The coexistence of mycorrhizal fungus on the Cathrantus Roseus medicinal plant under the influence of drought stress

The Cathrantus roseus plant is a shrub, perennial and medicinal plant Of the Lamiaceae family. One of the methods for improving vegetative conditions in arid and desert regions is the study of the roots colonization of plants with mycorrhizal fungi. For this purpose, the present study was conducted as a factorial based on completely randomized block design with four replications in Yazd University of Agriculture. The studied factors included 1- treatment of native mycorrhizal fungi with two levels (fungicidal and non-fungal) 2- drought stress treatments (containing 100%, 75%, 50%, 25%). After three months, the pots were degraded and morphological characteristics such as number of leaves, stem height, size of the largest root length, number of branches, fresh and dry weight of the shoot and root, root to shoot ratio, and percentage of colonization the root was measured. The results showed that, except for the root to shoot ratio, fungal treatments significantly reduced the fresh weight of the shoot, root length, and vitality (p<0.05).Increasing dry weight treatments, height, number of leaves, fresh weight of shoot, root fresh weight, dry weight of shoot, root dry weight, root length, and salinity significantly decreased (p<0.05).The results showed that this type of fungus in this study had the most impact on the plant's underground organs and that the highest amount of food and water was used for root preparation for better plant establishment. It seems that by case of the continuation of the survey to the next year with increasing root volume and colonization with mycorrhizal fungi more positive changes occur in the plant.