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Increased Salinity of Water Decreases Brassica rapa Growth
Alexa Aragon and David Lee
University of Notre Dame
Materials and Methods
• Experimental Organism: Brassica rapa was selected
for its fast growth rate.
•Sea levels are predicted to rise between 0.2-0.6m in
the next 100 years (EPA 2011).
• Two groups of 16 planting cells were filled with three
seeds each. Three 14-14-14 fertilizer pellets were also
added to each cell.
•The ability of plants in these coastal areas to adapt
to the increased water salinity is largely unknown.
Salinity is a major environmental factor limiting plant
growth and productivity (Allakhverdiev et al., 2000b).
•This experiment investigated the degree to which
Brassica rapa growth is affected by increased salinity.
Plant growth was expected to be reduced by
increased sodium chloride concentrations in water.
Discussion
Compared Biomass of Experimental and Control Groups
• Rises in global temperatures are predicted to
increase sea levels due to the melting of polar ice
caps and the thermal expansion of water.
•Increased sea levels result in the intrusion of sea
water into connected wetlands and rivers (Figure 1).
Results
1.2
1
p-value=.026
t-value= -2.94
0.8
•Plants were grown under the same conditions in a
controlled greenhouse environment.
Biomass(g)
Introduction
•After five days, the three plants in each cell were
trimmed to one plant per cell.
0.6
0.4
•After seven days, one 16-cell plant bock was
designated to be a control group to be watered with
freshwater, while the other cell was designated the
experimental group to be watered with 1.0% salt water.
•After fourteen days, plant heights and biomass were
measured for four plants randomly selected from each
planting block.
•Two separate t-tests were run to test the significance
of the data for plant height and biomass.
0.2
.
0
Control Group
Salt Group
Figure 3a :
Graph of the average wet biomass of Brassica Rapa. Plant body
including roots were weighed using a gram scale. The 1.0%
sodium chloride solution was shown to have a significant effect
on the mean biomass of the experimental group in comparison to
the mean biomass of the control group (p=.026).
Compared Heights Of Experimental and Control Groups
16
14
p-value =.061
t-value=-2.30
12
Figure 2a: Brassica rapa Control Group
Height (cm)
10
8
6
4
2
Figure 1: Map of the US Coastline Showing
Increasing Sea Level Rise (NOAA)
0
Control Group
Figure 2b: Brassica rapa Experimental Group
Salt Group
Figure 3b:
Graph of Heights of Experimental and Control Groups of
Brassica rapa. Plants were measured from the base of the plant
to the highest point using a ruler. The 1.0% sodium chloride
concentration was shown to have a slight but insignificant
effect on the mean plant height of the experimental group in
comparison to the mean height of the control group (p=.061).
•During the course of the experiment, data collected
indicated that Brassica rapa growth was reduced by
sodium chloride (NaCl) concentrations. The plants
watered with 1.0% NaCl water did not grow as
successfully as the control plants which were watered
with tap water.
•In this experiment the number of replicates was
reduced due to the unintentional watering of some of
the experimental plants with soap water which
adversely affected the growth of these plants.
•Salt stress affects all the major processes such as
growth, photosynthesis, protein synthesis, and energy
and lipid metabolism (Parida and Das 2004).
• In respect to plant growth, plants’ immediate
response to increased salinity levels is a reduction in
leaf surface area and eventual cessation of leaf
expansion (Wang and Nil 2000).
• As a result, light interception is decreased and the
photosynthesis rate is slowed consequently reducing
plant biomass.
•Photosynthesis rates have also been observed to slow
in plants as a result of increased salinity due to
significant reduction in CO2 assimilation rate and
stomatal conductance and inhibition of the electron
transport chain( Reddy et al. 1992).
•Water uptake, water retention, and transpiration rate
decrease in some plants as a result of sodium chloride
induced stress (Chaudhuri and Choudhuri, 1997). Each
of these factors may have potentially resulted in the
reduced biomass of the Brassica rapa experimental
plants.
•As the polar ice caps melt and sea levels continue to
rise, coastal areas will continue to be inundated with
increasing concentrations of salt. It is important to
determine whether these plants will be able to
withstand these harsher conditions and if so, to what
extent.
•A potential future experiment would be to study further
the effects of increased salt water concentrations on
leaf surface area and stomatal conductance. These
results would help determine the magnitude of the
References
reduction of leaf surface
area as well as decrease of
stomatal conductance in response to salinity induced
stress.
1. Allakhverdiev, S.I., Sakamoto, A., Nishiyama, Y., Inaba, M., Murata, N., 2000b. Ionic and osmotic effects of NaCl-induced inactivation of
photosystems I and II in Synechococcus sp. Plant Physiol. 123, 1047–1056.
2. Chaudhuri, K., Choudhuri, M.A., 1997. Effect of short-term NaCl stress on water relations and gas exchange of two jute species. Biol. Plant. 40,
373–380.
3. Kurban, H., Saneoka, H., Nehira, K., Adilla, R., Premachandra, G.S., Fujita, K., 1999. Effect of salinity on growth, photosynthesis and mineral
composition in leguminous plant Alhagi pseudoalhagi (Bieb.). Soil Sci. Plant Nutr. 45, 851–862.
4. Parida, A.K., Das, A.B., 2005. Salt tolerance and salinity effects on plants: a review. Ecotoxicology and Environmental Safety. 60, 324-329.
5. Rajesh, A., Arumugam, R., Venkatesalu, V., 1998. Growth and photosynthetic characterics of Ceriops roxburghiana under NaCl stress.
Photosynthetica 35, 285–287.
6. Reddy, M.P., Sanish, S., Iyengar, E.R.R., 1992. Photosynthetic studies and compartmentation of ions in different tissues of Salicornia brachiata
Roxb. under saline conditions. Photosynthetica 26, 173–179.
7. Wang, Y., Nil, N., 2000. Changes in chlorophyll, ribulose biphosphate carboxylase–oxygenase, glycine betaine content, photosynthesis and
transpiration in Amaranthus tricolor leaves during salt stress.J. Hortic. Sci. Biotechnol. 75, 623–627.