Fast Plants (Marschal A. Fazio)

Research Question and HypothesisSalt tends to accumulate in irrigated soils due to the loss of water through evaporation. It is estimated that salinity in the soil affects more than 200 million acres of agricultural land, including agricultural land in California. In order to keep the salt accumulation to a minimum, water must be applied to flush the salt away from the roots. With limited supplies of fresh water for agriculture it is important to understand how salt affects the growth of plants. Scientists have only recently ( Carnegie 2013) started to understand the relationship between salt and plant growth (physiology).

My research question is, at what concentrations does salt begin to affect the growth of plants.

My hypothesis is that the salt solution even in very small amounts (1%) will inhibit the germination and growth of the Fast plants (Brassica rapa) seeds.

Standards

Investigation and Experimentation

1.Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other four strands, students should develop their own questions and perform investigations. Students will:

a. Select and use appropriate tools and technology (such as computer-linked probes, spreadsheets, and graphing calculators) to perform tests, collect data, analyze relationships, and display data.

b. Identify and communicate sources of unavoidable experimental error.

c.Identify possible reasons for inconsistent results, such as sources of error or uncontrolled conditions.

d. Formulate explanations by using logic and evidence.

e.Solve scientific problems by using quadratic equations and simple trigonometric, exponential, and logarithmic functions.

f. Distinguish between hypothesis and theory as scientific terms.

i.Analyze the locations, sequences, or time intervals that are characteristic of natural phenomena (e.g., relative ages of rocks, locations of planets over time, and succession of species in an ecosystem).

j. Recognize the issues of statistical variability and the need for controlled tests.

k. Recognize the cumulative nature of scientific evidence.

l.Analyze situations and solve problems that require combining and applying concepts from more than one area of science.

m. Investigate a science-based societal issue by researching the literature, analyzing data, and communicating the findings. Examples of issues include irradiation of food, cloning of animals by somatic cell nuclear transfer, choice of energy sources, and land and water use decisions in California.

Experimental Design

I will grow fast plants in four different conditions. Distilled Water, 1% NaCl, 2% NaCl, and 3% NaCl solutions. I will be measuring the growth of the plants every day for several weeks (until plants finish life cycle). I will be recording observations, like flowering time, number of seed, in addition to the daily measurements of plant height.

Independent variable

The Independent variable in this experiment is the time it takes for the seeds to germinate and grow. Time will be measured in hours and days.

Dependent variables

The growth of plants will be measured as time and length of the root in germinating seeds. The stem length will also be measured in the germinated seedlings. Once transplanted in the soil the stem length from soil to apical leaf node will be measured. Also time of first flowers will be noted as will number of seeds, etc.

Series

Study the height of plants (dependent variable) as a function of time (independent variable) as grown in different percent salt solutions (series). Salt solutions will be measured as percent by mass.

Constants and Controls

The amount of light and the temperature will be held constant, as will the type of soil used. Water will be given on a continuous basis using a automatic watering system. Once the plants are transplanted they will be given the same amount of fertilizer (needed to aid fast plants rapid growth). The control will be the plants grown in distilled water.

Materials

Petri dish
Whatman filters
Several 2 liter bottles with caps
Large diameter oil lamp wick
Soil (mixture of vermiculite and peat)
Fast plant seeds
Fast plant slow release fertilizer pellets
Sodium Chloride (NaCl)
Distilled Water
Fluorescent light bar

Procedures

Petri Dish Growth

From a paper towel or a piece of filter paper, cut a circle 8.5 cm in diameter to fit in the cover (larger half) of a Petri dish. With a pencil, label the bottom of the paper circle with your name, the date and the time.
Place a Transparency-plastic Ruler Disk in the cover of the germination Petri dish; place the paper circle on top. (The ruler will show through the paper circle once it is wet.)
Moisten the paper circle in the Petri dish with an eyedropper.
Place five Wisconsin Fast Plants seeds on the paper circle along the middle dark line on the ruler and cover with the bottom (smaller half) of the Petri dish.
Place the Petri dish at a steep angle (80 ̊– 90 ̊) in shallow water in a tray so that the bottom two centimeters of the paper is below the water’s surface. Each petri dish should have your 0%, 1% and 3% solutions of salt in them.
Set the experiment in a warm location (optimum temperature: 65–80 ̊F). Check the water level each day to be sure the paper circle stays wet.
On your individual data sheet record the day, time, and initial environmental conditions for the experiment.
Over the next 3 – 4 days observe the germinating seed and seedlings using a magnifying lens. (See www.fastplants.org for instructions on making an inexpensive film can hand lens.)
Measure and record the growth of the roots and shoots. Sketch the germinating seeds
and young plants using a hand lens/magnifying glass. Record all data in a data chart.

Growth Pods

Follow instructions below for building growing pods. Fill each pod with 0%, 1%, 2%, and 3% salt solutions respectively.

Sample data and graphs

Fast Plants ‎(SED 695B)‎

Analysis & Conclusions

What I found very interesting was that even very small amounts of salt (1%) slowed the germination of the fast plant seeds. In the 3% salt solution I had almost no germination at all. When the plants wer grown in the BGS (bottle growth system) I observed that the 1% solution and control had very similar growth. However the control started to have mold and algae form after a couple of days, which is usually controlled with a week solution of copper sulfate. I did not add any copper sulfate since my experiment was specifically looking at salt concentrations. The 1% showed little mold and algae growth, which means the salt may have acted as an inhibitor of the microorganism growth. The 2% solution showed very little growth and the 3% solution showed almost not growth. My hypothesis was somewhat correct, it seems many plants have very a difficult time growing in environments with large quantities of salts. I think it would be interesting to breed the few plans that did growth in the higher salt solutions and see if we can develop a strain of more salt tolerant organisms. If the salt breeding experiments were successful it could lead to engineering of agricultural crops to be more salt tolerant.

Photos & Movies

References

Fast Plants website- Official Wisconsin Fast Plant Website
Growth and Development- Guide to growing, templates and data tables included
Generalized artificial selection- Guide to generalized selection and breeding experiments (One page)
Carnegie Science- A new research as to how salt inhibits plant growth
Arizona Science- Background information on salt accumulation and soil (agriculture)
Canon CHDK- Hack for canon powershot cameras to add time-lapse scripts and motion capture abilities
ImageJ- ImageJ used for analysis of images and labeling of plant photographs.

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