Qualitative research on the sun and plants

The purpose of this qualitative research is to discover how light from the sun affects how plants grow. This has been proven by scientists that living things need sunlight to live. In this regard, the study was carried out to determine if this theory affects plants too. The intensity of light needed for growth depends on the type of plant and different experiments were conducted on the different plants; including aquatic and terrestrial plants. All observations were noted down and analyzed to form the basis of the conclusions for this research.
Plants of different sizes were used in this experiment. Some were placed in areas where they had access to direct sunlight while the rest were put in areas where there was no sunlight. This was done to find out how both reacted to the conditions they were put in and if it had any impact on their growth. The results achieved were recorded and interpreted to form the conclusion of the experiment.

Chapter 1: Introduction
1.1 Background to the study
There are different types of plants. Some grow on land while others grow in water. Some plants are grown in farms and fields while others are grown indoors form example potted plants. Some have direct access to sunlight while others have limited access to the sunlight because they are hindered by the location on which they are growing, be it indoors or underwater. This made me curious and prompted me to ask myself ‘How does sunlight impact the growth of plants?
Curiosity and the eagerness to find out how the sun impacts the growth of various plants led me to conduct this research.
Plant physiology

Plants inhabit a better part of the earth. Some grow on land while others inside water bodies. It has been proven by scientists that Sunlight rays are vital for growth of all living organisms. Humans feel the impact of the sun through their skin which absorbs the light that indirectly influences their growth through the vitamins provided by the sun.
Plants have no skin. Instead they have leaves, barks and stems that are used to absorb sunlight. This research was carried out to prove if indeed the sun has any impact on the growth of the plants.
Plants have the ability to grow in different intensities of light; from full sun light, to shade and in total darkness. Most scientists have different ideas concerning this. Some believe that sunlight negatively impacts growth in plants. This belief is so common that it has become almost globally accepted in the world of plant physiology. It has been used to explain various types of phototropism as well as the variable growth rates of etiolated and unetiolated plants.
Test for phototropism in plants
Plants growth region is mainly the shoot which contains auxins which are responsible for the shoot growing towards light or away from light. When auxins are exposed to sunlight they move to the lower side of the shoot where they stimulate growth leading to the formation of a convex shape by the shoot and thus the shoot grows towards the light source. Like many widely accepted physiological beliefs, the constraining effect of sunlight was made popular by Sachs who conducted some of the early experiments demonstrating that plants may are also able to grow away from light. He documented the several secondary effects of light on growth.

Starch test on plants
The leaf to be tested is submerged in a container of boiling water to break the starch granules for some few minutes. It is then taken out of the boiling water and immersed in a boiling tube containing phenolphthalein to discolour the leaf. Finally, the leaf is placed on a white tile and drops of iodine are added on it. If the colour turns to blue black, it indicates presence of starch and when the brown colour persists it indicates absence of starch.
1.2 Statement of the problem
Different plants have different light intensities and need different amounts of light. Some grow in fair amount of light, others grow in total darkness while some can do with just any amount of light available. This research is meant to find out if the sun and light in general has got any impact whether positive or negative on the growth of plants. The study will reveal how plants react to both absence and presence of sun light. By exposing the plants to both presence and absence of sunlight, I will be able to determine whether sunlight has any impact on plants’ growth or not.

1.3 Purpose of the research
The purpose of this research project is to determine if there is any impact on how plants grow in the presence of sunlight and in the absence of it. It is meant to find out how plants grow based on their exposure to light and the lack of it
1.4 objectives of the study
The research was guided by the following objectives;
(i) To examine the influence of light in the growth of plants
(ii)to explore the impacts of light on all types of plants
(iii)To determine how plants react to both absence and presence of light
1.5 Research questions
(i)Can plants grow without sunlight?
(ii)Is sunlight really important for the growth of plants?
(iii)Do all types of plants both aquatic and land impacted by the availability of sunlight?
1.6 Significance of the research
The research shows the extent at which plants need sunlight for their growth. It highlights how plants react to several conditions of light and lack of it (). The study may be of benefit to science students interested in knowing how sunlight impacts the growth of plants. It can also be of importance to farmers and also people who grow plants like flowers just for fun.

Chapter 2: Literature review
(Thut and Loomis, 1944) State in their research that plants can grow in different light intensities ranging from full light from the sun to darkness. They show characteristics and well known differences in growth and development. Much of the effect that light has on plants is summed up in the phrase ‘light hinders growth’ which has become too common in the world of plant physiology study.
Sachs (1872) argues that light has an inhibiting effect on plants.He states that plants have the capability to grow in darkness although they will not be as healthy as those that have access to light. Sach conducted several experiments and he recognized some of the several effects of light on growth which directly inhibited growth through some processes on the growing regions.
Several other research workers also agree with the notion that light affects growth. H. Popp (1926), K. Prantle (1873) agree with Sach even though not wholeheartedly that light can either have a negative or positive impact on the growth of plants.
F. Brown (1935) stressed the use of ultra violet in checking the growth of plants. Brown and Popp found in their research that palm fronds stopped momentarily soon after sunrise and did not resume until near sunset. Growth resumed within minutes in the case that the plants were covered during the day but was slightly hindered if under cover or at night.
W.E Loomis (1932) who was working with potted corn plants in a greenhouse suggests that the elongation of the plant’s leaves was controlled by the temperature and the supply of water within the plant itself and not directly affected by light. He states that temperature is normally associated with radiation but the water levels within the tissues of the plant have a propensity to be negatively correlated. The greenhouse’s glass reduced the ultraviolet rays of the sun by sheltering out the shorter and stronger wavelengths.

J.A. Prescott (1921) on the other hand found that corn in the field in Alexandria Egypt also made its greatest growth after dawn in the morning and dusk in the evening, with a mid day decline that was accentuated by a drop in the percentage of dampness in the soil. Thus there is a moderate general consensus among several botanical investigators that sunlight is not directly inhibiting for plant growth though the conclusion is not unanimous.

Thut and Loomis (1944) conducted an experiment where a certain strain of open pollinated corn plants (Zea mays) was grown on a rich deep black fertile loam soil in an agricultural research station. The increase in height in height of the leaves was then monitored. A growth of ten to fifteen centimetres was recorded. This measurement included size increase caused by cell division and elongation at the base of the leaf, in the sheath of the leaf and in the diverse numbers of stretched internodes on the lower side of the leaf.

Previous measurements however, showed that likeminded results could be obtained from two or three younger leaves of a single plant. Measurements were then made by tying a ring with tape to the leaf that was supposed to be measured. Auxonemeter pins which were balanced to an even pull of fifteen grams were then hooked into the rings and the elongated reading was five to one on a meter scale. The auxonemeter were then removed when making the readings to evade disturbance by strong breeze. Moisture readings were made with a sling psychrometer and the light readings were made with a device for measuring sunlight. The device is called sunlightemeter. Hygrothermograph records were then obtained from reading a recording instrument in the farm lands to check and complement the direct readings. In most of the experiments with both corn and other plants, readings were taken at two hour intervals during the entire experiment. Growth of the plants was calculated in the form of millimetres per hour for an estimation of six or more plants and recorded as the rate of growth at the period. Light, humidity, temperature and humidity readings were also taken.

Chapter 3: Methodology
For this research, data was taken from actual experiments which were carried out to establish the results which were later analysed to get the conclusion to this research. I carried out experiments using plants to ascertain if sunlight impacts the growth of plants.
Experiment using a bean plant
Materials used
Dark polythene bag, cello tape, frustum, scalpel, boiling tube, Bunsen burner, iodine solution, bean plants, white tile, container with an opening and spade.
Method and procedure
-Picked the frustums filled them with soil using the spade and planted different bean plants each plant in its own frustum.
-Placed one bean plant in the field where there is abundant sunlight. Placed the second bean plant in the same field but one of the leaves was covered using the dark polythene. The plants were left for a whole day at the sun. Later one leaf from the plant without black polythene bag. The leaf was dipped in boiling water in a beaker for three minutes .It was later placed dipped in a boiling tube containing phenolphthalein and dipped in a water bath. The leaf was lastly placed on a white tile and two drops of iodine solution placed on the leaf and the brown colour of iodine turned to blue-black.
The leaf covered with the black polythene bag was picked and dipped in a beaker with boiling water for two minutes .Later, it was dipped in a boiling tube containing phenolphthalein and dipped in a water bath. Lastly the leaf was placed on a white tile and

Drops of iodine solution added on it where the brown colour of iodine remained brown.

A bean plant growing on a frustum was covered with another container with a small aperture allowing sun light penetration and the plant placed in the open field .The plant was left for fourteen days and it was observed that the shoot of the bean plant grew towards the aperture.