The two most important processes of dividing cell are mitosis and meiosis. Both mitosis and meiosis are associated with generating a new cell.
The onion root tip is often named as one of the most important and proper root specimens. The presence of a meristematic cell is integrally associated with the specification of the mitosis procedure. Overall changes in chromosomes can be measured properly by analyzing a proper mitosis procedure.
Each of the available living organisms is found to possess a basic unit that is known as a cell. Each cell is found to be divided into parts at a certain age of its lifetime. In this action, the process of mitosis takes place.
The examination of mitosis in the root cell of an onion presents that in mitosis, a parent cell is divided into two daughter cells. Thus in this process, it is observed that the eukaryotic cell’s nucleus was divided into two significant parts and therefore the whole cell is divided into two parts.
Figure 1: Mitotic cell division process
In maintaining a regular life process, mitosis in a cell is very necessary. Some of its surrounding environmental factors such as time and temperature impact the mitosis procedure.
A whole mitosis process is divided into four main phases: prophase, metaphase, anaphase, and telophase. There are some other phases as well in between these stages where some important actions of mitosis take place.
Figure 2: Different phases of mitosis
Prophase − In this stage, the chromosomes are found to start coiling.
Metaphase The chromosomes are found to start thickening and are placed at the midline of a cell.
Anaphase − Each of the chromatid pair separates from the cell’s centromere and is found to move at the opposite ends in this stage.
Telophase − Each of the daughter cells is uncoiled at this stage and generates chromatin fibres.
Figure 3: Presentation of metaphase
The main aim of this study is to understand all relevant information regarding mitosis by preparing an onion root’s temporary mount.
In executing this process of mitosis in an onion root, some specific materials are needed.
Dry roots of an onion
A sharp blade
Vials
Forceps
Microscopes
Cover slips and glass slide
Beaker
Hydrochloric acid
Water
Acetocarmine stain
Aceto-alcohol mixture
Filter paper
In observing the mitosis process, a single slice of onion is to be placed on the tile. A dried root tip is to be removed with a sharp blade. In growing root tips, the bulb is to be placed in the beaker that is filled with water.
In sprouting a new root, 3 to 6 days are required. This newly grown root is to be taken and cut off for understanding the mitosis procedure. The prepared aceto-alcohol is to be used and the cut-off new roots are placed in this solution. In this fixative, the root tips are soaked for nearly a whole day.
A single amount of root is to be taken and placed on a clear glass slide. A dropper is to be used to drop only a single drop of N/10 HCl and after those, 2 to 3 drops of acetocarmine stain is to be used. In a stove, this is to be heated for a while. Any amount of excessive strain is to be soaked by using filter paper.
A perfectly stained tip is to be taken and placed on the slide and then under the microscope. Just before following the stages, a single drop of water is to be placed on that collected root tip and a cover slip is also to be attached with a needle.
The cover slip is to be tapped in such a manner so that the root tip’s meristematic tissue is fully compressed. This action leads to spreading out the tissue as a thin layer and the preparation is ready to be studied each stage of mitosis.
Each stage of a whole mitosis procedure can be easily observed. The parent cell is divided into two different parts and produces two daughter cells in each of which, nuclei are present.
The mitosis procedure is essential for a living being as the generation of new cells is integrally connected to the mitosis process. Dead cells are eliminated as well with the help of this process. Each of the required materials for this experiment plays a significant individual role in observing the overall procedure of a mitosis process. Understanding the process can help an individual in studying each and every step of mitosis and analyzing the changes, undertaken in chromosomes.
Q1. What is the process of strewn mount?
Ans. In a strewn mount process, a palynological microscope is prepared with the help of a concentrated sample. All the collected samples are placed on a particular slide and the placed water is allowed to evaporate accordingly.
Q2. What is the necessity of using HCI in treating an onion root cell?
Ans. HCI is considered a very strong acid and therefore capable of hydrolyzing the available onion cells. The middle lamella within any particular onion cell can be easily studied and the changes in chromosomes are also well-followed by using this acid.
Q3. Which other cells can be helpful in studying mitosis?
Ans. Rather than onion cells, some other cells are also capable of presenting all stages of mitosis and changes in chromosomes clearly. Some of these are the tail of tadpole larvae, a grasshopper larva, bone marrow tissue of a vertebrate, and many more.
Q4. What is the significance of an onion cell in studying mitosis?
Ans. In studying mitosis, meristematic cells are the most capable and significant ones. The chromosomes of a monocotyledonous plant are very apparent and large in size. Therefore, an onion root cell is the most appropriate and significant object in studying the stages and processes of mitosis.