Plant Water Relations

An Introduction to Osmosis 

The relation between plants and water helps us learn how plants take care of the process of hydration of cells. The process starts with absorbing water from soil with the help of their roots, transportation of water to other parts of the plant, and transpiration, i.e., giving water vapours off through the leaves. The osmosis biology is one function of water in plants in which the water enters and exits a cell. The osmotic potential is the permeability of water which is relative to pure water. Therefore, the purest form of water is regarded to have an osmotic potential of zero. 

The Water Intake Processes

Water is one of the most important requirements for plants. A plant's body consists of approximately 90% water. Green plants carry out processes like photosynthesis in the presence of water; they use up carbon dioxide from the atmosphere, and during the process of photosynthesis, they give out oxygen. 

Water also helps in absorption of minerals from the soil and transportation of mobile nutrients like nitrogen in the form of nitrate, potassium, phosphorous in the form of phosphate, chlorine, magnesium, zinc, calcium, molybdenum, iron, sulfur, copper and boron. 

Water also helps in keeping up the turgidity of cell walls. Water is also essential for the enlargement of cells with the help of turgor pressure and cell division; it finally helps in the growth of plants. Water transpires from the stomata of the leaves; this process helps in creating low pressure in the vacated area, allowing more water to occupy the place; it helps the constant supply of mobile nutrients. Another important use of water in plants is that the transpiration process helps the plant not to dry out. Moreover, in processes like nitrogen fixation, water is integral.

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Osmotic Potential and Water Potential

The molecules of water have a specific amount of potential energy. The energy contained by the water molecules can be calculated in terms of the volume and purity of water. The purest form of water with a specific volume at a given temperature can be used as a reference for other variables. 

Water potential is the tendency of water to flow or move from one place to another depending on several mechanisms like gravity, osmosis, mechanical pressure, capillary action etc. 

Osmosis is the process in which the water moves through a semi-permeable membrane. In this process, water moves from the high concentration region to low concentration region until it attains equilibrium. These various forms of potentials help us study the relationship between plants and water. 


In the imbibition process, the seed, semi-permeable or permeable substances like wood or colloid absorb water from the soil. E.g., if you have hay or wooden pieces in the field in which you have grown a farm, you will have to use more water on a regular basis because the dry grass and wooden pieces imbibe some water. Apart from the fact that these things are permeable, their surface area, their support of capillarity and surface tension also contribute to the imbibition process.

Water Potential as a Scientific Study

Too much watering of plants can be detrimental. Too much water eventually gets evaporated leaving all the minerals including salts at the surface of the soil. It may render the soil barren. On the other hand, using less water can be less effective in the growth of plants. 

The study of water potential helps in understanding how water potential in plants can be used for conservative and effective use of water. In general conditions, where the gravity is constant and the atmospheric pressure does not have any considerable effect on the water potential, we can study the osmotic potential.  

Along with other environmental factors like the temperature, humidity, presence of imbibing materials etc. it can help us understand the total requirement of water for a given nursery of plants. Concepts like growing plants in space and on other planets, where gravity and atmospheric pressure are not the same as on earth, are of great interest for scientists. In such situations, the absorption, transportation and transpiration of water can be adjusted with a better insight on the plant water relationship. 

FAQ (Frequently Asked Questions)

Question 1: How Does the Imbibition Process Help in Studying the Germination Process?

Answer: The imbibition process involves the absorption of water by the seeds through their microscopic holes. It may also refer to the intake of water by other permeable, semi-permeable substances and colloids. There are various applications of the imbibition process. The amount and purity of the water used, the looseness of the soil and presence of any possible imbibing item and so on may affect the germination process. These aspects affecting the imbibition process can be meticulously studied to predict the outcome of the germination process. Moreover, it can be used to find relations with other variables like the presence of certain minerals affecting a plant's growth.

Question 2: How Does the Relation of Plants to Water Potential or Osmotic Potential, in Particular, Help Us?

Answer: Water potential is an intricate study of the dynamics of water, various factors affecting the dynamics, and their overall consequences on the growth of the plants. Osmotic potential is one such aspect of water potential. In osmosis, water is absorbed by the plants through its roots. The subsequent processes are transportation and transpiration of water. The study helps us to understand as to what all factors affect the whole process of carrying water through the plants. It also helps us in understanding that if one variable is changed then how the other variables can be changed to carry out the process.