بررسی تاثیر تنش نیکل و همزیستی اندوفایت نئوتیفودیوم بر برخی شاخص های رشد و جذب نیکل در گیاه Lolium perenne

Lolium perenne has symbiosis relationships with an important group of endophytes genus Neotyphodium. Agronomic traits of this plant and its resistance to biotic and abiotic stresses are affected by Neotyphodium spp., resulting to changes in its physiology and morphology. Effect of Nickel and endophyte symbiosis on growth parameters and nickel uptake in two different natural populations are investigated in this study. Each population consisted of two groups of plant (E+ and E- with or without endophyte). Treatments consisted of 0, 30, 90 and 180 mg Ni kg 1- soil), and growth parameters including root and shoot wet, dry weight and length, tiller number, and nickel uptake in root and shoot were evaluated after 3 months from treatment. After 3 months from treated plants, significant decrease in root and shoot biomass of E+ and E- plants was observed in 180 treatment and endophyte infection decreased the biomass plants. However, endophyte infection significantly improved the tillering ability of host ryegrass. Also, a significant increase in the Ni concentration of root and shoot was observed under Ni stress and the Ni concentration of E+ plants was 12.7% and 88.7% higher in root and shoot, respectively, than in E- plants. Results indicated decreases in root and shoot wet and dry weights were decreased in concentration 180 mg.kg-1 treatments, and root length in concentration 30 mg.kg-1. Greatest number of tillers observed in population 1 in 30 mg.kg-1 treatment. Nickel uptake was significantly increased in roots and shoots of both populations when soil Ni was increased. Nickel uptake of root and shoot in two populations of L. perenne plants was decreases in presence of with endophytes (E+ plants) which is considered as an important factor towards decrease in negative effects of this element. Population 1 with more shoot tiller and nickel uptake under stress conditions could be introduced as the suitable population to be cultivated in stress conditions.