Effect of Epichloë gansuensis on Nutrient Resorption Efficiency, Metal Ion Concentrations and Nutrient Ratios of Achnatherum inebrians under Various Nitrogen Concentrations

It is well known that low N limits crop yield, but plants can rationally use nutrients to improve the plant growth at adverse environments. However, the effects of  E. gansuensis  on nutrient resorption efficiency and metal ion contents of  Achnatherum inebrians  at low N were unknown.  A. inebrians  with (E+) and without  E. gansuensis  (E-) were treated with 0.1 mM (low) N and 7.5 mM (normal) N, after 90 days, the dry weight, the contents of N, P, K, Na, Mg, Zn, Cu, Ca and Fe in senescent and green leaves, N/P/K resorption efficiency at 0.1 mM N and 7.5 mM N were assayed. We found that  E. gansuensis  enhanced the dry weight of green leaves of  A. inebrians , and increased nitrogen resorption efficiency (NRE) of host plant, and the content of N and P in green leaves at 0.1 mM N, but decreased N content in senescent leaves compared to E- plant at 0.1 mM N. The  E. gansuensis  played an important role in improving host grasses growth at low-N stress by enhancing NRE, and influencing the content of Na, Mg, Zn, Cu, Ca and Fe in senescent leaves and green leaves.