The primary role of boron is in the cell walls. Boron provides cross links between polysaccharides to give structure to cell walls. Boron plays a role in the formation of sugar complexes, and proteins for translocation in plants. It is essential for cell division and development, aids in the use of nutrients, and regulates other nutrients. Boron can enhances the uptake of Ca, Mg, K. Helps cell membrane function, nodule formation, flowering, and development of seed and fruit set. Boron deficiency can reduce the quality and yield of crops. Organic matter is the most importing reservoir for soil boron. boron availability is decreased as the decomposition of organic matter slows. The bioavailability of boron is greatest between pH range of 5.0 and 7.5. Course sandy soils, and oversaturated soils can negatively affect the availability of boron. Boron deficiencies decrease the rate of water absorption, root growth, and translocation of sugars.
Symptoms of boron deficiency include:
*Poor seed and fruit set.
*break down of growing tip tissue.
*retardation of new growth, followed by death of long younger leaves.
*Yellowish to reddish yellow discoloration of the terminal foliage (leaf tip)
*inhibited development of Rhizobia in legume crops.
Factors affecting boron availability:
*low soil moisture, over watering (leaching)
* coarse textured, well drained, sandy soils and soils with low organic matter can reduce availability.
*soils with high organic matter, and greater water holding capacity will have greater availability.
*soil’s with high levels of available calcium may require additional applications of boron.
Available forms used by plants are H3BO3, B(OH)4-