FLOW CYTOMETRIC ANALYSIS OF BRASSICA-JUNCEA CELL AND POLLEN CULTURES TREATED WITH DESTRUXIN-B, A TOXIN PRODUCED BY ALTERNARIA-BRASSICAE

A rapid and reliable flow cytometric method of determining plant cell and pollen grain viability upon treatment with Alternaria brassicae pa thotoxin (destruxin B) has been standardized on the basis of light sca ttering properties of cells of Brassica juncea cv. Kranti stained with fluorescein diacetate. Data on relative fluorescence of cells treated with 60 and 120 mu g destruxin B ml(-1) were collected. The frequency distribution of fluorescence and histogram statistics showed a gradua l loss of fluorescence in destruxin B-treated cells. The cell viabilit y was 81% in untreated cells and 39% in 120 mu g destruxin B ml(-1) tr eated cells after 96 h of culture in the Murashige and Skoog medium. T hese observations were similar to those obtained by manual counting wi th a light microscope using Evans blue. Optical sectioning with a conf ocal laser scanning microscope revealed plasmolysis of destruxin B-tre ated cells. Viability of pollen grains of B. juncea cv. Kranti treated with destruxin B was also determined on the basis of their relative f luorescence. (C) 1996 Academic Press Limited