What Happens When a Plant Is Moved From Freshwater to Salt Water?

Plant Life Processes

• Photosynthesis is a plant process by which the plant produces food from light, water and carbon dioxide. Respiration is the process by which the same plant burns food and produces water and oxygen. The third plant process is transpiration. Transpiration is the process that regulates water movement into and out of the plant's cells. Without transpiration a plant begins to wilt and show signs of malnutrition. Water dissolves minerals and is their mode of transport throughout a plant. Improper water regulation results in mineral deficiencies. Water also cools plants. Internal temperature regulation is necessary for a plant to complete the other processes necessary for its health. Transpiration relies on osmosis, a natural reaction that occurs when a plant is exposed to salt and water.

Osmosis

• Plants take in water and lose water via osmosis. An osmotic response is one that moves water across permeable membranes from an area of low salt concentration to an area of higher concentration. Osmosis does not stop until salt is equally dissolved on both sides of the permeable membrane. When a plant that is adapted to freshwater conditions is placed in salt water, the plant will become dehydrated and die. Freshwater will move across the permeable membrane into salt water but, since the small amount of freshwater within the plant will never fully dilute the salt water surrounding it, the plant will lose all of its freshwater into the surrounding salt water solution. Unable to perform vital life processes, the plant will die.

Freshwater Plants

• The majority of plants, from petunias, to bluegrass, to waterlilies are freshwater plants. They have not adapted to high salt concentrations and will exhibit lackluster growth or death when exposed to salty solutions, like animal urine, de-icers and highly concentrated fertilizers. Salt water will also damage these plants. The amount of damage a plant experiences is dependent upon the amount of salt to which the plant is exposed and the plant's own resistance to salty conditions. Some freshwater plants, like live oak, silver button bush, English ivy and creeping fig, are extremely salt tolerant and are safe to plant near coastlines or salt marsh regions.

Salt Water Plants

• Ocean plants like phytoplankton, algae and kelp are able to thrive in high-salt conditions because they have had thousands of years to adapt to briny environments. These plants are able to extract water and carbon dioxide from ocean water. They then use this water, gas and nutrients to perform photosynthesis, respiration and transpiration. When these plants are taken from their home environment and placed in open air, or in freshwater, they will fail to thrive in much the same way as freshwater plants fail to adapt to high salt conditions.