Boron on in vitro growth and enzymatic activity of Blueberry

Abstract

Boron (B) is essential for plants metabolism and most culture mediums use the same concentration, but in different quantities this nutrient may provoke growth alterations. Thus, the purpose of this study was to examine the effect of B on in vitro growth of blueberry in three experiments. The first experiment of multiplication (evaluated at 90 days) used 3 concentrations of 2-isopentenyladenine-2iP with 4 concentrations of boric acid-BA (factorial scheme 3x4). The second used 4 concentrations of BA and 1 concentration of 2iP and the third (rooting) used 4 concentrations of BA and 1 concentration of indolbutyric acid-IBA both evaluated at 180 days (unifactorial scheme). All the experiments had 4 replicates with explants. 6.2 mg L-1 of B and 5.0 mg L-1 of 2iP generated the highest shoot quantity (18.4, 25.5 respectively). From the interaction of these concentrations, there was the highest activity of POD and PPO enzymes. Under B deficit was seen a larger number of shoot-tip necrosis (9), red leaves (31) and high activity of the PAL, IAAO and POD enzymes. With IBA the correlation between IAAO and the roots’ growth was positive, showing that blueberry rooting depends of both B and IAAO regulation.