Effects of cadmium stress on growth and anti-oxidative systems in Achnatherum inebrians symbiotic with Neotyphodium gansuense

The effects of cadmium on biomass production and growth parameters of drunken horse grass (Achnatherum inebrians) over an 8-week period were determined in a controlled-environment experiment. Changes were determined for relative water content, anti-oxidative enzymes (i.e., catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX)) and for H2O2 content, as well as levels of proline, malondialdehyde (MDA), and chlorophylls “a” and “b” present within leaves infected with Neotyphodium gansuense vs. non-infected controls. Observations began 4 weeks after addition of CdCl2 (0, 50, 100 and 200 μM) to the nutrient solution. Under high concentrations (100 and 200 μM) of CdCl2, endophyte-infected plants produced more biomass and had higher values for plant height and tiller number compared to non-infected controls, but there was no significant difference (P > 0.05) under 0 and 50 μM CdCl2. Anti-oxidative enzyme activities, H2O2 concentration, and chlorophylls “a” and “b” levels increased, but proline and malondialdehyde content declined in the infected plants vs. non-infected plants under high (100 and 200 μM) concentrations of CdCl2. There was no significant difference (P > 0.05) under 0 and 50 μM CdCl2. Endophyte infection was concluded to be of benefit to the growth and anti-oxidative mechanisms within A. inebrians under high concentrations exposures to CdCl2.