Boron

Abstract

Boron (B), a metalloid element, is atomic number 5 of periodic table. Element B and some B compounds have industrial values. B essentiality is proven in some living organisms including plants, but probably in human. At present, the only role of B in plants is demonstrated as the structural maintenance of cell wall. Soil B, as boric acid, is acquired through roots and then distributed around the plant via the passive and active transport pathway. To adapt variations in the environmental B status, the active B transport system is tightly regulated at the molecular level in plants. In agriculture, both deficient and excess levels of soil B impair plant growth, resulting in the reduction of quantity and quality of crops. The major causes of B toxicity in plants contain oxidative stress, metabolism alteration and deoxyribonucleic acid damage. Several plant traits/genes that ensure tolerance to B stress have been isolated. Key Concepts: Boron has numerous biological functions in almost all living organisms including plants although its biochemical importance is poorly understood. B is widely distributed in the earth, and its main form in soils is boric acid that is available for plants. B availability in soils depends on factors such as soil type and climates, and it is a key determinant for the crop yields in agriculture. Plants uptake and distribute B via two distinct pathways: passive diffusion and active transport mediated by B transport molecules. The molecules working in the active B transport system are tightly regulated dependently to the environmental B conditions to promote B acquisition under limited B supply or to avoid accumulating toxic levels of B in plants. The active B efflux from cells to soils or outside of cells and the protection of cellular mechanism from B attack are key molecular processes for B‐toxicity tolerance in plants.

Boron Fertilization of Irrigated Alfalfa in Montana

“…Boron is an essential micronutrient for plant growth and development (Dear and Weir, 2004). Boron deficiency impairs plant growth and reduces quantity and quality of crops (Sakamoto, 2012). Boron helps in the translocation of sugars, carbohydrate metabolism, hormone action, nucleic acid synthesis, reproduction of plants, root growth, and germination of pollen (Dell and Huang, 1997;Howe, 1998;Devirian and Volpe, 2003).…”