Dry Mass Change During Germination of Bean Seeds | Free Essay Example

Dry Mass Change During Germination of Bean Seeds

Words: 2484
Topic: Sciences
Updated:

Project Plan/Problem Statement

This paper is an assessment concern with a dry mass of seeds. The assessment will deal with various ways of performing adaptable procedures of evaluating and monitoring changes in the dry mass of bean seeds during germination. It is an examination relating to germination through analysis of the seed’s dry mass during germination. The experiment is done to find out the relationship between the mass of a seed (organic matter in seed) and the germination. When seeds are left to germinate, are there notable changes in the mass? Does this change indicate that dry mass increases as the seed continue to germinate? Do the results, therefore, indicate that a possible conclusion is that the dry mass of a seed determines the development of a seed?

Literature Review

Dormancy and Germination of seeds

The ripe seeds of a plant germinate only when they are exposed to some favorable climatic conditions, such as warmth. Most seeds cannot germinate immediately after they are shed (Hoh, 2002). They undergo a resting period known as the dormant stage through which they cannot germinate even when the conditions are favorable. The dormant period depends on species and thus vary from days, weeks, or months. The dried seed has a low metabolism, and their respiration is anaerobic, therefore they withstand harsh climatic conditions such as extreme colds or dryness (Hoh, 2002). Dry seeds, therefore, have a prolonged dormant period and only sprout when the conditions become favorable.

The growth of an organism involves additional substances besides the seed’s body content (Filson, 2005). The uptake means that the organism gets larger but the definition of growth excludes the temporary changes such as the results of water intake through osmosis. Plants growth occurs at particular parts, but the growth can be measured in several ways, for instance, the increase of size, mass, volume, or the number of cells. The growth of plants can thus be measured through analysis of their heights, but a better way is to measure the changes in dry mass. Dry mass is the number of organic materials in an organism without considering the water content in its cytoplasm.

Experimental Design Steps

Requirement

  1. Approximately 100 broad bean seeds;
  2. Oven;
  3. Electronic Beam Balance;
  4. Soaking basin;
  5. Germination pot.

Experimental Procedure

  1. The first step involves the soaking of the experiment sample seeds, approximately 100 broad bean seeds for a day (24hrs).
  2. The researcher must use enough water for the seeds (approximately 1 liter of water) for soaking.
  3. The researcher should then pick a few (Approximately 10) of the soaked beans and dry in the oven at approximately 80oC heat.
  4. The beans that are subjected to drying are then measures on a beam balance or other alternative measuring tools (preferably electronic measures, for better accuracy).
  5. The heating has to continue at 80oC until a constant mass is reached.
  6. The heating process assists in drying the moisture content until the remaining mass (dry mass) is only made of plant food matter.
  7. The measuring ought to continue until a constant mass of most of the 10 picked samples is reached.
  8. The researcher records the mass of the dried beans as dry mass in a data-collection table.
  9. The rest of the seeds are allowed to germinate, but the same number of seedlings are selected at random every two days, and their dry mass obtained as indicated in steps two to seven.

The traditional procedure of measuring dry mass

In cases where some of the requirements, such as oven-drying requirements are not available, the researcher may decide on using the sunlight and store the seed in a dry place free from moisture for a few days. The researcher then keeps measuring the mass of the seeds until one day or consecutive days when they have the same mass (dry mass). Any other measuring equipment that is not electronic may be used but has to enforce accuracy.

Reasoning

This method of collecting data concerning the dry mass of seeds is the most common quantitative way for the experiment. The accuracy is achievable through the use of perfect measuring tools and consideration of a wide range of sample data (bean seeds). The recording table assists to stipulate the results clearly and accurately. It is a precise means of collecting and comparing information for analysis. To limit possible errors, the researcher may monitor activities over a longer period, for instance, over a couple of consecutive days or weeks, otherwise, accuracy can be ensured by repeating the exercise several times.

The seeds are allowed to continue germinating while the researcher measures the dry mass after every two days. The procedure of measuring the dry mass of these germinating seeds enables the researcher to find out if there is a difference in the number of organic materials in germinating seeds. Does the amount of organic material in the seed relate to germination/growth rate?

The Sequence of Events

The collection of quantitative data involves appraisal and recording of measured data in a table as obtained during different periods.

The results are as indicated in the table below:

Day 0 2 4 6 8 10 12
Dry Mass (g) 8 6 5 5 7 11 15

Note: Day “0” marks the commencement of the experiment

The results are thus represented in a graph as shown below:

Change of Dry Mass during germination

The plotting involves the dry mass (in grams) along the vertical axis against the time (days) along the horizontal axis.

Tools

One of the data collection tools will be an analysis of the available information. It is an inexpensive and fast way of examining trends and researched information because it only involves the literature review. The experiment will mainly involve measuring of dry masses during different days of the experiment. The analysis of the relationship between the days and dry mass index will assist in making a conclusive report regarding the germination of seeds.

Variables

Variables are changing entities of an experiment. The first types are the independent variables. A scientist can make changes to these variables to observe the effects. Secondly, there are some dependent variables in an experiment, in which case the variables respond to the changes made on the independent variables. The value of a dependent variable, therefore, depends on that of the independent variable. Lastly, the controlled variables are those quantities of an experiment that the scientist would prefer if they remain constant during the experiment.

Independent Variable: these will be the quantity controlled by the researcher. In this study, the dependent variables will be the intervals of days the germinating seeds are collected for the experiment.

Dependent Variable: These will be the measured results of the experiment; the Dry Mass.

Controlled Variables:

  1. Moisture.
  2. Type of the seed.
  3. Quality of the seeds (seed should not be infected or have holes).
  4. Duration and intervals during the collection of mass reading and recording.
  5. Environmental conditions (Moisture/Rainfall/Warmth) – all seeds to use in this experiment must be dried at approximately 80oC.

The main objectives of any experiment are to have an equalized set of variables from transformed data, normalize the observation, and select appropriate regression variables. The main aim of focusing on the right transformation procedure is to ensure the use of correct statistical courses of actions such as computations. The coding of data will involve ranking from original observation and common standardization for simplified arithmetic in addition to computation. Unlike in data transformation, coding involves variables, which are more important and interesting for the researcher, for instance, the dry mass.

Threat Reduction to Internal Validity

  1. The process of finding the dry mass of seeds may cause harm to organisms or even kill them; therefore, one cannot use this experiment to determine the growth of one organism or seed. It is the reason why a sample of 100 seeds is preferred, and a random section is picked from this sample at different points in time to dry and determine the dry mass. A certain number of seeds (a random sample of ten seeds) need to be taken from the large quantity of 100 to determine their mean mass otherwise, the procedure may not be accurate when very few seedlings are involved.
  2. Constant environmental conditions must be maintained to avoid interference of the dry mass, such as the moisture content in the seeds.
  3. The duration and interval between consecutive measures must be accurately equal to avoid ambiguity and lack of consistency.
  4. The procedures may also not be 100% accurate the first time. It means that the experiment and plotting of mean mass results need to be carried out over time to tell about the average growth of the plant being studied.
  5. The seeds are mainly in a dominant stage, and spotting the physical changes without the qualitative measure is difficult.
  6. The experiment method of determining growth may have relative benefits or disadvantages, depending on the environmental situation.
  7. The dry weight may have little change or remain constant for a long time during the experiment period, depending on the climatic conditions, type, and nature of the seeds.

Hypothesis

The hypothesis is that the dry mass of germinating bean seeds has a direct relation to the quantity of seeding development/plant growth. An increase in dry mass of the seed increases as the seed germinates or seedling develops.

Considering various research findings (Hoh, 2002), the weight of seeds have very big effects on germination. The seed with greater dry mass has a faster germination rate and better seedling formation than seeds with small and medium mass. On measuring the dry mass of germinating seeds, the seeds with higher mass will have greater (Hypothesized better) growth than seeds with low dry mass.

Process of Data Collection

The dry mass is achieved by drying ten seeds in an oven at 80oC. The measure has to occur through consecutive measures until a constant quantity is achieved. The procedure evaporates the water in the cells but does not destroy the carbohydrates, proteins, and lipids.

The researcher should allow the sampled seeds to continue germinating, but a section made of ten seeds is picked after every two days for drying and successively measure of the dry mass recorded against the germination days, as indicated in the procedure and table. The process that causes the changes in dry mass during the first six days of germination is differentiation, in which case the cells divide and become specialized for particular functions.

Appropriate Methods

The mentioned data collection strategy in the experiment is more appropriate because it assists in the implementation of the sampling and collection of routine observational data. The data collection procedure involves valid measurement of dry mass and is thus more appropriate as opposed to the qualitative methods. This numerical inference, therefore, minimizes or reduces approximation errors. The data seed samples shall be random and of the same type. The time difference is also kept constant for accuracy and consistency. The units of measurements are also appropriate since they represent the exact quantity (grams for the dry mass).

Results

Possible explanations for recorded dry masses

The experiment is a quantitative procedure of measuring and recording dry masses of germinating seeds. There is an approximate decline of 50% of the dry mass for the germinating seeds, however, the increase of mass after a couple of days during the experiment indicates that the germination cells absorb nutrients released from the non-germinating cells of the seeds. The lipid bodies of the seed constitute the highest percentage of the mass, but it decreases as the seed starts undergoing the germination procedure.

In measuring the growth of plant cells during germination, the developing young plant uses stored up organic food for the development of fresh tissues and respiration. The sudden and rapid initial decrease of dry masses (for the first four days) is, therefore, due to a speedy increase in the growth of cells for the development of root and shoot. The initial stages of germination are thus rapid because water and air intake mobilize the use of the reserved endogenous nutrients for the induction of the seed development phase. The speedy intake of water, therefore, initially affects the dry weight indirectly, but eventually stabilizes.

The dry mass increases steadily similar to an increase in the number of days the seeds are left to germinate since there is a decrease in the transfer of materials from endosperm or cotyledon. There is a steady increase of dry mass, the more the days that these seeds are left to germinate. The initial metabolic change precedes cell division, but there is a cellular expansion that overcomes the cell division.

Conclusion

There are chemical changes of various components such as sugar, fat, nitrogen, and nucleic acid in the embryo of the seed that causes a decrease of the dry mass. There are, therefore, many changes occurring during the initial stage that is associable with the recommencement of growth. The initial process of germination is therefore largely related to reserves on the endosperm that suffers a huge loss of proteins and other insoluble carbohydrates. An initial couple of days during the experiment also cause devastating changes in sugar content, thus affecting the dry mass.

The content of fat in the endosperm of the seed is drastically affected due to the concurrent increase of soluble nitrogenous elements and carbohydrates.

Confirmation of Hypothesis

The results of the experiment confirm the hypothesis that the dry mass of a bean seed has a direct relation to the quantity of plant growth because the more the seeds are left to germinate, the higher the amount of measured dry mass.

Experimental Design as Key Factor

The experimental design assists in the planning of research, especially when the study concerns the natural entities and deliberate exploitation of definite variables. The procedure assists in taking observations and measurements to help in determining the effects of conditional changes in an experiment. Poor experimental designs cause misunderstanding of the idea or processes of manipulating variables (the days that the seeds are allowed to germinate before testing).

Replication

The measure of the dry mass of a seed involves several seeds to enhance reliability. Before acceptance and establishment and final documentation of these findings, different researchers must repeat research preferably, as a self-correction measure. A researcher must, therefore, spell out the exact procedure of measuring attributes, operational definitions, and measurement performances, as indicated in the experimental procedure.

Evaluation of Validity

The experiment shall not utilize a huge period for data collection and analysis but focuses on a couple of day’s analysis (twelve days), which is a better representation of the subject under the study. It enables the researcher to avoid faulty experiments, wrongly calculated/measured data, and poor sampling techniques. There will be a need to assume the possibility of faulty data for better screening procedures as a way of avoiding errors, for instance, the need to re-check data recollection and re-examination of data. It may also call for further research studies or additional computation of data to ensure consistency, especially in the measuring units.

References

Filson, G. (2005). Intensive Agriculture and Sustainability: A Farming Systems Analysis. Canada: UBC Press.

Hoh, Y. (2002). Longman A-Level biology: growth, development and reproduction. Singapore: Pearson Education South Asia Publishers.