Mitosis in Plants:
Mitosis is the term for a cell-division process where a diploid (2n) parent cell splits into two
diploid daughter cells that are genetically identical. The process is necessary for growth, healing
of tissues, and asexual reproduction in plants.
Features of Mitosis in Plants
Occurs in somatic (non-reproductive) cells (e.g., root tips, shoot tips)
Maintains chromosome number (2n → 2n).
No genetic variation (daughter cells are clones).
Used for:
1. Primary & secondary growth (via apical & lateral meristems).
2. Asexual reproduction (e.g., runners, tubers).
Stages of Mitosis
A. Interphase (Preparation for Division)
G1 Phase: Cell grows, organelles replicate.
S Phase: DNA replication (chromosomes duplicate).
G2 Phase: Final preparations (check for DNA errors).
B. M Phase (Mitosis Proper)
Stage Key Events in Plant Cells Prophase
Chromatin condenses into visible chromosomes (each with 2 sister chromatids).
Nucleolus disappears, nuclear envelope breaks down.
Plant cells lack centrioles, but spindle fibers still form from microtubules.
| Metaphase |
Chromosomes align at the metaphase plate (equator).
Kinetochore microtubules attach to sister chromatids.
, | Anaphase |
Sister chromatids separate, pulled to opposite poles.
Now called daughter chromosomes.
In plant cells:
Cell plate forms from vesicles of Golgi at the equator. Develops into a new cell wall, separating
daughter cells. Cell plate forms from Golgi vesicles at the equator. Develops into a new cell wall,
separating daughter cells. Cell plate forms from vesicles of Golgi at the equator.
Unique Aspects of Mitosis in Plants
No centrioles: Spindle is made from microtubules going to MTOCs (the place where
microtubules are generated).
Cell plate formation: Cell wall being rigid, plants cannot do the process of cytokinesis
like animals.
Occurs in meristems: Apical meristems → primary growth. Vascular cambium →
secondary growth.4. Role in Plant Growth & Development
Root & Shoot Growth: Mitosis in apical meristems increases length.
Secondary Growth: Vascular cambium mitosis produces wood (xylem) and phloem.
Asexual Reproduction: Stolons/runners (e.g., strawberries