Influence of three vesicular-arbuscular mycorrhizal fungi (Glomaceae) on the activity of specific enzymes in the root system of Cucumis sativus L.

The influence of three vesicular-arbuscular mycorrhizal (VAM) Glomus species on the activity of enzymes in the roots of Cucumis sativus was tested. Cucumber plants were grown in a split-root system, in which colonized and uncolonized roots of a single plant could be separated. The activity of the host root malate dehydrogenase (MDH), glucose 6-phosphate dehydrogenase (Gd), glutamate oxaloacetate transaminase (GOT) and glutamate dehydrogenase (GDH) was measured on a densitometer after separation of the host and fungal enzymes on polyacrylamide gels.The results showed that only minor changes in the activity of the host root enzymes occurred after VAM inoculation. Gd was stimulated by VAM and phosphorus, and one of the fungi decreased the activity of GDH in the host plant when both parts of the root system were colonized.