Azide treatment enhances cell-to-cell diffusion in staminal hairs ofSetcreasea purpurea

Abstract

The effect of azide on the diffusion of fluorescent molecular probes was examined in staminal hairs ofSetcreasea purpurea. Staminal hairs were treated with azide before being microinjected with fluorescent molecular probes of different size, charge, and structure. The cell-to-cell movement of these fluorescent molecules was videotaped, analyzed, and coefficients of diffusion through plasmodesmata (D) and coefficients of diffusion across the tonoplast (k1) were calculated and compared to those of untreated cells. The D was larger and the k1 was smaller for many fluorescent probes in azide treated cells compared to normal, untreated cells. In addition, the cell-to-cell diffusion selectivity based on molecule structure, size and charge no longer existed in azide treated cells. An average D of 3.3×10−8cm2/s and an average k1 of 2.9×10−7/μm2/s was calculated for the molecular probes tested. New size limits for permeation were observed indicating that the plasmodesmata had become enlarged.