Effects of Sugar on Plant Growth

Generally, water is an essential requirement for plant growth. But what happens when sugar is added to water, and then the mixture is sprinkled to a growing plant? Providing an answer to this question could help suggest a better way of growing plants and possibly improve yield. In our lab experiment, however, we investigated the effects of adding table sugar to plant water. In nature, plants manufacture their sugars during photosynthesis. One could automatically think to add sugar to water may result in growth, but our experiment did not follow that instead plants were infested with buds and finally died.

Introduction

Plants need water, sunlight, and nutrients to grow. Alteration of these components in terms quality and quantity could adversely affect the plant's ability to carry out photosynthesis. Water is a crucial component of plant life transported from the roots to other parts of the plants by the xylem. The significant roles played by water in plants include photosynthesis and creating cell tension giving the plants their definite shape. Additionally, water to some extent acts as storage of minerals such calcium which is equally essential for plants growth. The only way for the plants to access minerals is through water uptake by osmosis.

In plants, growth can be determined by many factors such as dry weight, plant height, and general leaf appearance (Ghoulam et al. 2002). Quality of sunlight the plant receives has a significant effect on the growth of the plant. Plants growing in extremely shaded environments may display a whitish shoot and slender due to the inability in carrying out photosynthesis even if other factors for growth are available. In the presence of the quality light, plants initiate photosynthesis involving the breaking of water molecules producing hydrogen atoms which later in the dark stage combine with carbon (IV) oxide to form simple sugars such as the carbohydrates.

The purpose of this experiment was to determine the effects of sugar on plants growth. The test was carried out in about one and half month. During the investigation, a two group model was designed. Control experiment formed one group where plants were grown and watered using the regular water (Lastdrager et al. 2014). Control experiments help in determining the change in the typical growth pattern through comparison of heights recorded at the beginning and end of the test. Our primary hypothesis was that sugars in the water would not affect the growth of plants.

Method

Four small pots were filled with the garden soil and kidney bean seeds planted in each of them. Two control beakers were named A and B. The experimental groups were marked C and D. Two tablespoons of brown sugar was added to 240ml of water to prepare the solution in a different beaker, and the mixture poured on to the experimental glasses C and D. The control small pots A and B were filled with pure water. The four small pots were watered with the respective liquids at an interval of four days using constant amount each fluid. The growth of plants in the two groups was monitored and their heights measured and recorded as an indication of growth and development. The growth measurements were taken by use of a string and a ruler. The plants were closely supervised, and watering was adjusted depending on the behavior displayed by the groups. The t-test and f-test were used to analyze the difference between the mean of the independent variables.

Results

Days Recorded

Average length of experimental samples C and D

Average length of control A and B

12th

October

0 cm

0 cm

2nd

November

4.5 cm

4.0 cm

9th

November

9.2 cm

9.4 cm

20th

November

0 cm (dried up)

0 cm (dried up)

Table 1 showing the average heights of seedlings measured on a weekly basis.

The measurement recorded on date 12th October did not give any reading since the seeds were yet to germinate. On date 2nd November, seedlings eventually germinated and the experimental seedlings recorded a faster growth compared to the control seedlings growing on pure water. Finally, at the end of the experiment, the seedlings control group registered an overall increased length compared to the group raised on sugar water. The seedlings growing on sugar water developed some buds on date 16th November, and the effect was spread to the control group resulting in the death of all the plants.

Analyzing the f-test which is s2/s1 where s2 represent the standard deviation of sample A and B and s1 for sample C and D. f = 0.4/0.1 = 4.0 since the calculated f-test is higher than the critical F, the null hypothesis is dropped proving our hypothesis that sugar present in water did not affect plant growth.

Discussion

The experiment was left to run for about a month and a half. During this period, the plants in the control group dominated concerning the shoot length resulting in an overall highest shoot length recorded as shown in table 1 before they all dried up due to bud infestation on experimental group. However, the plants on water sugar seemed to be more healthy and robust but our experiment aimed at determining growth based on shoot length. At the beginning of the test, plants showed a slow rate of growth because the seedlings needed some time to adapt and absorb nutrients in their environment (Sadeghian and Yavari 2004). In this regard, it was observed that plants on the salt water adopted faster resulting in the higher height recorded after the first two weeks of the experiment. The final higher figure in the control plants, therefore, confirmed our hypothesis which stated that sugar solution would not have a significant effect on the growth of plants.

The plants growing in the sugar solution were attacked by a strange bud which resulted in their death after sometimes. The sugar in the water encouraged the microbial growth. Microorganisms feed on sugar as it is their preferred substrate. As a result, the rate of growth of the microbes increased to a level affecting the growth of microorganisms. It should be remembered that the soil acts as a home of billions of different bacteria. The sugar solution facilitates the growth of these microbes resulting to development of unknown buds feeding of the plant sap causing the observed death.

Plants manufacture their sugars during photosynthesis. Plant roots are only adapted to absorb water and mineral salts from the soil to be used in food making process and other functions (Watanabe et al. 2000). The root hair cells do not incorporate the sugars from the ground. However, the presence of the sugars in the soil may result in the alteration of the osmotic potential of the surrounding resulting in water loss from the plant's cells to neutralize the higher sugar solution from the environment. The water loss may lead to loss of shape of cells followed by plants falling down and finally dying.

Conclusion

Sugar availability in the soil creates a hypertonic situation which may result in plant death. Care should be taken while measuring the height and other parameters of growth such as the dry mass should be used while determining plant growth. Further research should be done on effects of sugar as experimental plants appeared healthy.

Work Cited

Ghoulam, Cherki, Ahmed Foursy, and Khalid Fares. "Effects of salt stress on growth, inorganic ions and proline accumulation in relation to osmotic adjustment in five sugar beet cultivars." Environmental and experimental Botany

47.1 (2002): 39-50.

Lastdrager, Jeroen, Johannes Hanson, and Sjef Smeekens. "Sugar signals and the control of plant growth and development." Journal of experimental botany

65.3 (2014): 799-807.

Sadeghian, S. Y., and N. Yavari. "Effect of water‐deficit stress on germination and early seedling growth in sugar beet." Journal of Agronomy and Crop Science 190.2 (2004): 138-144.

Watanabe, Shin, et al. "Effects of saline and osmotic stress on proline and sugar accumulation in Populus euphratica in vitro." Plant Cell, Tissue and Organ Culture 63.3 (2000): 199.