The effect of arbuscular mycorrhizal fungus on photosynthetic pigments and growth parameters of Valeriana Officinalis L. under water-deficit stress

Water deficit is one of the most common abiotic stresses worldwide, including Iran that limits plant growth and production by disrupting photosynthetic processes. One of the biological solutions for improving tolerance of plants under stress is the application of biofertilizers containing beneficial soil microorganisms, such as arbuscular mycorrhizal fungi (AMF). This research aimed to evaluate the effect of inoculation with Funneliformis mosseae on valerian growth parameters and chlorophyll content under drought stress conditions during ۲۰۱۹ and ۲۰۲۰ in a factorial completely randomized design with four replications. Mycorrhizal and non-mycorrhizal plants were subjected to three different moisture levels (available water (AW): ۱۰۰% AW, ۷۰% AW, and ۴۰% AW) for two months. Results indicated that drought stress significantly reduced shoot and root fresh and dry weights, root length, and total dry weight at both moisture levels of ۴۰% AW and ۷۰% AW. Also, a significant decrease was observed in leaf relative water content at the moisture level of ۷۰% AW, and chlorophyll a, chlorophyll b, and total chlorophyll contents only at the moisture level of ۴۰% AW. In this study, inoculation with Funneliformis mosseae induced a significant increase in shoot and root fresh weight, root dry weight, total plant dry weight, and root/shoot dry weight ratio at both drought levels. Root length at ۷۰% AW level and shoot dry weight at ۴۰% AW level in mycorrhizal plants were significantly higher than non-mycorrhizal plants. Moreover, the contents of chlorophyll a, chlorophyll b, and total chlorophyll of AM plants at the control and ۴۰% AW moisture levels were about ۲۰ and ۵۰% significantly higher than the corresponding NM plants, respectively. The results showed that mycorrhizal inoculation of the plant could increase the photosynthetic capacity resulted in the improvement of host plant growth characteristics under drought stress.

کلیدواژه ها:

Funneliformis mosseae ، osmotic stress ، Valerian ، biomass ، chlorophyll content