Cellular Analysis of Ca, B, and Ca and B Deprivation

Root and shoot apical meristems are specialized areas where cell proliferation and organogenesis take place.  The role of Ca and B in the root development, and the interactions between Ca and B deficiency in nuclear morphology, cell proliferation and primary root growth were investigated. The absence of Ca, B, or both Ca and B greatly reduced primary root growth relative to control root growth within 12 hours. Nuclei in both Ca and Ca\B deficiency treatments showed a significant decrease in volume. Boron deficiencies initially resulted in an increased mitotic index (MI), concurrent with root apical meristem (RAM) distortion. Most of the increase in root diameter could be explained by an increase in the number of cell files in the cortex. Ca and B deficiencies together reduced both the MI and root tip distortion. Because calcium increased cell death but did not promote cell division, while boron increased cell division, the combination of Ca and B deficiencies appeared to attenuate symptoms of nutrient deficiency.