Abstract
Germination is a process that combines several factors of growth among them oxygen, water and other ingredients for growth. A successful germination of seeds requires a favorable life supporting environment. To achieve this, plastic bags with ten bean seeds each were prepared and four different concentrations of KCL solution were added as follows. The first Plastic bag had zero percent of KCL and contained distilled water only while the others contained 0.1M, 0.25M, 0.4M, and 0.5 M respectively.
In this experiment, the impact of increasing the concentration of KCL on the seeds germination process was tested. The prediction that saline solution will have an inhibiting effect on the bean seeds will be verified.
After a 7-day observation period of the germinated seeds, rates were recorded. The dish with little or no KCL solution had relatively large number of germinated seeds while the rest had a smaller number and took longer. These results were analyzed in tabular and graphical formats for the ease of comparisons. The conclusion showed that an increase in salinity levels affected the germination rates of mung bean seeds.
In light of the above, the experiment proved that the increase of KCL solution inhibits germination rate of seeds. This research would be used by other scholars and researchers in enhancing agricultural research in this field and design, and implementation of better farming techniques.
Introduction
Salt is known to impact the germination rates. Absorption of water in the cells requires a differential concentration between the cells and the external environment (Ahmad and Prasad 15). Studies have shown that saline environment affects the plants by limiting their ability to absorb nutrients and most importantly water. This means that saline environments affect the plant at all the stages, from germination to maturity. Plants exposed to salinity for a longer period do not survive long after germination occured. However, the saline conditions might be too harsh to support growth. This experiment will only test the germination rates and will observe the seeds sprout.
This experiment is designed to test both germination rate and speed rate when seeds are exposed to a saline environment. It will prove that when the solution of KCL is increased, the germination rates of the bean seed will reduce. This experiment was supposed to confirm that growth speed of seeds in saline concentrations is inhibited. The samples are subjected to similar conditions in terms of temperature, light, and oxygen. That meant that those conditions did not affect the results of the experiment. In various samples, the results were used, and the changes in the growth were recorded for analysis.
According to Khan, salinity inhibits growth as it affects the water absorption ability of plants (58). These effects were observed in the germination stage. Previous researches done by scholars have shown similar results, and researchers conducted an experiment to verify these claims. The saline stress reduced the turgor pressure, which reduced the rate of elongation of cells, effectively translating it to low rates of germination.
Germination
When seeds are dry, they are known to be in a dormancy condition. The resumption of growth triggered by favorable environmental conditions is referred to as germination (Ahmad and Prasad 15). Germination starts by the sprouting of the root and the breaking of the seed’s cover. In environments that are not conducive for the growth of a particular seed, the seed may either fail to germinate or take a longer time to sprout. In favorable conditions, the seed is expected to germinate within two days.
It was noted that different plants react differently with different temperatures and salinity. The decrease in plant growth, stomata conductance, leaf area, and transpiration rate are some of the consequences of high salt presence (Gutterman 165). In saline concentrated environment, the seeds are unable to absorb water and thus inhibiting germination (Parida and Das 423).
For a conclusive growth conclusion, a seed must be observed from germination stage to maturity. But this experiment is only designed to show the impact of salt on the germination process and how the plants adjust their osmotic capabilities to survive such environments.
Osmosis
Osmosis is a free movement of water from a low concentration to a higher concentration through a membrane (Ahmad and Prasad 15). Water-soluble move from highly concentrated to a lowly concentrated is trying to achieve an equilibrium condition.
Salinity distorts this equilibrium and as a result, osmotic pressure increases. This implies that the saline conditions hinder germination by reducing the amount of water that enters the seed to trigger germination. The more the saline condition the more time it requires from the seeds to absorb enough water for the germination process to begin. The entry of saline solution into the seed reduces the osmosis process by reducing the seed’s ability to defuse water into the cells and thus more time is required to trigger germination. In light of this, the hypothesis that seeds in high concentration of KCL salt will have the lowest germination rates was tested. The higher the salinity levels the more the osmotic pressure required in triggering germination.
Methods and materials
The experiment is aimed at determining the role of osmosis in the germination of bean seeds. The research used four solutions of different KCL concentrations to examine how the different concentration levels affected the germination of bean seeds (Ahmad and Prasad 15).
The experiment required several components; distilled water, mung bean seeds, two towels, Plastic bags and four concentrations of KCL solutions. The solutions were to be in concentrations of 0.1M, 0.25M, 0.4M, and 0.5M of KCL in separate containers. All conditions were similar except for the difference in concentration levels.
The towel was folded in two, and the seeds were placed on it. In each Plastic bag, seeds were put in, and the towels were put into the different concentrations. Then put into separate Plastic bags containing seeds. The dishes were labeled as with their respective concentration levels. They were then placed near a light source and in this case near the window. The room temperature was about 20 to 23.5 degrees Celsius when the experiment was done and remained in stable level throughout the experiment period. The progress of the germination process characterized by sprouting was done each day for a period of one week with the germination lengths measured and recorded in tabular form as shown in table 1.1A below. Also, a summary of the germination rate was calculated and was also shown.
Results of the Experiment
They observed that the germination rate for bean seeds differed depending on the environment in which they were exposed. The seeds in distilled water and various concentrations of KCL germinated in different rates throughout the week. A calculation of the percentages (%) of the germinating seeds in the various samples and presented them in table form as shown in table 1.1 A below. More germinating seeds were observed in the distilled water only followed by the 0.1mm concentration, and there were zero observations in the samples with a high concentration of KCL.
After seven days, all the bean seeds in distilled water had germinated; 0.1 M recorded a 74.6% germination rate, while 73.3% of the seeds in 0.25 M KCL had already germinated. For 0.4 M and 0.5 M KCL concentration, the germination rate was 16.25% and 1.67% respectively.
Table 1.1A: Impact of the Solutions to Germination (bean seeds)
This diagram shows and proves that the allegation that saline environment is unfavorable to mung bean seed is seen here. The adaptation of certain plants to salt stress influences the germination and growth rates. In the case of mung bean seeds, their adaptation abilities to germinate in all the four different KCL concentrations were observed.
Discussion
The prediction that saline solution will have an inhibiting effect on the bean seeds and that seeds in a concentrated KCL concentration will have a lower germination rate and the results of this experiment proved it. As the above diagrams shows, the results were consistent with the research done by other researchers. The findings are consistent with studies done by Gutterman (165) who suggested that non-saline conditions lead to higher germination rates as opposed to saline ones.
In other research done to test the effects of other salts of the germination process the results were similar. Salts like K2SO4, Na2HCO3, NaCl, and CaCl2 are being observed to inhibit growth of plants (Baskin and Baskin 67). In other research testing MgCl2, the results were also similar (Gutterman 165). This shows that the hypothesis that the germination rate of mung seeds growth will be affected by salinity is confirmed.
The bean seeds have cellular walls that resist the severity of the turgor pressure. Before germination, they were in a state of dormancy characterized by zero growth (Baskin and Baskin 67). Similarly, zero percentage growths was observed after the first day. The observation was applicable to all solutions (Table 1.1A). The water got into the seeds through osmosis process. The results showed that the de-ionized water and 0.1 M KCL solution are hypotonic relative to the seed cellular structure.
In the 0.5 M KCL solution, the seeds’ environment was highly hypertonic as compared to that inside the cells. This result means that they were unable to absorb any water and thus took more time to absorb it due to the difference in the concentration levels. The saline stress reduced the turgor pressure, which reduced the rate of elongation of cells, effectively translating to low rates of germination. Observations show that the rate of germination reduced proportionately as the KCL concentration increased.
Osmotic pressure can also have an impact on the number of seeds that germinated. Observation showed that the seeds in saline conditions took more time to absorb water into their cells because of the concentration of KCL in their cells and thus were unable to absorb enough water for germination. The seeds in 0.5M concentration took more days to absorb enough water to enable germination. This also shows that the seeds had to fight the osmotic pressure to absorb water to facilitate germination.
Conclusion
It is clear that the concentration level of KCL solution inhibits germination. From the experiment the conclusion that KCL inhibits growth can be made. It, therefore, indicates that the concentration of the plant should be lesser that the concentration of the soil to ensure the efficiency of this process. The water cannot cross the membranes of the plants and thus the plants are unable to absorb these essential components of growth (Ahmad and Prasad 15).
The above observations differed in the various samples, and this was because of the salinity as all the other growth factors were similar in all the samples. This leads us to conclude that soil salinity can result in stunted growth when the seeds or plants do not adapt to these types of conditions. Salty soils can only support seeds designed to survive these conditions and vice versa. It showed that mung seeds cannot survive saline soils. Furthermore, these data supported the hypothesis that high concentration of KCL decreases the germination rate of bean seeds.
Works Cited
Ahmad, Parvaiz, and Prasad Nihar. Abiotic Stress Responses in Plants: Metabolism, Productivity and Sustainability. New York: Springer, 2012. Print.
Baskin, Carol, and Jerry Baskin. Seeds: ecology, biogeography, and evolution of dormancy and germination. San Diego, Calif.: Academic Press, 1998. Print.
Gutterman, Yitzchak. Survival Strategies of Annual Desert Plants. Berlin: Springer, 2002. Print.
Khan, Nafees. Phytohormones and Abiotic Stress Tolerance in Plants. Heidelberg: Springer, 2012. Print.
Parida, Kate, and Andrew Das. “Salt tolerance and salinity effects on plants.” A review of Ecotox Environ Safe 60 (2005): 324-349. Print.