Chlorine is actually one of the more plentiful elements on the entire planet. It is found all around us, abundant in soils, minerals, plants and even animals. Seawater is a major collector of dissolved chlorine. Oceans accumulate chlorine from dissolved mineral deposits that are transported from the continents by rivers. Plants take up chlorine in its monovalent ion chloride: Cl–
How long have we known about this essential element? Chlorine (Cl) was discovered in 1774, just two years prior to the signing of the Declaration of Independence. It was discovered when a pharmacist from Sweden released just a few drops of hydrochloric acid on a piece of manganese. When he did this, there was a greenish-yellow gas that was released and chlorine was discovered. The strange gas wasn’t identified as chlorine until 1810, but that was the original discovery of the chlorine gas. Chlorine was not determined to be essential for plant growth until 1954.
Chlorine has a number of benefits to plant growth. Many people make the common mistake of mixing up the plant nutrient chloride (Cl–) with the toxic molecular form chlorine (Cl2). Chloride is vital for many different plant functions, despite only being classified as a micronutrient. It is highly essential, combined with the element potassium (K+), for the proper function of the plants stomatal openings. Through the utilization of these two elements, the plant is able to control its internal water balance.
That is not the only role which chloride plays in plants. It also plays a very important part in photosynthesis, particularly in helping to control the hydrolysis process. It also aids in the process of cation balance as well as the transport of ions and nutrients throughout the plant system. There is even some research that shows chlorine can lessen the effects of fungal infections in a way that hasn’t yet been defined. Research continues to be done on the role of chloride in plant growth. Some people speculate that Cl– actually competes with nitrate uptake tending to promote the use of ammonium nitrate. This could explain the possible role that chloride plays in the suppression of some plant diseases because high plant nitrates have a strong association with the seriousness of plant diseases. Higher levels of nitrates are thought to make plants more vulnerable to pathogens.
In soils, chlorine is found in the soil as the highly soluble chloride anion. In that form it is extremely mobile except where it is held by soil anion exchange sites, a major factor that can affect chloride availability. Chloride, nitrate, sulfate, boron and molybdenum are all anions. Excessive levels of any one of these can interfere with the uptake of others. If chloride levels in a plant are too high, there is a possibility of toxicity. The signs and symptoms that accompany chloride toxicity are very similar to the problems associated with salt damage. They include leaves that are thicker and smaller in diameter, stunted plant growth, scorched margins between leaves.
Stubby roots, wilting, yellowing in the leaves or a bronzing are just some of the signs of deficient levels of chlorine. In order to combat Cl deficiencies and diseases or problems that are caused with insufficient Cl, check out the nutrition solutions offered by Dyna-Gro® (Grow™, Foliage-Pro®, Bloom™, All-Pro®). These complete nutrient solutions are the best way to eliminate Cl deficiencies. On the whole, chlorine toxicity is of wider concern than chlorine deficiencies.