تغییرات جمعیت اسپورهای قارچی میکوریز وزیکولار- آربوسکولار در خاک جنگل‌های طبیعی پسته در استان خراسان

In order to investigate variations of spore population, root colonization and also to determine mycorrhizal symbiosis in the root and rhizosphere of Pistachio trees (Pistacia vera) in natural forests, two study stations in Kalat (Chachaeh) and Sarakhs (Shorlogh) regions were selected. Sampling from soil and root of the trees were taken from under the canopy and from a depth of 30 cm. On a monthly basis. The roots were stained and the colonization rate and the variations of spore population were measured. Some soil characteristics including pH, moisture, organic material percentage and available phosphorus were determined, The correlation coefficients between the measured factors were calculated. The results indicated that vesicular – arbuscular mycorrhiza (VAM) was the only symbiotic mycorriza of pistachio trees. Average amounts of root colonization were 13% and 11% in Chahchaheh and Shorlogh stations, respectively. Also, average numbers of spores per 1 gram of dry soil in the above stations were 12 and 10, respectively. The correlation between the variation of spore population and colonization levels was positive but the correlation between spore population and soil moisture, organic material, available phosphorus and pH was negative.