The literature review on nutrient deficiencies in tomatoes shows that the complete treatment plants are the healthiest out of all of the treatments. We compared the weight and SCC of the plants and leaf blades of plants using complete, -N, -P, and distilled water treatments. We measured the weight and SCC by growing the plants for 4 weeks, weighing the leaf blades after harvesting the tomato plants, and extracting chlorophyll out of 5g of leaf blades. There was not a significant difference between the complete and distilled water treatments in both weight or SCC. In fact, there was not a significant difference between the complete and both the -N and -P treatments in weight or SCC. Unfortunately, the chi-square analysis results do not support a relationship between having the usual amount of nitrogen and phosphorus in a plant and the health of a plant.
Introduction
As stated in Kosinski’s literature review, nutrient deficiencies found in plants can cause necrosis of plant parts, stunted growth, and chlorosis. In this tomato plant experiment, nitrogen and phosphorus are mobile elements (Kosinski, 2018). This means that nitrogen and phosphorus can change their number of copies or their location (Macmillan Publishers Limited, 2018). We used tomatoes to measure nutrient deficiency because they are easy to grow, and the plants easily show nutrient deficiencies (Kosinski, 2018). The element that is commonly deficient in soil is nitrogen (Kosinski, 2018). This is because plants can only use fixed nitrogen (Kosinski, 2018). Deficiency in this element causes yellowing of older leaves, delayed vegetative growth, acceleration in flowering, reduced fruit production, and stunted growth (Kosinski, 2018). The yellowing of older leaves happens because chlorophyll formation needs nitrogen, but it can easily change locations, so the older leaves are left without nitrogen (Kosinski, 2018). Lack of nitrogen causes acceleration in flowering and reduced fruit production by delaying cytokinin synthesis and speed up abscisic acid synthesis (Kosinski, 2018). You can tell if the tomato plant is suffering from nutrient deficiency by looking at its stem and leaves. The plant’s stem will be stiff, upright, and thin (Kosinski, 2018). The plant’s leaves will be small and yellow if it is lacking nitrogen (Kosinski, 2018). The second most common nutrient that soil lacks is phosphorus (Kosinski, 2018). Lack of phosphorus causes increased respiration rates, stunt in growth, and delayed leaf growth (Kosinski, 2018). Figuring out whether or not a plant suffers from phosphorus deficiency is very difficult because since the leaves are very green, it looks like the plant is very healthy (Kosinski, 2018). The only way you can spot phosphorus deficiency in a plant is if you have a plant that is a control to compare it to (Bergmann, 1992). Tomato plants that lack phosphorus usually are a purple color on the bottom of their leaves, dark green young leaves, yellow older leaves, curled leaflets, stems that are purple and thin, and small fruit production (Kosinski, 2018). The leaves on the tomato plant will also have a bluish-green tint if it suffers from phosphorus deficiency (Dore, 2008). Plants that are grown in distilled water show more symptoms of nitrogen deficiency than phosphorus deficiency (Kosinski, 2018). Distilled water plants usually have stunted growth and chlorosis (Kosinski, 2018). The results of growing a tomato plant using only distilled water shows two things about what is vital for a plant to survive. It shows that nitrogen is the most important element found in plants, and that means that if the plant is lacking nitrogen, then the plant does not really need the other nutrients as much as it usually does and so you will not really see the symptoms of other nutrient deficiencies (Kosinski, 2018).
Our first null hypothesis was that there would not be a difference in weight or SCC between the complete treatment and the distilled water treatment. Another null hypothesis was that the weight and the SCC of a plant would be the same when either using the complete or the treatment lacking nitrogen. Lastly, our last null hypothesis was that there would not be a difference in weight or SCC between the complete treatment and the treatment lacking phosphorus. My specific lab table was assigned to observe and take care of plants that were using the distilled water treatment.
Materials and Methods
Using the Plant Nutrient Deficiency OMP provided on the Biology 110 website, my table was assigned the distilled water treatment and we ran an unpaired test. First, we randomly chose one plant from the flats and removed the soil off of the roots using a washtub. We then placed the plant in a beaker full of distilled water. Afterwards, we planted the plant in a hydroponic recirculator that pumps nutrient deficient solution past the roots of the plant. In order to plant the plants in the hydroponic recirculator, we had to clean the plastic cup that it was going to go in, use an inoculating loop to make sure the roots go through the slots, and fill the cup with clay pellets to make sure that the plant stands upright. After four weeks had passed, we started the harvesting process. We removed our plants from the pots and dumped the pellets into the bucket that was meant for used pellets. Next, we weighed the whole plant in the weigh boat. Afterwards, we removed all of the leaf blades and threw away the rest of the plant. We then weighed the leaf blades and selected the 5 g of leaf blades that we were going to extract chlorophyll from. Then, we calculated the SCC of the plant and recorded it in the data table on the podium computer.
Results
Table 1. Complete vs. Distilled Water Plants
Variable Mean of Complete Mean of Distilled Water Chi-Square P-Value
Weight (g) 3.184 3.009 0.227 0.634
SCC (mg/g) 0.632 0.967 0.00 1.00
Table 1 shows that the average weight of the complete treatment was 3.184 g and the average weight of the distilled water treatment was 3.009 g. It also shows that the average SCC of the complete treatment was 0.632 mg/g and the average SCC of the distilled water treatment was 0.967 mg/g.
Table 2. Complete vs. Nitrogen Deficient Plants
Variable Mean of Complete Mean of (-N) Chi-Square P-Value
Weight (g) 3.184 2.918 0.045 0.831
SCC (mg/g) 0.632 0.573 3.273 0.0704
Table 2 shows that the average weight of the treatment lacking nitrogen was 2.918 g and that the average SCC of the same treatment was 0.573 mg/g. It also shows the average weight and SCC of the complete treatment again.
Table 3. Complete vs. Phosphorus Deficient Plants
Variable Mean of Complete Mean of (-P) Chi-Square P-Value
Weight (g) 3.184 3.25 0.045 0.831
SCC (mg/g) 0.632 1.749 1.455 0.228
Table 3 shows that the average weight of the treatment lacking phosphorus was 3.25 g and that the average SCC of the same treatment was 1.749 mg/g. It also shows the average weight and SCC of the complete treatment.
Discussion
Table 1 shows that the plants of the complete treatment weighed more than the plants from the distilled water treatment and that the leaf blades from the distilled water treatment had a higher SCC. Since both of the p-values were more than 0.05, we fail to reject the null hypothesis that states that there will not be a difference in the weight and the SCC of the complete and distilled water treatments. Table 2 also shows that the plants and leaf blades of the complete treatment weighed more and had a higher SCC than the plants and leaf blades from the nitrogen deficient plants. Since both of the p-values were also more than 0.05, we fail to reject the null hypothesis that states that the weight and the SCC of a plant would be the same when either using the complete treatment or the treatment lacking nitrogen. Table 3 shows that the phosphorus deficient plants and leaf blades actually weigh more and have a higher SCC than the plants and leaf blades using the complete treatment. However, since both of the p-values were more than 0.05, we fail to reject the null hypothesis that states that there will not be a difference in the weight and SCC of the complete and phosphorus deficient treatments.
Picture 1. This picture is a picture of the distilled water treatment plants before harvesting day.
In this picture, you can see the symptoms of nitrogen deficiency clearly. The growth of the plants was stunted, and you can see the yellowing of the leaves (chlorosis). This means that main deficiency found in the distilled water treatment was nitrogen deficiency, which supports the results of this experiment performed by previous lab sections.
Picture 2. This is a picture of the -N treatment plants before harvesting day.
As shown in Picture 2, chlorosis has begun, and their growth has been stunted. The distilled water treatment is very similar to this treatment, which further proves that the main deficiency that can be seen in plants using just distilled water is nitrogen deficiency.
Picture 3. This is a picture of the complete treatment before harvesting day.
In this picture, you can see that the completes look very healthy. Their leaves are very green, and their stems are very thick. The plants are also taller than all of the other treatments. They are so long that the plants are starting to bend over.
Picture 4. This is a picture of the -P treatment before harvesting day.
In Picture 4, the -P treatment looks very similar to the complete treatment. However, you can see that the -P treatment plants are a little shorter than the completes. Furthermore, you cannot really see the phosphorus deficiency symptoms in these plants.
Unfortunately, our results could have been corrupted because we could have done something wrong while extracting the chlorophyll during the harvesting process. Moreover, there was deviation between the plants that were under the same treatment. This could have caused the chi-square analysis to show that the results were non-significant and could not disprove the null hypothesis. The reason why the chi-square analysis shows that the results are non-significant is because chi-square only uses values that above or below the median value. This means that the two treatments that are being compared could both be above the median value and in the chi-square analysis they would be considered to be the same. It would not matter that one treatment could weigh significantly more than the other.
In order to get more accurate results, we should have treated the plants better while planting them and made sure that we did not over-cleanse the roots.
A question that could be investigated is the effect that other nutrient or element deficiencies, such as potassium deficiency, have on tomato plants. Another future investigation that could be conducted is the effect that nitrogen and phosphorus deficiencies have on other plants like pea plants.
2018-4-27-1524799631