Cobalt for Plants: Nitrogen Fixation
Cobalt (Co)
For the plant – active symbiotic nitrogen fixation.
In plants cobalt affects the accumulation of nitrogenous substances (possibly also in non-nodular plants) and carbohydrates, intensifies their flow from vegetative organs to generative ones, enhances the intensity of respiration and photosynthesis, promotes the formation of chlorophyll, and reduces its degradation during the dark period of the day.
Cobalt also increases the overall water content in plants, especially during drought, and is absolutely necessary for the reproduction of nodule bacteria and their nitrogen fixation. In plants, this element is found in ionic form and as part of vitamin B12 (about 4.5%). Plants, like animals, do not synthesize vitamin B12 themselves. It is produced by bacteria in the nodules of leguminous plants and is involved in the synthesis of methionine.
Under natural conditions, the weakening of plant growth due to cobalt deficiency is practically not observed. The deficiency of cobalt in plants is mainly considered in connection with the necessity of this element for grazing animals. A lack of cobalt in feed is observed when its content in soils is less than 2.5 mg/kg. Critical levels of cobalt content necessary for the nutrition of grazing animals are estimated to be approximately 0.08–0.10 mg/kg dry mass.
Under the influence of increased cobalt content in the soil, the appearance of indicator plants changes: giant plants appear in two-seeded alyssum Alyssum biovulatum N. Busch (Brassicaceae) and species of cotoneaster Cotoneaster Medik. (Rosaceae), which are 3–5 times taller than usual, while in species of larch Larix Mill. (Pinaceae), cones form 2–3 times per season, turning white in April, then becoming pink, yellow in June, green in July, and then brown.
The highest cobalt content among plants is found in algae: approximately 0.025 mg% (by weight).
Medicinal plants containing alkaloids selectively accumulate cobalt.
Medicinal plants containing alkaloids selectively accumulate cobalt.
Cobalt hyperaccumulator plant – cobalt crotalaria Crotalaria cobalticola P.A. Duvign. & Plancke, Fabaceae (herb, ash content – 1–3%).
Medicinal plants containing cobalt:
• plants of the legume family Fabaceae Lindl.;
• plants of the grass family Poaceae (R.Br.) Barnhart;
• yellow water lily Nuphar lutea (L.) Sm., Nymphaeaceae (rhizome with roots);
• deadly nightshade Atropa belladonna L., Solanaceae (rhizomes with roots, herb, leaves);
• marsh cudweed Gnaphalium uliginosum L., Asteraceae (herb);
• greater celandine Chelidonium majus L., Papaveraceae (herb);
• wild strawberry Fragaria vesca L., Rosaceae (leaves – 4.7 µg%);
• common lingonberry Vaccinium vitis–idaea L., Ericaceae (leaves, ash content – 77 g/t);
• chamomile Chamomilla chamomilla (L.) Rydb., Asteraceae (inflorescences);
• species of hawthorn Crataegus L., Rosaceae (fruits – 2.4 µg%);
• hybrid rowan Sorbus Hybrid L., Rosaceae (fruits – 2.5 µg%);
• common viburnum Viburnum opulus L., Caprifoliaceae (fruits – 28–29 µg%);
• Siberian apple Malus baccata (L.) Borkh., Rosaceae (fruits – 3 µg%);
• species of rose Rosa L., Rosaceae (fruits);
• bird cherry Padus racemosa (Lam.) Gilib., Rosaceae (fruits).
• plants of the legume family Fabaceae Lindl.;
• plants of the grass family Poaceae (R.Br.) Barnhart;
• yellow water lily Nuphar lutea (L.) Sm., Nymphaeaceae (rhizome with roots);
• deadly nightshade Atropa belladonna L., Solanaceae (rhizomes with roots, herb, leaves);
• marsh cudweed Gnaphalium uliginosum L., Asteraceae (herb);
• greater celandine Chelidonium majus L., Papaveraceae (herb);
• wild strawberry Fragaria vesca L., Rosaceae (leaves – 4.7 µg%);
• common lingonberry Vaccinium vitis–idaea L., Ericaceae (leaves, ash content – 77 g/t);
• chamomile Chamomilla chamomilla (L.) Rydb., Asteraceae (inflorescences);
• species of hawthorn Crataegus L., Rosaceae (fruits – 2.4 µg%);
• hybrid rowan Sorbus Hybrid L., Rosaceae (fruits – 2.5 µg%);
• common viburnum Viburnum opulus L., Caprifoliaceae (fruits – 28–29 µg%);
• Siberian apple Malus baccata (L.) Borkh., Rosaceae (fruits – 3 µg%);
• species of rose Rosa L., Rosaceae (fruits);
• bird cherry Padus racemosa (Lam.) Gilib., Rosaceae (fruits).
The best source of cobalt for correcting its imbalance in humans is all species of rose.