Cannabis Plant Cells: How They Work and What Growers Can See

By Rick Smith / February 27, 2021

Extreme macro of clear and milky glandular trichomes on a cannabis flower

Table of Contents

Quick answer: Cannabis plant cells are built like other plant cells. Each one has a cellulose cell wall, a cell membrane, a nucleus that holds the genetic information, mitochondria for respiration, chloroplasts for capturing light and a large central vacuole full of water. When the vacuoles are full, the plant stands firm. When they lose water, it wilts. New growth comes from small zones of dividing cells at the shoot and root tips.

What Is Inside a Cannabis Plant Cell?

Every cannabis plant is made of millions of tiny cells. Most of what you see in the garden, from a firm stem to a drooping leaf, starts with what happens inside them.

Virginia Cooperative Extension describes the basic plan clearly. “Plant cells consist of a cell wall containing cellulose.” Inside that wall, a plant cell has some of the same parts as an animal cell, including a cell membrane, mitochondria, a nucleus and one or more vacuoles. Plant cells also have chloroplasts, which animal cells lack.

The UC Berkeley Museum of Paleontology adds that plant cells have three features that set them apart: “a cell wall, large central vacuole, and plasmodesmata.” Plasmodesmata are tiny channels that connect neighboring cells across their walls, so cells can share materials.

Cell part	What it does
Cell wall	A rigid layer of cellulose that holds the cell’s shape
Cell membrane	A thin layer inside the wall that controls what moves in and out
Nucleus	Holds the cell’s genetic information
Mitochondria	Carry out respiration, the cell’s energy release
Chloroplasts	Capture light and hold the green and orange pigments
Central vacuole	A large bag of water, nutrients and wastes that keeps the cell firm
Plasmodesmata	Channels that link one cell to the next

The Cell Wall and Membrane

The cell wall is the outer frame of the cell. Because it is made of cellulose, it is strong but still lets water through. It stops the cell from bursting when it fills with water, and it gives the whole plant its structure when millions of walls press against each other.

Just inside the wall sits the cell membrane. It is thin and flexible, and it controls which substances enter and leave the cell. The two layers work closely together. The membrane manages traffic, and the wall holds the shape.

Chloroplasts and Mitochondria

Chloroplasts are the reason cannabis leaves are green. Virginia Cooperative Extension explains that “Chloroplasts are the sites of photosynthesis and contain chlorophylls and carotenoid pigments.” Chlorophyll gives the green color, while carotenoids are yellow and orange pigments that are usually masked by the green.

Most chloroplasts sit in the leaf. Nebraska Extension describes two layers of leaf cells packed with them, the palisade mesophyll near the top surface and the spongy mesophyll below it. Our guide to how photosynthesis drives cannabis growth covers the full process.

Mitochondria are found in nearly every cell, including root cells that never see light. Virginia Cooperative Extension describes them as “responsible for respiration, or energy production.” They release the energy stored in sugars so the cell can do its work.

The Nucleus

The nucleus is the cell’s control center. Virginia Cooperative Extension notes that it contains the genetic information. Each cell carries the same set of instructions, and different cells use different parts of them. A leaf cell and a root cell share the same instructions but do very different jobs.

The Vacuole and Turgor: Why Plants Stand Up or Droop

The large central vacuole is the part of a plant cell growers see most clearly, even if they never think about it. UC Berkeley describes it as “a membrane-bound bag of fluid, containing ions, stored nutrients, and waste materials.” Plants cannot get rid of wastes the way animals do, so the vacuole stores them.

The vacuole also keeps the cell firm. Water moves into the vacuole and the cell swells until it presses against its wall. This outward push is called turgor pressure. Nebraska Extension puts it simply: “Cell turgor is driven by large water-filled vacuole.” When all the cells hold this pressure, the plant stands upright.

When the cells lose water, the pressure drops and leaves droop. UC Berkeley compares this with crisp fresh celery and celery that has gone limp after sitting out. The limp stalk has lost fluid, so it is no longer rigid. A wilting cannabis leaf is the same story on a larger scale.

Nebraska Extension adds that cell expansion, a driving force of growth, is also driven by water pressure inside the cells. The tiny guard cells around each leaf pore open and close the same way, by changes in turgor.

Meristems: Where New Cells Are Made

Cannabis grows taller and wider because cells divide and then expand. Virginia Cooperative Extension explains that “The apical meristem of the root/shoot is the site of cell division that makes the plant elongate.” The shoot tip and each root tip carry a small zone of fast dividing cells.

Behind each root tip is a zone of elongation, where new cells take up water and get longer, pushing the tip forward. That is why damage to growing tips can slow a plant down for a while.

Plant cells can also be grown in a lab as cell cultures, separate from a whole plant, which is a research method rather than a home growing technique.

Secretory Cells in Trichomes

The frosty coating on cannabis flowers comes from trichomes, tiny structures on the plant’s surface. Utah State University Extension notes that CBD is produced in trichomes, which occur in the highest density on unpollinated female flowers. University of Florida IFAS Extension adds that most of the cannabinoids in the plant are found in the secretory cells in the glandular trichomes on flowers and nearby leaves.

Those secretory cells are specialized cells whose job is to make and release resin rather than to capture light. Our guide on trichome production before harvest covers what growers watch for late in flower.

How to Read Cell Level Signs on Your Plants

You cannot see a single cell without a microscope, but you can see what millions of cells are doing. Use these steps on a regular walk through your garden.

Check firmness in the morning. Leaves should be firm and held out from the stem. Drooping early in the day means the cells are short on water pressure.
Compare with the afternoon. Some droop in heat can recover by evening. Droop that stays into the next morning needs a closer look.
Look at the growing tips. New leaves at the top should keep appearing. If the tips stall, something is slowing cell division and expansion.
Check leaf color. Even green color means chloroplasts are packed with chlorophyll. Pale or yellow new growth is worth a closer look.
Check the root zone. Lift the pot or check the soil to see whether the roots have water and air.
Change one thing at a time. Adjust water, light or feeding one step at a time so you can see what made the difference.

Troubleshooting

Plants wilt even though the soil is wet. The cells need water, but the roots may not be taking it up. Waterlogged roots short on air are a common cause. Our guide to the importance of cannabis roots explains what roots need.

New growth is pale. Chloroplasts in new leaves are not filling with chlorophyll. Check light, feeding and the root zone before you change anything else.

Tips grow slowly after a transplant. The meristems are working with fewer root tips while the plant settles. Give it time, steady water and stable conditions.

Leaves look crisp at the edges. Cells at the leaf edges dried out. Our guide to cannabis leaf anatomy explains how the leaf is built.

Plants droop every afternoon but recover overnight. The cells lose water faster than the roots supply it in the heat of the day. Check that the pot is not drying out and that the room is not too hot.

Frequently Asked Questions

What are the main parts of a cannabis plant cell?

A cannabis plant cell has a cellulose cell wall, a cell membrane, a nucleus, mitochondria, chloroplasts and a large central vacuole. Virginia Cooperative Extension lists these as the basic parts of plant cells, and UC Berkeley adds the plasmodesmata, small channels that link neighboring cells.

Why do cannabis plant cells lose firmness when plants wilt?

Each cell is held firm by water pressure in its vacuole pressing against the cell wall, called turgor pressure. When a plant loses more water than it takes up, the vacuoles shrink, the pressure drops and the leaves droop. UC Berkeley compares this with celery that has gone limp after losing water.

What do chloroplasts do inside cannabis plant cells?

Chloroplasts are the organelles that capture light. Virginia Cooperative Extension says they are the sites of photosynthesis and contain chlorophylls, which make leaves green, and carotenoids, which are yellow and orange. Most chloroplasts sit in the mesophyll cells inside the leaf.

Which cannabis plant cells divide to make new growth?

Cells in the meristems divide to make new growth. Virginia Cooperative Extension explains that the apical meristem at the tip of each root and shoot is the site of cell division that makes the plant elongate. New cells then expand as they take up water.

What does the vacuole do in a cannabis plant cell?

The vacuole is a large, fluid filled sac that stores water, ions, nutrients and wastes. UC Berkeley notes that it helps the cell keep turgor pressure, which keeps the plant firm. Nebraska Extension adds that cell turgor is driven by the large water filled vacuole.