Seed Priming by Cyanobacteria (Spirulina platensis) and Salep Gum Enhances Tolerance of Maize Plant Against Cadmium Toxicity

Cadmium (Cd) is considered as a hazard for plant growth and human health. In the current study, the beneficial effects of maize (Zea mays L.) seed priming with salep gum (SG), Spirulina platensis (SP) and combination of SG and SP on seed germination, plant growth, photosynthesis performance, and Cd uptake and translocation factor were investigated on plants exposed to Cd toxicity (200 mg CdCl2 per kg of culture medium). Seed priming either by SG or SG + SP accelerated seed germination irrespective of Cd application. Improvement of plant growth due to seed priming by SP was observed in Cd-contaminated soil. SP caused Cd depletion in the shoots of the Cd-exposed plants. Cd translocation from root to shoot was significantly restricted in seed-primed plants after 12 days of sowing. Seed priming by SP improved photosynthetic electron flows and increased non-photochemical quenching in Cd-exposed maize plants. In conclusion, due to positive effects of seed priming (particularly by SP) on growth, photosynthetic capacity, and Cd accumulation and translocation, it can be effectively used to enhance plant capacity to cope with Cd toxicity in contaminated soils.