Effect of Arbuscular Mycorrhiza Fungi and Pseudomonas fluorescent bactria on Nutrient Uptake of Pistachio Seedling (Pistacia Vera Cv. Qazvini) under Four Irrigation Regimes

Pistachio is one of the most important products exported from the country, which due to the low rainfall, its production is faced with water deficiency in Iran. One of the strategies adopted to deal with water deficiency and drought stress in recent years is the use of mycorrhizal fungi and phosphate solubilizing bacteria. Therefore, to study the effect of co-inoculation of arbuscular mycorrhizal fungus Glomus mosseae and Pseudomonas fluorescens P52 strain bacteria on nutrient uptake of pistachio seedling (Pistacia vera cv. Qazvini) under drought stress, a greenhouse experiment was conducted using four levels of drought stress (%100 Field capacity (FC) as control and 75, 50 and 25 %FC) and four levels of biofertilizer (plant without mycorrhizae and bacteria as control, mycorrhizae alone (100 gr of mycorrhizal inoculum in every pot), bacteria alone (two ml of the bacterial suspension in every pot) and mycorrhizae and bacteria combination (100 gr of mycorrhizal inoculum and two ml of the bacterial suspension in every pot)) in a completely randomized design as factorial with four replications. The experiment was carried out between the years of 2010 to 2011 on 3-months old seedlings with three seedlings per pot. In this experiment, bacteria inoculation in different levels of drought had no significant effect on root colonization by mycorrhizae, but regardless of bacterial treatment, an increase in drought intensity had a promotive effect on root colonization. The amount of phosphorus was increased using biofertilizer and in many cases the greatest amount of phosphorus was obtained in mycorrhizae and mixed treatments under 25 and 50% FC. The K+ content of shoot was maximum in the mixed treatment. The greatest amount of root Ca+ was recorded under 25% FC. Drought stress caused a significant increase in micronutrients compared with control at 25% of field capacity, but was ineffective in the roots. In conclusion, the results of this study showed that in many cases the combination treatment of mycorrhizae and bacteria increased drought resistance in seedlings by increasing nutrient uptake and especially phosphorus in the drought stress condition