Water is an absolutely essential component of all lifeforms. Water plays seven important roles in plants. Herbaceous plants have an average fresh weight of 80-90 percent water, while woody plants have an average fresh weight of over 59 percent water. The evaporative process of transpiration drives the movement of water from the soil into a plant’s roots and through the plant. Transpiration is simply the evaporation of water via small pores called stomata in a plant’s leaves. Transpiration is an essential part of a plant’s growth and development.
Water is required for photosynthesis, which turns sunlight, carbon dioxide, and water into carbohydrates that humans and other animals may consume for energy. Carbon dioxide can also enter the plant as water vapour flows out of the stomata during transpiration. The movement of carbon dioxide (another vital component of photosynthesis) into the plant is facilitated by the transpiration of water vapour out of the open stomata. Transpiration also helps to cool the plant and causes water to flow upward through it.
Water is pushed up from the soil through the roots and into the plant when it transpires or evaporates through the plant’s stomata. Minerals and nutrients from the soil are carried by the water, which are necessary for plant growth.
THE FUNCTIONS OF WATER IN PLANTS
Solvent:
Water is the universal solvent, as it dissolves more substances than any other liquid.
As a result, water is the medium in which biochemical reactions and chemical processes are dissolved in the cell.
Water may flow from place to place in the plant because cell membranes and cell walls are both permeable to it.
Water becomes a continuous liquid throughout the plant, filling the central section of mature cells’ vacuoles, the walls, and the majority of the intercellular space. Because of the necessity for carbon dioxide exchange with the air, the intercellular spaces of leaves are filled with gas.
Reactant
Water is a reactant in the cell’s biochemical processes.
One of them is photosynthesis, in which water supplies electrons that are eventually used in the reduction of carbon to carbohydrate and hydrogen protons that are used in the formation of ATP [adenosine triphosphate]. The oxygen produced in photosynthesis is also derived from water.
In the breakdown of plant food reserves like starch, water is also a reactant. Water atoms are inserted between the glucose units of the starch polymer during starch hydrolysis, converting starch to sugar.
Transport:
Water flow transports minerals taken from the soil through the root, up the stem, and throughout the plant.
Water also transports carbohydrate molecules generated during photosynthesis throughout the plant.
Growth:
The vacuoles of freshly produced cells are dispersed and small during cell division. Minerals are taken in and deposited in these small vacuoles. Water diffuses into the small vacuoles, causing them to expand and create pressure inside the cell. This pressure causes the young cells’ plastic walls to expand, resulting in cell development. The vacuoles eventually coalesce (merge and join) into a central vacuole, and the walls thicken to the point where they lose their plasticity, so the cell no longer grows but maintains water pressure inside the cell at maturity.
Turgidity:
The force of water pressing against the interior of the cell walls helps mature cells keep their shape. If the pressure is removed (for example, due to excessive evaporation, death, or exposure to salt solutions), the cells lose their turgidity and become flaccid.
Many tissues, such as leaves and annual plants that lack woody or other supporting components, are shaped by the turgidity of cells.
Thermal stability:
Water requires more calories of heat to increase its temperature than any other common substance.
As a result, plants, which are largely water, may absorb a lot of heat (for example, from sunshine) and only slowly gain temperature.
Similarly, the temperature of water (for a plant) must be dropped by the same amount of calories; hence, plant temperature can remain close to air temperature during brief cold periods.
Plants can sustain a more consistent temperature than the air because of their high-water content.
Root Growth:
Root growth reaches new soil, water, and mineral stores by growing into them. Water and mineral absorption will be affected by any factor that affects root development.
HARMFUL EFFECTS OF WATER STRESS ON PLANTS:
- WILTING: Wilting may be the first visible indicator of water stress. The plant will begin to lose its shape and droop. Wilting is a simple approach to detect water stress. It is a plant’s initial indication of water stress. If a plant is wilted but still green, it can be saved if it is detected and watered as soon as possible. A plant that has wilted and become brown, on the other hand, is difficult to recover.
- REDUCED PHOTOSYNTHESIS: This indicates that plants will produce fewer blooms and fruits. Because water is the most important component in the food production process. A plant’s decreased food production is hard to detect.
CONCLUSION
Water is the most important nutrient for plants, accounting for up to 95 percent of their tissue. Water is essential for a seed to sprout, and water transports nutrients throughout the plant as it grows. Water performs a number of critical activities in plant tissues.
Water is required for all metabolic processes and biological activities that occur within the plant. Water is required for the life of every cell in the plant. The plant cannot undertake photosynthesis, respiration, or food translocation to other regions of the plant without water. More critically, plants cannot absorb nutrients if there is no water in the soil. A plant’s survival becomes increasingly difficult.