Mitosis in Onion Root Tip (Allium Cepa)


Cell Biology and Genetics
  Cell Cycles
  Meiosis in Flower Buds of Allium Cepa-Acetocarmine Stain
  Meiosis in Grasshopper Testis (Poecilocerus Pictus)
  Mitosis in Onion Root Tip (Allium Cepa)
  Differential Staining of Blood
  Buccal Epithelial Smear and Barr Body
  Vital Staining of DNA and RNA in Paramecium
  Induction of Polyploidy
  Mounting of Genitalia in Drosophila Melanogaster
  Mounting of Genitalia in the Silk Moth Bombyx Mori
  Mounting of the Sex Comb in Drosophila Melanogaster
  Mounting of the Mouth Parts of the Mosquito
  Normal Human Karyotyping
  Black and White Film Development and Printing for Karyotype Analysis
  Study of Drumsticks in the Neutrophils of Females
  Study of the Malaria Parasite
  Vital Staining of DNA and RNA in Paramecium
  Sex-Linked Inheritance in Drosophila Melanogaster
  Preparation of Somatic Chromosomes from Rat Bone Marrow
  Chromosomal Aberrations
  Study of Phenocopy
  Study of Mendelian Traits
  Estimation of Number of Erythrocytes [RBC] in Human Blood
  Estimation of Number of Leucocytes (WBC) in Human Blood
  Culturing Techniques and Handling of Flies
  Life Cycle of the Mosquito (Culex Pipiens)
  Life Cycle of the Silkworm (Bombyx Mori)
  Vital Staining of Earthworm Ovary
  Culturing and Observation of Paramecium
  Culturing and Staining of E.coli (Gram’s Staining)
  Breeding Experiments in Drosophila Melanogaster
  Preparation of Salivary Gland Chromosomes
  Observation of Mutants in Drosophila Melanogaster
  ABO Blood Grouping and Rh Factor in Humans
  Determination of Blood Group and Rh Factor
  Demonstration of the Law of Independent Assortment
  Demonstration of Law of Segregation
  • Onion root tips
  • 1N HCl
  • Acetocarmine stain
  • Glycerine
  • Watch glass
  • Slides
  • cover slip
  1. Place 2–3 root tips on a watch glass.
  2. Add 2 drops of 1N HCl and gently warm it.
  3. Blot the HCl with blotting paper and then add 2–3 drops of acetocarmine
    stain and warm it.
  4. Allow the root tips in stain for 5–10 minutes.
  5. Take the stained root tips on a slide with 2–3 drops of glycerine.
  6. Place the coverslip over the slide with a blotting paper and squash it with
    a thumb
Mitosis is also called somatic cell division or equatorial division. The process of cell division, whereby chromosomes are duplicated and distributed equally to the daughter cells, is called mitosis. It helps to maintain the constant chromosome number in all cells of the body.


Interphase is also called the resting stage. This is a transitional phase between the successive mitotic divisions.
  1. Replication of DNA takes place.
  2. The volume of the nucleus increases.
  3. The chromosomes are thinly coiled.
  1. Each chromosome consists of chromatids united by a centromere.
  2. Spindle formation is initiated.
  3. The chromosomes shorten, thicken, and become stainable.
  4. The nuclear membrane and nucleolus start disappearing.
  1. Disappearance of the nucleolus and nuclear membrane.
  2. Chromosomes are at their maximum condensed state.
  3. Spindle formation is complete.
  4. The chromosomes align in the equatorial position of the spindle and form the equatorial plate that is at a right angle to the spindle axis.
  5. The centromeres are arranged exactly at the equatorial plate and the arms are directed toward the poles.
  1. The centromere of the chromosomes divides and the 2 chromatids of each pair separate.
  2. Sister chromatids start moving toward the opposite poles due to the contraction of chromosomal fibers.
  3. The daughter chromosomes assume “V” or “J” shapes.

  1. It is the reverse of prophase.
  2. The chromosomes aggregate at the poles.
  3. The spindle starts disappearing.
  4. The new nuclear membrane starts to reappear around each set of chromosomes.
  5. The nucleolus gets reorganized.

A cell plate is formed by the formation of phragnoplast from the Golgi complex. Later the primary and secondary wall layers are deposited. Finally, the cells are divided into 2 daughter cells. The cytoplasm gets divided into 2 parts.