Factors Affecting the Rooting of Stem Cuttings

Factors Affecting the Rooting of Stem Cuttings

Research Question

To determine how the number of leaves left on a 15 cm Aluminium Plant (Pilea cadierei) stem cuttings affects the number and length of roots when placed in a Nestle Pure Life water bottle filled with 100 mL of tap water for 30 days by a glass pane window.

Background Information

Asexual reproduction is a type of reproduction in which offspring(s) arise from a single parent. More specifically, asexual cellular reproduction occurs in all types of living organisms. It may be for growth, embryonic development, tissue repair and regeneration or to increase surface area to volume ratio in order to gain cellular efficiency. Since asexual reproduction produces offspring from just a single parent, the genetic makeup of the offspring will be in essence, copies from that of the parent. The reasoning behind the identical genes are attributed to mitosis, interphase, and cytokinesis. Before mitosis occurs, there is a long period known as interphase in which the cell grows and the DNA self-replicates within the cell. Once the DNA has replicated, mitosis occurs in four stages (prophase, metaphase, anaphase and telophase) which with cytokinesis, helps the cell divide into two different masses, both with the same DNA.

Clones, like cells in mitosis, are organisms that are genetically identical to its parent. Cloning can occur both naturally and within artificial settings. Focusing on plants, they are able to clone parts of themselves asexually through mitosis. Stem cuttings are a method of cloning that relies on the meristem to develop its undifferentiated cells into roots in order for the processes of life to continue. Stem cuttings are also a very cost efficient method for common gardeners and botanists to grow plants that could be more expensive to purchase commercially.

An Aluminium Plant is suitable for cloning for a variety of reasons. One big reason being, the large leaves on the plant help further the independent variable that will be manipulated throughout the duration of the experiment. Generally, the larger the leaf, the larger the surface area the leaf obtains as well. With the larger surface area, process such as photosynthesis is able to be carried out more effectively which affects the cloning and growth of the plant. The Aluminium Plant is easily cultivated, fast growing, easy to maintain and affordable. This makes it an interesting plant to clone because many profits can be made from generating more quantity from a common popular house plant.

4A. Independent Variable

The independent variable that we will be changing/ manipulating for the purpose of this lab will be the number of leaves left on the stem cutting. The units of measure for the number of leaves will be each. The simulations for the independent variables will be 0 leaves, 1 leaf, 2 leaves, 3 leaves and 4 leaves while all other variables affecting the rooting of stem cuttings remain constant. The stem cuttings for the purpose of this lab are generally fairly small. As a result, for what is essentially a smaller plant, there are normally a smaller number of leaves as well. It is believed that there is a relationship associated with the number of leaves left on the stem cutting with the potentiality of the growth of roots on stem cuttings. This belief is fueled by the idea that leaves harvest energy and produce food for the plant through process such as photosynthesis that of which affect the growth of not only the roots and cloning, but the whole plant as well.. Since the stem cutting is not only small, but does not have any roots yet, water and nutrients are limited for the whole plant, including the leaves. Moreover, we will be able to measure the number of leaves simply by counting or just numbering.

4B.Dependent Variable

The dependant variable that we will be measuring after having completed the experiment is the number of roots that the stem cuttings have generated and the length of the roots in centimeters. We will measure the number of roots by the means of counting them out and utilise a ruler in order to accurately measure the length. This would therefore mean that the unit of measurement would be for example 1 root, 2 roots, 3 roots, 4 roots, 5 roots and so on while the unit of measurement for the length of the roots will be varying in centimeters. These units of measurement will remain the same as the independent variable changes. We will obtain our measurements of the number of roots on each sample by counting out the roots and by measuring the length of each root using a ruler. After collecting the data we assume that both the root size and number of roots present on the sample are equally important. However, we will consider the greatest possible number of roots and the greatest length of the root on a sample to represent the number of leaves that best fits the other constant factors throughout the experiment.

4C. Fixed/Controlled Variable

Fixed/Controlled Variables

How will it be controlled?

Type and age of plant (days)

Assure that all stems are taken from the same batch of plants, assuming that they were harvested at the same time.

Sizes of the stem cutting (cm)

Each stem will be measured and cut at the same length to assure accurate results.

Number of holes in sandwich bags (numbering)

Cutting each sandwich bag exactly the same, therefore the bag over each plant will have the same amount of holes.

Type and amount of water (mL)

Measuring the amount of water used each time (tap water).

Amount of light exposure (hours per day)

Placing all plants in an area (window) where light may be distributed equally.

Temperature of plant (°C)

Place