Proceeding of 6th ICGRC
2015
Salt Tolerance of Several Aquatic Plants
Munifatul Izzati1
1
Depertement of Biology, Diponegoro University, Indonesia
Corresponding author: [email protected]
Abstract
Aquatic plant has an important role in aquaculture management. We interested in studying their salt tolerance to give guidance in
choosing the right species for better management. In preliminary study we test 20 species to test their survival on different level
of salinity. Collected sample were washed, weighed and placed in 100 L of different level salinity of water (5 ppt, 10 ppt, 15 ppt,
20 ppt, 25 ppt and 30 ppt). Their survival was indicated by their color and freshness of remaining biomass. Their growth rate in
different salinity level was also studied for only three species, Hydrilla verticillata, Ceratophyllum demersum and Salvinia
molesta, as these three species were the most tolerant to salinity change. Measurement of their growth respond to salinity change,
was done by growing plant biomass in fresh water, and then gradually added with salt to increase water salinity to level of 2 ppt
each week. Results indicated that, Pistia stratiotes and Lemna minor are most tolerant to salinity. This two aquatic plant species
were survives in range of salinity from 5 ppt to 15 ppt. Chaetomorpha is the most tolerant to salinity range from 0 ppt to 20 ppt.
From marine alga, Gracilaria verrucosa is the most tolerant to salinity of 10 ppt to 35 ppt. In studying the growth rate, Hydrilla
verticillata give the best performance in adaptation to salinity change. The species that has better adaptation to salinity change
will be to be used in aquaculture management. It is recommended that, in close to fresh water, Hydrilla and Pistia will give the
best candidate for aquaculture management. Chaetomorpha the best for either fresh or brackish water, while Gracilaria is
recommended to be used for aquaculture management in water close to high salinity to moderate one.
Keywords: Aquatic plant; Gracilaria; Hydrilla; Lemna; salt; tolerance
1. Introduction
The crucial role of aquatic plants, such as in producing oxygen, and pollution removal in aquatic ecosystem has
led to be used in aquacultures management. The present of aquatic plant affect directly on biomass production of
fish or shrimp. The use of aquatic plants for remediation of aquatic ecosystems has received increasing attention.
Many investigations have been conducted to proved the effectiveness of aquatic plants in remediation such as to
remove heavy metal [1], arsenic [2], copper, nickle and zink [3]. To achieve more effective function in managing
such polluted aquatic ecosystem, choosing the most suitable aquatic plant species is significantly important. Several
aquatic plant characters are used to test their effectiveness for remediation including oxygen production and
consumption, growth or photosynthesis rate and salinity tolerance. Salinity tolerance in particular is one of an
important characteristic, especially when the plant will be used to remediate the aquatic ecosystem that has a
specific salinity, such as in the brackish water. The purpose of this research is to investigate the salt tolerance of
several aquatic macrophytes in order to determine the effectiveness of using this plant species for brackish water
managements.
2. Material and Mehthods
We evaluate the salt tolerance from 20 species of aquatic plants. The plants that were used in this experiments
that were sampled from fresh water were Hydrilla verticillata, Ceratophyllum demersum, Myriophyllum spicatum,
Salvinia molesta, Pistia striates, Eichornia crassipes, Nymphoides, Elodea Canadensis, Oxalis javanica, Utriculari,
Chara vulgaris and Lemna minor. Whereas aquatic plant taken from brackish water were Najas minor, Ruppia
maritime, Chaetomorpha, Alga filament, including Gracilaria verrucosa, Ulva sp., Sargassum sp., Eucheuma
spinosum and Eucheuma cottonii.
2.1. Sample collections
Aquatic plants were collected from several areas. The fresh water aguatic plants were collected mostly from
Rawa Pening Lake located in Ambarawa district. Aquatic plants that usually live in brackish water were sample
from many area, including Pati and Kendal Regency, while macroalga were sampled from Jepara sea. These all area
is located in central java, Indonesia.
2.2. Salinity Tolerance Tests
The all tested plants were brought to the aquatic laboratory, Department of Biology, Diponegoro University for
preparation of the next research procedures. Approximately 100 gram of sample were weighed and put on 120 L
volume of aquaria (sizes: 60cm x 50cm x 40cm). Each aquarium was filled with 100L of fresh water. To enrich the
nutrient content, into each aquarium was added with 10 grams of mixed N, P and K fertilizer every week. The
various level of salinity was prepared by adding sea salt crystals to reach the desired level of salinity. The resulted
salinity of each medium was tested using refractometer. The series of salinity arranged in this research were 0 ppt
(served as controls), 5, 10, 15, 20, 25 and 30 ppt. Every salinity level in the aquarium was replicated 3 times. These
all tested aquatic plants were kept alive. Their survival and growth rate were monitored weekly, by identification of
plant freshness. This all entire experiment was done in time series according to different species. Each experimental
International Conference on Global Resource Conservation (ICGRC)
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Proceeding of 6th ICGRC
2015
series was conducted for only 2 species of aquatic plants. Every experiment was conducted for 4 weeks. Resulted
data collection was analyzed statistically by ANOVA and SPSS program.
3. Results and Discussion
3.1. Salt Tolerance Among Species
Among 20 species of investigated aquatic plants, 11 species are fresh water plants. Salt tolerance was monitored
by their freshness and color. Tolerant plant performed in green color of leave, fresh and rigid. Moderate tolerant
plant indicated by yellowish leave and weaker stem, while sensitive to salinity plant was dying and usually perished.
Survival of aquatic plants data from this study is presented in the following table.
Table 1. of Salt Tolerancece of several aquatic plant species
No
Species of Aquatic Plants
0
5
10
Salinity (ppt)
15
20
25
Fresh water Aquatic Plants
1
Hydrilla verticillata



2
Ceratophyllum demersum


3
Myriophyllum spicatum



4
Salvinia molesta



5
Pistia striotes




6
Eichornia crassipes



7
Nymphoides aquatica



8
Elodea sp.

9
Oxalis Javanica


10
Utricularia sp
11
Chara vulgaris



12
Lemna minor




Brackish Water Aquatic Plants
13
Najas minor




14
Chaetomorpha




15
Ruppia maritima


Marine Aquatic Plants
16
Gracilaria verrucosa


17
Ulva sp.
18
Sargassum sp
19
Eucheuma spinosum
20
Eucheuma cottonii
Symbol of () was indication of plant survival in each level of salinity







30
35










Result from this experiment indicated that some of fresh water aquatic plant has moderate to tolerant to salinity.
Based on data presented in Table 1, almost all of these fresh water plants survive to the level of salinity 10 ppt.
However, as much as three species, Elodea sp. Oxalis javanica and Utricularia sp., only survive at level of salinity 0
ppt. One species of aquatic plant, Pistia stratiotes survive until the level of salinity 15 ppt. Study by [4], show that
Pistia stratiotes was toxicated by the level of salinity 16 ppt. According to [5], plants respond to an increase of
salinity by reducing water intake and continued by growth reduction. It is also found that, Eichornia crassipes was
survive at the leve lof salinity was 10 ppt. Compared to research by [4] that indicated Eichornia was also toxicated at
the level of 16 ppt. Indication of toxication was chlorotic appearance on the top and aroound the edge of plants
leaves. It was also explained by [4], that Lemna minor indicated toxication at salinity higher than 16 ppt. In this
study this species was found tolerant to the level of salinity 15 ppt. From the brackish water plants, we evaluate as
much as two s pecies, i.e:, Najas and Chaetomorpha. Both species survive at salinity of 15 ppt, but Chaetomorpha
survive also at higher level salinity, 20 ppt. According to [6], Najas was one of aquatic plants that has moderate
tolerant to salinity increase. In sensitive and moderate plant respon to salinity through physiological adaptation by
changing ratio Chlorophyl/carotene content in their cell, but not in the tolerant species [6]. The same genus Najas
but differnt speies has differant respon to salinity. N. indica had moderat respond but N. graminae showed tolerant
to salinity change.
Chaetomorpha is a type of aquatic plants that has capability to adapt to wide range of salinity. It was found
frrom this study that this species survive from salinity of 0 ppt to 20 ppt. According to [7], Chaaetomorpha has
characteristic of high euhalinity and high growht rate. This aquatic plant is concluded to be a good candidate for
remediation of polluted water. From brackish water plants, Ruppia minima was indicated to have salt tolerance from
10 to 25 ppt. Evaluaton to marine plants Gracilaria was the most prospective plants to be used in wider range of
salinity. This species was susrvive ata the level of salinity from 10 ppt to 35 ppt. The other three of marine plants,
Eucheuma spinosum, Eucheuma cottonii and Sargassum were only survive at salinity of 30 ppt and 35 ppt. It can be
International Conference on Global Resource Conservation (ICGRC)
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Proceeding of 6th ICGRC
2015
concluded from this study that Pistia stratiotes is the best candidate for remediation in fresh water, Chaetomorpha
for brackish water and Gracilaria for brackish to marine water.
3.2. Adaptation to salinity changes
Evaluation of salinity adaptation over three species of fresh water aquatic plants resulted that, there was a
significat differant in respond to salinity treatmet. Hydrilla, Ceratophyllum and Salvinia were choosen as they are
the most abundance species in fresh water environment. Results indicated that, Ceratophyllum and Hydrilla perform
similar respond to gradul inrease of salinity. After treated by gradual addition of 2 ppt salinity per week, at the age
of 3 weeks, their biomass increase almost 50% (Figure 1 and 2). While Salvinia molesta indicated reduction in its
growth (Figure 3). Salvinia molesta is species with very low adaptation to gradual salinity increase in the water. It is
show from this study that this species was the most sensitive to salinity changes. Ceratophyllum was more adapted
to salinity change compared to Hydrilla, as this species has only slightly reduced at the age of 4 weeks, whereas
Hydrilla biomass reduce significantly at the age of 4 weeks. According to [8], germination and growth rate of
aquatic plant, Hydrilla was reduced by increasing salinity. Large-leaved floating species are reported to be more
sensitive to salinity, while submersed aquatic plant. Small-leaved are more tolerance than large one [4].
70
Biomass increase (gram)
65
60
C
55
S1
50
45
S2
40
S3
35
30
0
1
2
3
4
Weeks
Figure 1. Adaptation of Hydrilla verticillata to salinity changes. Note: C=Control or 100% Fresh water; S1=Salinity change to 2
ppt at 1st week; S2= Salinity change to 2 ppt at 1st and 2nd week; S3= Salinity change to 2 ppt at 1st, 2nd and 3th week
65
Biomass Increase (gram)
60
55
50
45
C
40
S1
S2
35
30
25
0
1
2
3
4
Weeks
Figure 2. Adaptation of Ceratophyllum demersum to salinity changes. Note: C=Control or 100% Fresh water; S1=Salinity change
to 2 ppt at 1st week; S2= Salinity change to 2 ppt at 1st and 2nd week; S3= Salinity change to 2 ppt at 1st, 2nd and 3th
week
International Conference on Global Resource Conservation (ICGRC)
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Proceeding of 6th ICGRC
2015
ADAPTATION OF Salvinia molesta TO SALINITY CHANGES
70
Biomsdd Increase (gram)
60
50
C
40
S1
S2
30
S3
20
10
0
1
2
3
4
Week
Figure 3. Adaptation of Salvinia molesta to salinity changes. Note: C=Control or 100% Fresh water; S1=Salinity change to 2 ppt
at 1st week; S2= Salinity change to 2 ppt at 1st and 2nd week; S3= Salinity change to 2ppt at 1st, 2nd and 3th week
4. Conclusion
Aquatic plants has a species specific respond to salinity change in their environment. Fresh water plant, Pistia
stratiotes is the most tolerant to salinity change than other tested species. The most tolerant plant from brackish
water to salinity change is Chaetomorpha, while from marine plants is Gracilaria verrucosa. This plant survive
from marine to brackish water environment. This three species has a great potensial to manage pollution loading in
the water, according to their habitat differences.
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