Effect of Sepiolite Application on Growth and Nutrient Uptake of Pistachio Seedings in the Presence of Silicate Solubilizing Bacteria under Drought Stress

The present study aimed to investigate the efficiency of silicate solubilizing bacteria in the release of elements of sepiolite. The greenhouse test was performed as factorial with completely randomized design with three repetitions. This experiment consisted of three bacterial strains (B7, B8, and D1) and pistachio (two cultivars Badami Riz Zarand and Qazvini) and four drought levels (including 90% (control), 75%, 60% and 45% of FC). The seedlings were fed with Hoagland's magnesium-free nutrient solution over a five-month growth period. The vegetative and biochemical traits of the seedlings were studied. The results showed that at the highest level of drought stress, application of strains B1 and B2 increased the rate of root Si uptake in Qazvini seedlings by 77% and 97%, respectively, and in seedlings of Badami Riz Zarand by an average of 2.75 times compared to non-drought stress conditions. Application of B7 strain increased Mg uptake in Qazvini seedlings from 6.91 mg per pot under non-drought stress conditions to 13.9 mg per pot at the highest level of drought stress. In Badami Riz Zarand, the application of the mentioned strain increased the uptake of Mg in the shoot at three stress levels of 75%, 60% and 45% of the field capacity by 74%, 67% and 66%, respectively, compared to non-drought stress conditions. Presence of these bacterial strains in symbiosis with plants will have a significant effect on the release of elements from minerals and its absorption by the plant and thus improve plant nutrition and change the mineral structure.