Biology

Kristina Gomez

BIO 100A

May 30th, 2021

Final Lab Report

Introduction

Plants are an important part of everyday life. They provide the air we breathe and are a

large source of food for both human and animal life. However, plants need food to grow just like

humans and animals. Plants need to have soil, water and the right climate in order to grow and

thrive. Plants use a process called photosynthesis in which “plants take the water from the soil,

and the carbon dioxide from the air, and they make sugars out of it” (Lawrence 2018). The plants

use the sugars as a food source. Plants also use osmosis to take in water from the soil by their

roots and transfer it to the leaves, without osmosis the plants cannot complete the process of

photosynthesis and the plant will wilt and die. If the plant does not receive sufficient water from

the soil the plant will not thrive and will eventually die. Soil has small amounts of salt but if the

salt level is too high it can have the opposite effect by absorbing the water from the soil and can

also absorb the water from the root of the plant.

Fresh water is the best solution for the overall growth of plant life. Fresh water comes

from rainfall but due to climate change, rainfall is decreasing. This has an impact on the water

used in agriculture. The water being used has a high concentrate of salt thus having an impact on

plant and crop growth. The next two experiments will help us better understand the plant

tolerance when it comes to salty soil. In the first experiment of water transport and salinity it can

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be seen how salt can enter the plant and remove the water source. While the second experiment

shows the effects of how different amounts of salt contents have on the growth of a plant.

Methods

To begin both experiments all required items needed to be gathered. The items required

for experiment one: red and blue food

coloring, salt, celery stalk, four cups,

measuring cup and a measuring spoon.

For the second experiment the required

items included: six cups, quick

sprouting radish seeds, salt, paper

towels, six zip lock bags, a measuring

cup and a measuring spoon. After all

items were gathered, the process started

with completing the second experiment

first. The six cups were labeled with the

amount of salt solution they would

contain. To start 1.5 tablespoons of salt

were added to 50 milliliters of water and

stirred well. Of this water and salt

solution 40 milliliters were poured into

the cup marked ½. Then the remainder of the cups received 40 milliliters of tap water. Next each

cup received the appropriate amount of the salter water solution until there were the different

saturated solutions listed within the instructions. At the end the cups measured: ½ at 50%

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saturated saline solution, ¼ at 25% saturated

saline solution, ⅛ at 12.5% saturated saline

solution, 1/16 at 6.3% saturated saline solution,

1/32 at 3.1% saturated saline solution and the

final cup at 0 with pure water solution. After

the water solutions were prepared a paper towel

for each cup was folded and placed into the

cup. The towels were placed onto a plate with

the correct water solution labeled above it.

Each paper towel received 15 of the quick

sprouting radish seeds. The paper towels were

then folded in half twice to saturate the seeds.

Each paper towel with the seeds were placed

into an individual ziplock bag labeled with the

solution amount. The seeds were watched over

a four day period.

The experiment #1 was completed second. All four cups received 400 milliliters of water.

Two cups received seven drops of red food

coloring while the other two cups received

seven drops of blue food coloring. Then one

cup of red water and one cup of blue water

received four tablespoons of salt and stirred

well. Two celery stalks were chosen that were

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similar in size and they were cut down the middle and placed straddled within each of the cup

sets. The celery remained within the cupps

for six hours and observed several times

within the six hour time frame.

Results

For experiment #2, the seeds were observed

every day for a four day period. The results at

the end of the four days showed that the

paper towel with pure water had the most growth with 13 out of the 15 seeds sprouting. The 1/32

saturated saline solution had the second most growth with 11 out of 15 seeds sprouting.

Only the 1/16 saturated saline solution showed additional growth with 2 seeds having just

sprouted on the fourth day. All the remaining solutions showed no signs of growth. The results

were unexpected. It was thought that all solutions would show some small type of growth.

However, the experiment showed that little to no salt is the best for plant life.

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With experiment #1, after being observed for six hours, the celery stalks were removed

from the water solutions and placed onto a paper plate. It was observed that the celery stalk that

was placed within pure water had blue coloring within the leaves at the top of the stalk. The

celery stalk that was placed in the salted water did not have any coloring on the leaves. Each

celery stalk was cut down the middle to observe the inside. On the pure water celery stalk, blue

coloring was observed from the bottom to the top of the stalk and as previously mentioned,

coloring was observed within the leaves. The red coloring was observed throughout its side of

the stock up to 19.2cm. On the salt water celery stalk was cut in a similar way to the pure water

stalk. The blue coloring was observed to reach just above the half of the stalk to the point of

where the stalk was split, which was 13.4cm high. The red coloring reached 8.6cm high. Next

the texture of the stalks were felt. The celery stalk with the pure water had more of a normal

celery texture with the bottom of the stalk having a saturated texture. The salt water stalk had a

slime texture to it at the bottom and going towards the top the stalk had started to dry. This

experiment showed just the effects of how adding salt to a grown plant can affect it by beginning

to dry out the plant from the inside. Whereas, adding pure water will assist with plant growth.

Discussion & Conclusion

Throughout both experiments it was observed how the addition of salt to plant life can

stunt growth and have the negative effect of drying out the plant from the inside. The results

show that in order for plants to thrive they must go through the process of osmosis to take in the

required amount of water needed to live. When salt levels in the soil are too high it can result in

water being withdrawn from the plant back into the soil causing the plant to dry, wilt and die. In

experiment #2 it can be seen that the high salt levels did not allow the seeds to sprout while the

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solutions with the least amount of salt were able to grow but at a slower rate compared to pure

water.

During these experiments it was expected that while the highest levels of salt solution

may not have much growth, it actually showed that salt has a big impact on plant growth. It was

surprising to witness that out of six separate solutions only two showed promise of growing plant

life and one of the remaining four solutions could show growth at a much slower rate. While

three solutions could not promote plant growth at all.

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Works Cited

Science, C. (2014, November 24). Breakthrough: How salt stops plant growth. Carnegie

Institution for Science.

https://carnegiescience.edu/news/breakthrough-how-salt-stops-plant-growth

Gibson, J. M. R. (2021, May 18). Minimize Deicer Damage with Salt Tolerant Plants.

Penn State Extension.

https://extension.psu.edu/minimize-deicer-damage-with-salt-tolerant-plants#:%7E

:text=Salts%20absorb%20and%20bind%20tightly,calcium%2C%20magnesium%

2C%20and%20potassium.

Robert Lawrence, Press & Sun-Bulletin. (2018, April 20). Ask a Scientist: How do plants

grow? Pressconnects.Com.

https://eu.pressconnects.com/story/news/local/2018/04/20/ask-scientist-how-do-pl

ants-grow/536930002/

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