Boron deficiency

• Role in the plant: boron regulates the transport of sugars throughout the membranes and also plays a key role in cell wall formation and cell division and for the metabolism of auxins.

• Symptoms of deficiency: a typical symptom consists of the death or delayed development of the growing buds on foliage or tubers. The terminal bunches of the plants turn yellow and necrotise (photo 1). The plants have a bushy appearance and the top leaflets are thickened and may curl upwards (photos 2 and 3). The plants may have a slow emergence and foliar development or may even be stunted, because of the shortening of the internodes. In severe cases, yield reduction may occur.

           Toxicity: strong leaf deformation, similar to that caused by hormones, may be induced by severe boron toxicity.