Boron Absorption and Translocation in Apple Rootstocks Under Conditions of Low Medium Boron

Abstract

The purpose of the experiment was to examine the differences in rates of boron (B) absorption and translocation to above‐ground plant parts by selected apple rootstocks under conditions of low medium B. The study was performed under greenhouse conditions on P22, P60, P14, M.26, and M.9 rootstocks grown for 180 days in pots filled with perlite and supplied with Hoagland's nutrient solution at 5 µmol B L⁻¹. The first B deficiency symptoms appeared on the youngest leaves of P22, P60, and P14 after 86–95 days of growth, whereas on M.9 and M.26 after 130–145 days. Boron deficiency signs on leaves were less severe on M.26 and M.9 than on the other ones. The M.9 and M.26 rootstocks produced more biomass and had higher total B concentrations in root, stem, and leaf tissues and also higher cell wall B status of root and leaves compared to those of P22, P14, and P60. Rates of absorption and B translocation to above‐ground plant parts were higher for M.9 and M.26 than for the other ones. These results indicate that on soils with high risk of B deficiency, apple trees should be grafted on M.9 or M.26.