In highly acid soils can result in toxicity. Boron is necessary for cell wall formation, membrane integrity and calcium uptake. The functions affected by boron include flowering, pollen germination, fruiting, cell division, water relationships and the movement of hormones. Zinc is essential to carbohydrate metabolism, protein synthesis and stem growth. Zinc deficiency may lead to iron deficiency.
Copper is concentrated in roots of plants and plays a part in nitrogen metabolism.
An over abundance of copper can cause toxicity. Molybdenum is a structural component of the enzyme that reduces nitrates to ammonia. Without it, the synthesis of proteins is blocked and plant growth ceases. Chlorine is involved in osmosis, the ionic balance necessary for plants to take up mineral elements and in photosynthesis. Nickel is an essential trace element for plants.