Improving effects of mycorrhizal symbiosis on sorghum bicolor under four levels of drought stress

Abstract

This study was conducted to determination the symbiotic effects of arbuscular mycorrhizal (AM) fungi on the shoot and root characteristics and mycorrhiza influence on relationships between minerals (phosphorus and Nitrogen) acquisition and yield components under drought stress in Sorghum bicolor. A pot experiment was carried out in Shiraz, Iran in 2010 growing season. The experiment was conducted using split-plot arrangements in a randomized complete block design (RCBD) with three replications. Treatments were based on drought stress in four levels and mycorrhiza infection stages consisted of mycorrhiza inoculated (M1) and non-mycorrhiza (M0). The results showed that the drought stress had significant influences on root colonization percent, shoot dry matter weight, plant height, leaf area, root dry matter weight, root/shoot ratio, root length and root wet weight. It seems to be that the mycorrhiza had visibly increased the biomass of sorghum by impacts on the root characteristics, such as: root weight, root length, and root/shoot ratio. The cluster analysis indicated that shoot dry matter weight was correlated with root dry matter weight in non-mycorrhizal condition. Plant height and root length traits were also correlated with leaf area and root wet weight. While, these relations changed in mycorrhizal condition and plant height, leaf area, root wet weight and root length were correlated with root colonization percent. Also cluster analysis indicated the great improvement in relations between morphological traits and nutrients absorption and yield components by effects of mycorrhizal inoculation.