Abstract

The degree of infection of Juniperus procera roots by arbuscular mycorrhiza fungi (AMF) is highly indicative of the response of plants to environmental stress and is affected by the presence of flavonoids in the roots. However, relatively little is known about the relationship between soil textural components (sand, clay, silt content) and the percentage of AMF in the field soil. The aim of this work was to determine the relationship between soil textural components, content of flavonoids and AMF infection in the roots of J. procera. A significant correlation was found between AMF in the roots of J. procera and the soil textural components. A positive or negative correlation depended on each composition of soil texture. A negative correlation was found between the percent of AMF in the roots and the amount of coarse sand, fine sand and clay, while a positive correlation existed between the percent of AMF and silt. The degree of colonization with AMF was higher when the quantity of coarse sand was lower (r = -0.83). Similar trend was also observed with fine sand (r = -0.84), and clay (r = -0.83). On the contrary, root colonization with AMF was higher when the quantity of silt was higher (r = 0.92). This study demonstrated that the proportion of silt in the soil and the amount of flavonoid are strongly and positively correlated with AMF infection in the root of J. procera in Saudi Arabia.

Key words: Arbuscular mycorrhiza fungi, Juniperus procera, flavonoids, soil texture