GROWTH OF A SOIL-BORNE PLANT PATHOGEN SCLEROTIUM ROLFSII UNDER CHROMIUM(III) STRESS

Abstract

Tolerance of plant pathogens to heavy metal stress is an important area of research that has been rarely explored in Pakistan. The current research work was carried out to investigate the impact of Cr(III) on growth of Sclerotium rolfsii Sacc., the cause of collar rot of chilli (Capsicum annuum L.). Laboratory bioassays were conducted in using solid as well as liquid malt extract growth medium amended with 14 different concentrations (0, 5, 10, 20, 30, …,100, 150, 200, 300, 400, 500 ppm) of Cr(III). Growth medium flasks with different concentrations of Cr(III) were inoculated with the pathogen and incubated for 7 days at 25±2 ^oC. Results showed that radial growth of S. rolfsii on solid medium and its biomass on liquid medium were significantly decreased with the increase in concentrations of Cr(III) up to 100 ppm, while fungus was unable to grow at concentrations above 100 ppm. There was a linear relationship (R² = 0.9242) between Cr(III) concentrations and fungal biomass on liquid medium, and a non-linear relationship (R² = 0.9264) between Cr(III) concentrations and fungal radial growth on solid growth medium.