Effect of Light Intensity on Growth of Plants - Research Paper Example

Effect of Light Intensity on Growth of Plants Effect of Light Intensity on Growth of Plants Problem ment Sunlight is widely considered to be an absolute requirement for the growth of plants as it is one of the essential factors needed for the completion of the photosynthesis process. Light intensity generally refers to the actual amount of sunlight received by plants or the degree of brightness to which the plants are exposed to light, usually measured in lux (lx) and footcandle (fc). When considering light intensity, the quality that emanates from the sun is solely dependent on the season of the year. Lighting quality that falls on the plant also varies based on the shading of the plants. Generally, the rate at which plants grows in length depends on time; a plant remains actively dependent the light it receives. A number of previous researches have revealed that plants cannot produce the energy it needs to grow without sunlight (Lederman, 2006). A deficiency in the intensity of light normally results in reduced plant growth, yield and development as the low levels of solar energy may restrict photosynthesis. On the other hand, excessive light intensity also tends to have adverse effects on the plant growth as it induces rapid transpiration leading to water loss. However, different plants have different optimum light requirements. The present report discusses an experimental scientific method that was used to investigate the potential effect of light intensity on the growth of plants. Experimental Design The proposed experimental design will involve carrying out a number of steps designed to test a number of variables in order to conclusively determine the the potential effect of light intensity on the growth of plants. Steps in experimental design The first step involved developing the research questions and formulating the hypothesis. Next, the different aspects of the treatment conditions were distinguished and the Levels were then assigned to an independent variable based on simplicity. The subjects that represent the population which had been generated were then selected. After this, the sample frame was made, and the subjects for the experiments to the group were then assigned. Doing the test prior reveals that an error exists during the test. It is used to help carry out the refinement before final test and scripts can be revised here. Finally, the data needed for the experiment were analyzed using the relevant instrument the observational techniques. Reasons for using experimental research The experimental research will have better control of the irrelevant variables, unlike any other research design. The experimental research design manipulates the independent variable making it easy to determine the cause and effect relationship. The chosen research method will provide better results due to control set up by the experiment and strict conditions. Research question i. How does medium light intensity affect the growth of plants? ii. How does high light intensity affect the growth of plants? iii. How does the lack or the absence of light affect the growth of plants? My hypothesis is that plants exposed to a medium amount light will most likely grow faster than those that exposed to low and excess sunlight. It is because they use light to make food by the process called photosynthesis and need time to convert the glucose to starch at night. I based the current subject hypothesis on what I know concerning I already known about growth of plants, experiment and a book that has pictures of plants exposed to light and others covered by a shade. Dependent variable is the plant growth while independent variable is the light intensity. The level of exposure of light to the plant will determine growth rate. When the light intensity level that reaches the plant is small, the growth rate is also affected greatly. Regions that receive enough light experience fast plant growth. The controlling variables are temperature and humidity. Sequence of events to collect qualitative data Experiment trials Experimental observation, measurement and recording of the growth height under each level of exposure to light Materials The materials which were used to undertake the research include: i. 3 containers ii. 3 plant seedlings iii. 100 watt bulb iv. Dark room v. Plenty water Experimental Setup 2. The first procedure involved putting about 3cm3 of soil in each of the three containers 3. Next, the seedlings were planted in each container before adding equal amounts of water sufficient to support their growth 4. Using a 100 watts bulb as the light source, the first container was placed in areas exposed to 24 hours of light continuous, while the second container was placed in an area exposed to 12 hours light. However, the third container was placed and one in total darkness. 5. Finally, water was added on a daily basis and the growth of the plants was then monitored by measuring their heights each day. Results and Presentation The results of the experiment shopwed that the plants exposed to 12 hours grew the tallest, followed by the one exposed to the 24 hours light. On the other hand, the one in darkness didn’t grow at all as shown in the figure below: The above results particularly suggests that plants have optimum light requirements above or below which their growth may be hindered. For example, the plant exposed to excess light may not have grown well because excessive light intensity normally has adverse effects on the plant growth as it induces rapid transpiration leading to water loss. On the other hand, the third pant exposed to no light at all may have failed to grow due to a deficiency in the intensity of light required for photosynthesis which produces the energy and nutrients required for the plant growth. However, the plant exposed to 12 hours grew the tallest because the 12hours sunlight may have provided the optimum sunlight intensity required by the plant. Generally, light intensity is one of the most critical environmental factors influencing plant growth. The results clearly showed that plants in medium-light showed an enormous biomass of largest leaf area and longest stem length among all treatments. Low photosynthetic ability has frequently explained the low biomass of plants. The little photosynthesis can result in low growth rate. Excess photosynthesis causes photo damage. The plant in darkness did not grow because it needs light for growth meaning a plant will not grow in the dark. Conclusion and Evaluation The findings of the eexperiment confirmed my hypothesis that plants with medium exposure to light grow better than the ones on high and in the dark. Although different plants have different optimum light requirements, a deficiency in the intensity of light usually leads to impaired plant growth as the low levels of solar energy may restrict photosynthesis. On the other hand, excessive light intensity may also hinder plant growth due to adverse effects on the plant such as excessive heat growth that may lead to water loss, hence reduced growth. Replication Replicating the current experiment requires that all the requirements as well as the necessary conditions are put in place. This is particularly because plant growth that is being measured can also be affected by other factors thereby impacting on the validity of the results. For example, adding different water quantities may influence growth differences in the plants under study. As a result, it important to ensure that other factors and variables apart from the ones being measured are constant in all the three containers. Generally, replication of the experiment, particularly if a a larger population or different plant species are used may lead to more accurate and comprehensive results, which helps in better decision-making. Evaluation of Validity Experimental design is an essential factor in the success of scientific inquiry because it helps students well to understand the world and how to design their experiments. Consequently, any successful replication of this experiment would confirm its validity as this is likely to provide the much needed confidence that the initial findings were correct. This is particularly if the same results and findings are arrived at in the subsequent replications of the experiment. References D, E. (1999). Effect of acidic rain on plants growth. Education.com. Web Lederman, F. L. (2006). Scientific inquiry and nature of sciences. New York prentice-hall pub. Print Spilsbury, L. s. (2008). Plant Growth. Nj, Wiley and sons inc. Print Read More