A practicable method for zinc enrichment in lettuce leaves by the endophyte fungus Piriformospora indica under increasing zinc supply

Zinc (Zn) deficiency is well-documented public health issue and a significant factor hampering to crop production. There is a close overlap between soil deficiency and human deficiency of Zn, indicating a need for increasing Zn content in crops and vegetables. In this study, the effects of endophytic fungus Piriformospora indica and Zn treatment on growth parameters, chlorophyll amounts, and Zn and some other micronutrient concentrations in Lactuca sativa cv. Siyahoo plants were investigated. The experiment was carried out including two treatments (P. indica inoculation and non-inoculation), each having four Zn concentrations (0, 2.5, 5 and 10 mg/l Zn added to full-strength Hoagland solution) in a sand culture substrate. By increasing Zn concentration in sand substrate, growth parameters, chlorophyll content and leaf Zn concentration were significantly increased from 34.1 to 185.1 μg/g DW, whereas leaf iron (Fe) concentration was decreased. Significant increase in various parameters including growth, chlorophyll content and leaf Zn concentrations (7.6 fold) were observed in plants inoculated with P. indica under supplemented concentration of 10 mg/l Zn. Results from this study indicate that P. indica inoculation with Zn supplementation can help in Zn enrichment in lettuce plants.