Effect of Potassium on Sugar Uptake and Assimilation by Bean Rust Germlings

ABSTRACT

Induction of differentiation of uredospore germlings of the bean rust fungus (Uromyces phaseoli) by potassium salts and certain other compounds including sugars suggested that K⁺ may act by mobilizing organic substrates for use in metabolism. Instead, potassium ions inhibited uptake of exogenous sugars due to the activity of a plasmalemma proton pump acting under the influence of external K⁺. Germling differentiation appears to be indifferent to assimilation of exogenous substrates as metabolites.

Key Words:

• appressoria
• bean rust fungus
• infection structures
• germling differentiation