Study on the vesicular-arbuscular mycorrhizal fungi populations in pistachio orchards of Kerman Province.

摘要

Vesicular arbuscular mycorrhizal fungi (VAMF) are able to make a symbiotic relationship with many plants and cause optimum plant growth by increasing absorption of some nutritional elements. In this study, the spore population of VAMF in the rhizosphere soil of pistachio trees and the percentage of mycorrhizal root colonization have been surveyed during 1995-98 in pistachio orchards of Rafsanjan, Zarand, Sirjan and Shahr-e-Babak in Kerman province, Iran. Spores of VAMF were extracted and counted in 100 g of soil samples by wet-sieving followed by sucrose centrifugation. Also, root samples were cleaned and stained for evaluation of mycorrhizal root colonization using the non-systemic root scanning procedure. Results showed that VAMF have a symbiotic relationships with roots of Pistacia vera in the majority of investigated pistachio production areas. Glomus fasciculatum was observed in Kerman and Zarand orchards and Glomus spp. were the dominant species in all pistachio orchards of Kerman province. For the first time, two VAMF species, Gigaspora decipiens and Glomus gerdemanni [Archaeospora gerdemannii] were reported from the soils of this area. Spore population was detected to be high in those areas with shorter irrigation intervals, low salinity and moderate climatic condition. The percentage of root colonization of different pistachio rootstocks (Pistacia khinjuk, P. mutica, P. vera) with different degrees of incidence (C1-C5) were determined in this study. Chemical analysis of soil samples showed that phosphorus concentration has a negative relationship with VAMF population, i.e. increasing phosphorus in soil is followed by decreasing VAMF population..