Boron

There are long lists of “postulated roles of B” for higher plant growth and development. Gauch and Dugger (1954) in their thorough review listed 15 potential roles for B in plants, and later Parr and Loughman (1983) listed 10 potential roles. However, many of these “postulated roles” of B can be eliminated as “secondary” by considering the “timing” of the deficiency treatments. Only short term experiments are meaningful when one is trying to establish a major role of B in plants. In fact, now that B has been established as a component of the (RGII) fraction of cell wall pectin, it is much easier to explain many of the “postulated” roles. But the question remains, are there important roles of B beyond (RGII) in cell walls? Again, one must focus on rapid responses to B deficiency.

http://5e.plantphys.net/article.php?id=403