Dan Tomlin APES p4 Salinity and Seed Germination

Purpose: Identify a relationship between the salinity of water used to grow seeds and its effect on the seeds’ germination and growth
Hypothesis: The seeds that are placed in less salinated water will experience more growth because salt stunts the growth of the seeds.

Procedure: Supplies:5 petri dishes, 5 test tubes, 5 petri dish sized paper towels, 20 mungbean seeds, Calcium chlorate, and a graduated cylinder.
1. Label the 5 petri dishes and test tubes with 5 different concentrations: 0% (control), 0.25%, 0.50%, 0.75%, and 1.00%
2. Measure 15 mL of distilled water using a graduated cylinder and add to the petri dish labeled 0%.
3. Add 15 mL of distilled water to test tube labeled 0.25%.
4. Mix .0375g of calcium chlorate to this test tube and stir until dissolved
5. Add 10 mL of this solution to the petri dish labeled 0.25%
6. Repeat steps 3-5 for the test tube and petri dish labeled .50% using .075g of calcium chlorate.
7. Repeat steps 3-5 for the test tube and petri dish labeled .75% using .1125g of calcium chlorate.
8. Repeat steps 3-5 for the test tube and petri dish labeled 1.00% using .15g of calcium chlorate.
9. Place 4 mungbean seeds into each petri dish
10. Place a paper towel over the mungbeans and water to keep the seeds moist.
11. Place lid over petri dishes
12. Record the length (mm) and observations of germination once a day over a 7 day period and keep the petri dishes moist.

Day
0%
0.25%
0.50%
0.75%
1.00%
1

2
11.5mm
11.5mm
10.5mm
9mm
8mm
3
11.5mm
11.5mm
11mm
9mm
8mm
4

5

6
41mm
15mm
15mm
9mm
8mm
7
45mm
18mm
16mm
9mm
8mm
8

9
80mm
20mm
30mm
10mm
12mm

Concentration
# germinated
0%
4
0.25%
4
0.50%
4
0.75%
2
1%
1

Post-Lab Analysis

1. There is a relationship between concentration of salt and the amount germinated. The more salt in the water, the less germinated
2. The more salt in the water, the less the seeds grew.
3. The procedures were rushed, so the measurements were not as precise as they should have been, so more time would have corrected many of the issues, but the main point of the lab was made.
4. Increasing levels of salt concentrations affect the seed growth because it dehydrates them like salt does to humans, preventing them from absorbing nutrients and water from the soil. Irrigation is the main cause of this because it keeps the soil waterlogged, bringing salts up to the surface, preventing the seeds at the surface of germinating and growing properly.
5. Not all seeds would be affected like the mungbeans because some seeds have developed tolerances to salt because of where they grow naturally, while others have absolutely no tolerance for salt because they did not need to adapt or evolve to become tolerant.
6. There are many methods to desalinizing soil, most only temporary. Deep tilling can improve drainage and loosen up the soil, while flushing the soil and preventing evaporation also drains the salts down below the root levels. A combination method is best because it is more long term while being cost effective.

Case Study

Desertification and salinization are two extremely prevalent and dramatic issues that plague the earth mostly due to human activity. Desertification is an increasingly common process of a relatively dry region becoming barren due to climate change and human activity. Many different factors can affect the rate and the intensity of the desertification of an area just as much as salinization. Salinization occurs when an increasing amount of salt dissolves from the soil onto the surface, causing issues with plant growth in the region. Both are very serious issues and are caused by the overuse of a region’s resources and contaminating the soil with an excess amount of chemical fertilizers and waterlogging.
In Latin America, desertification has become such a widespread issue that several nations across the globe are contributing to the preservation of the land. The primary cause of desertification in Latin America is the exploitation of the region’s resources. In many areas, the water cycle is disrupted due to excessive mining in the Andes Mountains. Large cities also require water to survive and pollute the areas around them, causing mass migrations and deaths of thousands of fish and birds. The Amazon is also home to millions of different species of plants and animals that require water, but are destroyed by logging projects, leading to the eventual desertification of the area affected. There are dozens of contributors to desertification across Latin America, but it is also a global issue.
Between 6 and 12 million square kilometers are affected by desertification, making this a very prevalent issue. On nearly every continent, there are regions at high risk for desertification. Specifically in Latin America, desertification has been and will continue to deprive them of essential water, crops, and livestock due to severe droughts that plague the regions constantly. The human activities of mining and logging disrupt the ecosystems and throw off the cycles to the point where the only solution that the ecosystem can go to is to become a desert. These issues have been addressed and are being solved by nations around the world.
Desertification is a serious issue, but can be prevented by simply not polluting or excessively exploiting a region’s resources until they literally run dry. Human activity is the main issue at hand when discussing desertification and in order to prevent it, legislation must be passed to limit the human activity in regions that are most at risk. Brazil is already working on this by disallowing the deforestation of the Amazon rainforest. However, reversing the effects of desertification is much more difficult. Seeds can be replanted and species reintroduced, but the process of recovery can take decades or even centuries. The use of tree fences is common to prevent the wind from lifting up and blowing topsoil around, preventing the growth of plants. Desertification is a serious issue and must be acknowledged so that action can be taken by more nations to prevent it in high risk regions.