In the roots of B-deficient plants, we observed more lateral root initiation and higher-order lateral root branching. In addition, apical dominance was reduced and lateral buds were activated in the shoot of tobacco plants grown under B deficiency conditions (data not shown). Both of these symptoms resulted likely from impairment of the activity of root and shoot apical meristems. Boron is essential for actively growing regions of plants such as root tips (Martín-Rejano et al. 2011) and is important for development of leaf primordia in buds (Marschner 1995). Rosetting and stunting of plants observed in tobacco plants in this work has been reported to be a common B deficiency symptom following reduction of cell numbers in the apical growing regions of alfalfa, clovers and other legumes (Marschner 1995). Impairment of leaf development in the shoot apical meristem could be judged by strong malformation of young developing leaves and uneven curling of leaf blades observed typically in turnip plants and suggests that B is required for normal development of leaf primordia.