The combined use of silicon and arbuscular mycorrhizal fungus mitigate the adverse effects of drought stress on Matthiola incana

Effects of the application of potassium silicate (PS) and an arbuscular mycorrhiza fungus (AMF) (Glomus mosseae) were investigated on alleviating the impacts of drought stress on Matthiola incana in a split-split-plot experiment in two consecutive years. The main plot was assigned to drought stress at three levels of irrigation (25%, 50%, 70%, of field capacity) comparing with control (100% of field capacity) and the sub-plots were assigned to AMF at two levels (0 and 200 g of fungi in pots) and sub-sub plots were assigned to potassium silicate (PS) at three levels (0, 200, and 400 ppm). The application of PS with fungus increased colonization percentage regardless of the drought stress level. Regarding the interaction of drought stress and PS, it was revealed that the application of 400 and 200 ppm of PS elevated the contents of chlorophylls a, b, and total at all drought stress levels. Also, deficit irrigation versus the normal irrigation increased malondialdehyde (MDA) content both in non-AMF and AMF-containing treatments. The lowest catalase (CAT) and peroxidase (POX) contents were obtained from the treatment of 400 ppm of PS, while the highest were related to the treatment of 0 ppm of PS. Proline content was reduced by the application of 200 g of AMF and 400 ppm of PS at moderate and severe (25% FC) drought stress levels. In general, at moderate and severe drought stress levels, some physiological traits were improved by the foliar application of 400 ppm PS and Glomus mosseae inoculation.