Effect of arbuscular mycorrhizal fungi and Pseudomonas fluorescence on vegetative growth of pistachio seedlings (Pistacia vera cv. Qazvini) under four different irrigation regimes

In order to investigate the symbiotic effect of arbuscular mycorrhizae (Glomus mosseae) and a bacteria (Pseudomonas fluorescence) on vegetative growth of pistachio seedlings (Pistacia vera cv. Qazvini) under drougth stress، a greenhouse experiment was conducted using four drougth stress levels (100% FC as control، 75، 50 and 25% FC) and four levels of biofertilizers (non mycorrhizal and non bacterial plants as control، mycorrhizal treatment، bacterial treatment and a mixed treatment of both). In the experiment، application of bacteria in different drougth stress levels could not affect root colonization with mycorrhizae whereas increase in root colonization percentage was observed along with increase in drougth intensity. The highest values of leaf area and number، stem height and dry weight of leaf and stem were obtained with 50% FC in comparison with control. Root lenght was increased with increase in drougth stress levels. Dry weight of stem، root length and leaf area were more in mycorrhizal and mixed treatments in comparison with control. The least values of leaf area and number، stem diameter، root length and stem dry weight were observed in bacterial treatment in comparison with control. Root volume and dry weight were maximum in bacterial treatment with a significant difference with control. Totally، it can be concluded that the mixed treatment had the most effect on vegetative growth of pistachio seedling under different drougth stress levels and from drought point of view، 50% FC was the best treatment which improved the most vegetative growth parameters.