Effect of Glomous mosseae inoculation on growth and flower quality of zinnia bedding plants under different drought levels

The application and inoculation of substrate medium with arbuscular mycorrhizal fungi (AMF), in relation to increasing abiotic stresses such as drought and salinity, in particular in drought climates, need more attention. This study was arranged in a factorial design with three drought levels (40, 70 and 100% of field capacity (FC)) and three inoculation levels (0, 2.5 and 5% W/W). Recordings were made of morpho-physiological parameters (plant height, water use efficiency, phosphorus uptake, flower diameter, total chlorophyll and lipid peroxidation) of Zinnia elegance 'Dreamland Red', based on a completely randomized design with three replicates. Results showed the significant and positive effects of AMF inoculation on all mentioned parameters under different irrigation regimes. Compared with AMF treated plants, increasing drought levels led to decreasing plant height, water use efficiency, phosphorus uptake, flower diameter and chlorophyll content. The maximum flower diameter as an important flower quality factor was observed in 70% FC and 5% inoculation level, which was about 2.5 times higher than the 40%FC and non-inoculated plants. The highest total chlorophyll content was observed in 100% FC and 2.5% inoculation levels. Also, compared with AMF treated plants, the highest lipid peroxidation level was shown in the lowest irrigation level (40% FC) without inoculation treatment. The results suggest that AMF symbiosis with zinnia, in addition to drought stress mitigation, led to improvement of flower quality.