b'Deficiency symptomsRosette formation is a result of zinc deficiency because the distance between the internodes is less stretched; the leaves are clustered around the stem. Also, the plant as a whole can be smaller (dwarfism) with smaller leaves that turn yellow and show red spots. The leaves are narrower and wavy. The root system and fruit size are also smaller.Lack of zincExcess symptomsAn excess of zinc is also expressed in growth inhibition, discolouration of the veins and yellowing in the top.Usually this yellowing is caused by a shortage of iron because an excess of zinc displaces the iron.BoronBoron is a negatively charged ion and cannot be applied in chelated form. The plant takes up boron in the form as boric acid or as boron hydroxide. It is not mobile in the plant, so just like with iron, it must be applied continuously.Boron has a function in cell division, ensures the transport of carbohydrates within the plant to growing plant parts and ensures the proper functioning of growth substances. 121'