Fluorine for Plants: Energy Extractor?
Fluorine (F)
Is fluorine essential for plants – an energy extractor? (the question is under discussion)
The necessity of fluorine for the life processes and metabolism of plants is under discussion. At the same time, it has been noted that the visible stimulation of some isoenzymes (for example, acid phosphatase or dehydrogenase) after fumigation of plants with hydrofluoric acid may lead to the inhibition of other enzymes.
In a number of plant species, fluorine is part of fluoroacetate and is responsible for the conversion of chloride into isocitrate or oxaloacetate and acetyl-CoA, and as a result – for providing energy to cells.
Fluorine content in plants is 0.001 mg% (by weight).
Soluble forms of fluorine are passively absorbed from the soil by plant roots and, apparently, are easily transported within plant tissues. This is confirmed by data on the extraction of fluorine by plants in fields irrigated with water containing fluorine. It has been established that the volume of fluorine absorption from the nutrient medium by alfalfa and wheat positively correlates with its concentration in the medium; fluorine compounds accumulate predominantly in plant seeds (up to 3250 mg/kg dry weight when the fluorine content in the medium is 50 mg/kg).
Although the given example shows that plants can relatively easily extract fluorine from contaminated soils, the bioavailability of soil fluorine is significantly lower than the bioavailability of fluorine from airborne compounds. The accumulation of airborne fluorine by plants depends on many factors, but is particularly influenced by its concentration in the atmosphere and the duration of exposure.
Although the given example shows that plants can relatively easily extract fluorine from contaminated soils, the bioavailability of soil fluorine is significantly lower than the bioavailability of fluorine from airborne compounds. The accumulation of airborne fluorine by plants depends on many factors, but is particularly influenced by its concentration in the atmosphere and the duration of exposure.
Signs of fluorine deficiency in plants are not described in the literature.
Data on the phytotoxicity of fluorine upon root absorption are lacking. At the same time, it has been established that airborne fluorine, especially in the form of hydrofluoric acid, is very toxic to plants. The most significant impact of fluorine on plant metabolism manifests in the reduction of oxygen absorption rates, respiratory disturbances, decreased nutrient assimilation, reduced chlorophyll content, inhibition of starch synthesis, inhibition of pyrophosphatase function, alteration of cellular organelle metabolism, damage to cell membranes, destruction of DNA and RNA, as well as in the synthesis of fluoroacetate – the most toxic fluorine compound.
Medicinal plants containing fluorine:
• alfalfa Medicago sativa L., Fabaceae (herb);
• garden spinach Spinacia oleracea L., Amaranthaceae (leaves).
• alfalfa Medicago sativa L., Fabaceae (herb);
• garden spinach Spinacia oleracea L., Amaranthaceae (leaves).