The correct sequence for plant cell mitosis is prophase, prometaphase, metaphase, anaphase, and telophase, followed by cytokinesis. Plant cells also have a unique preparatory step called preprophase that occurs before mitosis officially begins. While this sequence mirrors animal cell division in broad strokes, plant cells handle several key steps differently because they lack certain structures that animal cells rely on.
Preprophase: Setting the Division Plane
Before mitosis starts, plant cells go through a step that animal cells skip entirely. During late G2 phase (the gap period just before mitosis), a broad band of protein filaments called the preprophase band forms around the cell’s midsection, like a belt. This band marks exactly where the cell will eventually split in two. It starts wide and gradually narrows during prophase, shrinking to roughly 7 micrometers across as it defines a precise cortical division zone.
This matters because plant cells are locked inside rigid cell walls and can’t simply pinch inward to divide the way animal cells do. The preprophase band essentially draws a line on the inside of the cell that later structures will follow when building the new wall between daughter cells. By the time mitosis is fully underway, the band itself disappears, but the positional information it left behind persists.
Prophase: Chromosomes Condense, Spindle Begins
Prophase is the longest stage of mitosis in plant cells. In pea root cells, prophase lasts about 2 hours, compared to roughly 25 minutes for metaphase and just 5 minutes for anaphase. During this stage, the loosely organized DNA in the nucleus coils tightly into visible chromosomes. Each chromosome consists of two identical copies (sister chromatids) joined at a central point.
Here’s where plant cells diverge from animal cells in an important way. Animal cells use structures called centrioles to organize the spindle fibers that will pull chromosomes apart. Plant cells don’t have centrioles. Instead, they nucleate spindle fibers directly on the surface of the nuclear envelope, then organize those fibers into two opposing poles. This process produces what’s sometimes called a prophase spindle, and it works just as effectively despite the missing hardware.
Prometaphase: The Nuclear Envelope Breaks Down
Prometaphase begins when the membrane surrounding the nucleus fragments and dissolves, releasing the condensed chromosomes into the cell’s interior. Spindle fibers, which have been assembling outside the nucleus, now reach in and attach to specialized protein structures on each chromosome called kinetochores. Each sister chromatid has its own kinetochore, and fibers from opposite poles of the spindle compete to attach to opposite sides of the same chromosome pair. This tug-of-war is what will eventually line the chromosomes up in the middle of the cell.
Metaphase: Chromosomes Align at the Center
During metaphase, all chromosomes are lined up along the cell’s equator, forming what’s called the metaphase plate. Each chromosome is attached to spindle fibers from both poles, with one sister chromatid connected to one pole and the other to the opposite pole. The cell essentially pauses here while a built-in checkpoint confirms that every chromosome is properly attached. If even one chromosome isn’t correctly connected to both poles, the cell delays moving forward. This prevents daughter cells from ending up with the wrong number of chromosomes.
Anaphase: Chromosomes Separate
Anaphase is the fastest stage. The protein glue holding sister chromatids together dissolves, and the two halves of each chromosome are pulled toward opposite poles. This happens through two overlapping mechanisms. In anaphase A, the spindle fibers attached to each chromatid shorten, reeling the chromatids toward the poles. In anaphase B, the spindle itself elongates, pushing the two poles further apart and increasing the distance between the separating chromosome sets. In some organisms these two steps happen one after the other, but they can also occur simultaneously.
By the end of anaphase, two complete and identical sets of chromosomes sit at opposite ends of the cell.
Telophase: Nuclei Re-form
During telophase, the process essentially runs prophase in reverse. Nuclear envelopes reassemble around each set of chromosomes, the chromosomes begin to uncoil back into their loosely organized form, and structures inside the nucleus (like the nucleolus) reappear. At this point, the cell has two distinct nuclei but is still one cell.
This is also when the phragmoplast begins to take shape. The phragmoplast is a structure unique to plant cells, made of protein filaments, membrane compartments, and associated proteins. It forms between the two new nuclei during the transition from anaphase to telophase, initially appearing as a small disk roughly the same diameter as the daughter nuclei. Its job is to guide construction of the new cell wall.
Cytokinesis: Building the New Cell Wall
Cytokinesis in plant cells looks completely different from animal cells. Animal cells divide by pinching inward with a contractile ring, like tightening a drawstring. Plant cells can’t do this because of their rigid cell walls. Instead, they build a brand-new wall from the inside out.
The phragmoplast directs tiny vesicles (membrane-wrapped packages of building materials) to the center of the cell, where they fuse together. This fusion process passes through four distinct membrane stages. First, arriving vesicles merge into dumbbell-shaped structures. These then reshape into a tubular-vesicular network as specialized proteins cause the membranes to form tubes. Next, the cell deposits callose (a stiffening sugar) into this growing structure, creating a more solid network. Finally, cellulose and other structural sugars are added to rigidify the new wall.
As the cell plate matures in the center, the phragmoplast expands outward like a growing ring. Protein filaments break down behind the expanding edge (where the plate is already mature) and new filaments assemble at the leading edge (where construction is still happening). In some elongated cells, like those in woody tissue, the phragmoplast may need to expand up to 100 times its original diameter to reach the edges of the parent cell. Once the cell plate connects to the existing cell wall and plasma membrane on all sides, cytokinesis is complete, and two separate daughter cells exist.
How Long the Whole Process Takes
The entire mitotic phase is surprisingly brief compared to the rest of the cell cycle. In the model plant Arabidopsis, mitosis lasts only about 20 to 25 minutes, representing just 3 to 4 percent of total cell cycle time. The bulk of the cycle is spent in interphase, particularly the G2 phase, which ranges from 3.5 hours in some cell types to over 4.5 hours in others. The total time from DNA replication through the end of mitosis runs about 4 to 5.5 hours depending on cell type and position within the root.
Pea root cells, which are larger, take considerably longer. Their interphase lasts about 23 hours, with prophase alone accounting for 2 hours. Metaphase takes around 25 minutes, anaphase about 5 minutes, and telophase roughly 22 minutes. The dramatic difference between species reflects how cell size, genome size, and growth conditions all influence division speed.
Key Differences From Animal Cell Mitosis
- No centrioles. Plant cells assemble their spindle using protein filaments nucleated on the nuclear envelope rather than organizing them from centriole-containing centrosomes.
- Preprophase band. This structure, which marks the future division site, has no equivalent in animal cells.
- No contractile ring. Instead of pinching in half, plant cells build a cell plate from the center outward using the phragmoplast.
- Cell wall construction. The final product of plant cytokinesis is a new cell wall complete with structural sugars like callose and cellulose, not just a membrane boundary.