Effects of exogenously-applied L-ascorbic acid on root expansive growth and viability of the border-like cells

Functions of exogenous L-ascorbic acid in plant roots are poorly understood. Recent study by Makavitskaya et al. (doi.org/10.1093/jxb/ery056) has demonstrated that exogenous ascorbate can be released from roots in response to salt stress, and can trigger elevation in the cytosolic free Ca²⁺. Here, we report that exogenous ascorbate significantly modifies root elongation in <i>Arabidopsis thaliana</i>. Using a medium exchange technique, we have shown that 10-100 µM ascorbate induces small but significant increase in root elongation while higher levels cause its dramatic decrease. Root border cells of <i>Pisum sativum</i> have been losing viability twice faster in the presence of ascorbate that under control conditions, as tested by the confocal microscopy and a combined staining with propidium iodide and fluorescein diacetate.