Stimulation of Waitea circinata by root exudates of Pinus cembroides

Abstract

Effects of root exudates from Pinus cembroides to Waitea circinata were studied by using paper chromatography. Each of 14 seedlings liberated an average of 175 μg of ninhydrin-positive substance and 133 μg of sugars in 35 days. From these, 14 amino acids, 4 sugars, and 3 organic acids were identified. The root exudate induced greatly increased mycelial growth over a wide temperature range, but sclerotia were produced only after 20 days between 15 and 20 °C. Each amino acid and carbohydrate, except threonine, valine, glycine, glutamic acid, lysine, γ-aminobutyric acid, and citric acid, stimulated vegetative growth. Neither basidia nor sclerotia developed on any nutrient medium. The sclerotia did not require exogenous nutrition for germination and initial growth. Germination percentage remained between 95 and 100 with each exudate component. All carbohydrate components, either singly or in combination, stimulated extension growth from sclerotia. Of 14 amino acids, only aspartic acid, glutamic acid, and leucine supported faster extension growth than the control (water agar). Temperature and pH influenced germination and growth, the optima being at 25 to 30 °C and pH 5 to 6.