2 Aug. 2015."Water Plants with Club Soda to Make Them Grow Faster and Healthier."Lifehacker. N.p., 24 Apr. 2014. Web. 02 Aug. 2015.Maffei, Massimo E. "Magnetic Field Effects on Plant Growth, Development, and Evolution." Frontiers in Plant Science. Frontiers Media S.A., n.d. Web. 02 Aug. 2015."Effects of Acid Rain - Forests." EPA. Environmental Protection Agency, 24 Dec. 2012. Web. 2 Aug. 2015. ."Effects of Acid Rain - Surface Waters and Aquatic Animals." EPA. Environmental Protection Agency, 4 Dec. 2012. Web. 2 Aug. 2015. ."PH for the Garden." PH for the Garden. University of Vermont Extension, 2003. Web. 2 Aug. 2015. ."Acid Rain." Chemwiki. UC Davis. Web. 2 Aug. 2015. .

AcknowledgmentsThank you Prof. Heyer!!(Provide equipments, solutions, and ADVICE!!)Q & A