Histochemical localization of exogenous ascorbic acid in the pericycle nuclei of Vicia faba

SUMMARY

A more abundant production of lateral roots in Vicia faba seedlings was observed after treatment with ascorbic acid, an effect which was primarily due to enhanced pericycle cells activity. The histochemical localization, as revealed by the reduction of silver nitrate into metallic silver, demonstrated that a wide stain intensity is detectable in the pericycle nuclei in a zone ranging between 2000 and 2500 μm from the root tip. In this context, the high ascorbic acid content seems to be related to the onset of the metabolic activation for the production of lateral roots primordia. On the basis of these observations, it may be speculated that exogenous ascorbic acid, which is known to be involved in nucleic acids metabolism, might be both accumulated and utilized by the nuclei of pericycle cells.

Key words:

• pericycle
• ascorbic acid
• lateral roots
• Vicia faba