Osmosis is an important process for a marijuana plant. It keeps tension on the cells, thereby making the plant stand upright. Osmosis furthermore puts the leaves in the right position and the buds in optimal condition. It is also an important process for the absorption of nutrients. Osmosis is a natural phenomenon and doesn’t require any energy from the plant. You probably heard the term ‘reverse osmosis’ before: this is a way to create clean water from salt water. Increase your knowledge by carefully reading this article.
In this guide you will learn
What is osmosis?
Without osmosis, weed plants would lie flat on the ground with wilted leaves. Osmosis keeps tension in the cells. It’s a physical principle that also occurs outside plants. A liquid with dissolved substances attracts pure water. This principle can be demonstrated by taking two containers of water, separated by a semi-permeable membrane. The membrane allows water to go from the one container to the other, but the dissolved substances can’t.
if the concentration of dissolved substances is higher in one container than the other, water molecules move through the membrane to the container with the higher concentration. The container with the higher concentration is thereby diluted, just as long until an equilibrium is reached. This process doesn’t require any energy.
Cells are surrounded by membranes, which is also the case for the vacuole inside the cell. These membranes are also semi-permeable, so these let water through but not (most) dissolved substances. The cell stores nutrients, sugars, proteins and other substances in the vacuole. Together, these have a high concentration, so water flows to the vacuole in the osmotic process. This causes the cell to swell up.
This has a limit, because there’s also a cell wall, which provides back pressure and prevents the cell from bursting from the large amount of the absorbed water. In general, the cells are under tension, so the plant remains upright and the leaves can maintain a favorable position with respect to the light. Osmosis is also very important for opening and closing the stomata.
Absorption of nutrients through osmosis
The absorption of nutrients and the nutrient salts that are dissolved in it takes place through the roots of the marijuana plant. This process also takes place by means of osmosis. Osmosis is a physical process in which substances can move from one liquid – separated by a semi-permeable wall (cell membrane) – to another liquid. This occurs from the side with the highest concentration of nutrients to the side with the lowest concentration. This movement of ions is referred to as osmotic pressure.
The type and amount of substances on both sides of the cell wall is therefore important. Let’s keep it simple and assume that the liquid in the plant and in the water outside the plant only contains N (nitrogen), P (phosphor) and K (potassium) ions.
If the marijuana plant used nitrogen ions, the concentration inside the plant is lower than in the water outside. New nitrogen ions will be sucked in from the water. If the plant has sufficient potassium ions, so the concentration on both sides of the cell wall is the same, the K-molecules won’t move and stay where they are. If there are many more P-ions in the plant than in the liquid outside the plant, the phosphor will be sucked out of the plant, creating a deficit in the plant.
Reverse osmosis is used to take all nutrient salts from the water. It is used in dialysis, in laboratories and as a semi finished products of beer or sodas. It can also be interesting to us. Some geographical areas have tap water with many dissolved substances in it. The ratio of these substances is usually not interesting to a weed plant, for instance high chlorine concentrations. If you prefer to know exactly what you’re giving your plants, you can start with osmotic water and add nutrients to it. Reverse osmosis works as follows;
Two liquid containers are separated by a semi-permeable membrane. Water passes through the membrane in the direction of the liquid with the most dissolved substances. This can be countered by putting pressure on the water with the highest concentration. You can determine how high this pressure has to be in order to reach an equilibrium; so no water will pass through the membrane. This is called the osmotic pressure.
If you further increase the pressure, the water molecules actually go through the membrane to the container with the lower concentration. This is called reverse osmosis. By putting a lot of pressure on ‘dirty’ water, you push water through a semi-permeable membrane to the clean side, so you get cleaner water. This is demineralized water, which has an EC of almost 0 and a pH of 7. The other side will contain water with a very high salt concentration.
If you provide your plants with demineralized water, you have to look out for calcium and magnesium deficiencies. Most plant fertilizer producers assume you’re providing your plants with tap water, which contains a lot of calcium and magnesium. You filter these out with reverse osmosis. Do you know what the hardness of your tap water is?
Turgor and plasmolysis
A cell under tension puts pressure on the cell wall. This is called turgor pressure. Turgor is caused by the fact that the cell attracts water from neighboring cells or holes between the cells through osmosis. If the tension of the cell grows, the membrane of the cell stretches out until it hits the cell wall. This provides counter pressure. This system can be compared to a balloon you inflate in a box. The box puts counter pressure on the balloon.
It’s interesting to know that stomata have to learn to react to the moisture situation. Recent research at the University of Wageningen in the Netherlands showed that there is no need to close the stomata to limit loss of moisture when plants are cultivated under a constant high humidity. But they also won’t learn to close them, causing them to no longer react well under certain stressful circumstances.
Turgor is responsible for the firmness of plants. If the cell loses water because the osmotic value of the environment is higher, the turgor pressure decreases. This could even cause the membrane of the cell to detach from the cell wall, called plasmolysis. A cell that stays in this state for too long will die off.