The document summarizes an experiment testing whether halotolerant bacteria can help plants grow in saltwater. It was hypothesized that basil and peppermint plants exposed to Kocuria rhizophila bacteria in saline solution would grow more than those without bacteria. In the experiment, plants were grown hydroponically in fresh water, saltwater with bacteria, or saltwater alone. Results found the plants with bacteria grew similarly to the control, while those in saltwater alone died or grew poorly, supporting the hypothesis that the bacteria help protect plants from high salinity. Statistical analysis confirmed the basil with bacteria grew as well as the control but basil without bacteria did not. Future studies could test the bacteria's effects on other crops and safety for

1. Background Research
Water possessing a higher salinity content proves ruinous to crops
during flooding, and saltwater is unable to be used as a farming asset due
to a plant’s inability to grow in that environment. Due to this occurrence,
there must be a solution to allow for plants to continue to thrive even when
faced with a flood of saltwater.
While performing the experiment in a hydroponic setup, bacteria in the
saltwater is hypothesized to react similarly and result in growth despite the
presence of salt in the water. In this experiment, the addition of the
halotolerant Kocuria rhizophila will allow the rhizomes of the plants to
absorb the bacteria which will then help them survive in the saltwater
solution. It is expected that once the plants absorb the bacteria, they too
will be able to survive in the saltwater solution that will be used in this
setup. Bacteria converts plant waste into nitrogen in a symbiotic
relationship, the addition of the bacteria helps the plant thrive by creating a
biofilm over the rhizome to increase survivability in saltwater, so the salt
tolerant qualities of the plants allow the plants to grow in this
environment.
The plants being used in this experiment are sweet basil, Ocimum
bacilicum, and peppermint, Mentha piperita. Peppermint plants can be
mildly exposed to saltwater in very low doses, but it cannot be fully
exposed to high concentrations of saltwater. Sweet basil is moderately
tolerant to saltwater if the seeds are exposed to a low concentration.
Because this experiment requires a full immersion of the roots of the
plants into salt water, the K. rhizophila is crucial in order to achieve the
desired results. Because the saltxwater is hypertonic as compared to the
plant, the water in the plants roots gets drawn out due to the higher
concentration of salt. It is hoped that the bacteria will counteract the
salinity of the water to result in a good balance for the plants to grow well
in. If proven successful there would be a positive impact in the farming
and gardening community.
Tolerance of Mentha piperita and Ocimum basilicum to a high salinity environment in a
hydroponic system with the addition of halotolerant Kocuria rhizophila bacteria
Hypothesis
If the plants are exposed to the Kocuria rhizophila bacteria in a saline
solution, then they will have more growth than the plants in a saline
solution that are not exposed to the bacteria, because the bacteria’s
halotolerance will protect the plants from the high salinity while the plants
without the presence of K. rhizophila will not have protection from the
saltwater.
Procedure
1. Set up four hydroponic tubs (42.2cm L, 29.8cm W, 17.8cm Hgt)
2. Plant three Mentha piperita and three Ocimum basilicum seeds in each
rockwool and place the wool into the hydroponics cups
3. Every hydroponic tub will begin with fresh water and plant nutrients
4. The aerators and growth light must stay on all day long.
5. When all plants reach full maturity ( approximately 6 weeks) begin
adding saltwater to the tanks (all water added contains nutrients)
-Tank 1: control, 8 L of freshwater
-Tank 2: 6 L saltwater, 2 L of bacteria
-Tank 3: 6 L saltwater, 2 L freshwater
1. Add 3 ml of bacteria to each rockwool in tank 2 to increase the
bacteria’s effect
2. After a week (when there is an observable difference in the plant's)
measure and record the biomass of all the plants in tank 1, 2, and 3
3. Put all plants in a dehydrator, and record mass of the dehydrated plants
4. Compare data between all 3 tanks
Future Study
In the future, it would be beneficial to test varying solutions of bacteria
on the plants. Also, crop plants, such as lettuce, corn, pumpkin, etc. would
be tested with K. rhizophila. This would be helpful to local farmers due to
more recent flooding out near farms on the eastern end of Long Island. In
addition, multiple test need to be done to ensure that crops that come in
contact with K. rhizophila would be safe to consume.
Conclusion
At the conclusion of the experiment, the hypothesis was supported by
the results. The plants thrived in the saltwater with bacteria solution in
comparison to the plants that died in the saltwater only solution. There was
also an obvious difference in the quality of the roots, as the plants in the
saltwater with no bacteria were brown and covered in a sludge-like
substance while the plants in the bacteria solution had roots similar to the
plants with the same color and texture as those in the control tank. An
ANOVA test was performed on all data and the tests provided evidence
that there was a statistical difference with the water mass in the basil
plants. A t-Test: Two Sample Assuming Unequal Variances was then
performed to determine the statistical difference. This test showed that
there was a statistical difference between the basil in freshwater and basil
in saltwater ( P-value = 0.011). Also, it showed that there was no statistical
difference between basil in freshwater and basil with a saltwater and
bacteria solution (P-value = 0.096). Therefore the basil with bacteria and
saltwater grew just as well as basil in freshwater. The basil that grew in
just saltwater did not as grow as well as the basil in freshwater. An
ANOVA test was also performed on the mint plants. However, no
statistical difference was found (P-value>0.05).
Tank 1: Control tank - freshwater only, no bacteria
Tank 2: Saltwater tank with bacteria
Tank 3: Saltwater tank - no bacteria
Dehydrated Mass versus
Total Mass of the Basil Plants
Dehydrated Mass versus
Total Mass of the Mint Plants
A C
B
D E F
Mass
(g)
Figure 1:
A: Basil root in freshwater tank D: Mint root in freshwater tank
B: Basil in saltwater with bacteria tank E: Mint in saltwater with bacteria tank
C: Basil in saltwater tank F: Mint in saltwater tank
Mass
(g)
Photos taken by Paige Bzdyk