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 H(2)O(2) 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 CdCl(2) (0, 50, 100 and 200 microM) to the nutrient solution. Under high concentrations (100 and 200 microM) of CdCl(2), 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 microM CdCl(2). Anti-oxidative enzyme activities, H(2)O(2) 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 microM) concentrations of CdCl(2). There was no significant difference (P>0.05) under 0 and 50 microM CdCl(2). Endophyte infection was concluded to be of benefit to the growth and anti-oxidative mechanisms within A. inebrians under high concentrations exposures to CdCl(2). (c) 2009 Elsevier B.V. All rights reserved.