Abstract
Ascorbic acid is one of the major metabolite in higher plants cells which is known as effective factor when the cells enter to “S” phase from “G1” phase of cytokinesis. This metabolite has antioxidant activity and increases plant tolerance against stressors such as salinity, pathogens, ozone, UV rays, etc. The current study used the common cellular and histological methods to evaluate the effect of 0.05 to 2.5 mM ascorbic acid on vegetative meristems of Aloe barbadensis plants obtained from stem explants propagated in vitro culture conditions. Results showed that low concentrations of ascorbic acid (0.5 to 1 mM) increase mitotic index in apical meristem and root quiescent center (QC). Moreover, treatment with ascorbic acid increases cellular dimensions in cell elongation region of root and mitotic divisions in this region. In some measurements, it was clear that in addition to increase root length in plants treated with ascorbic acid, distance from root hairs
zone to root cap increases compared to the control, which is a logical conclusion from increasing cell elongation and divisions in cell elongation zone. Also, ascorbic acid increased production of secondary roots through stimulating cells of pericycle and increasing divisions in this region. Apical meristem of stem treated with ascorbic acid had more convexity homogenous with more chromophilic level. Increasing stem length and number of leaves in plants treated with ascorbic acid could be related to the high cells’ mitotic activity in stem apical meristem. Moreover, ascorbic acid could stimulate cell division, increasing area of meristem zone, and effective on severity of differentiation.
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