Some effects of nickel toxicity on rye grass

Summary

Rye grass (Lolium perenne, cv.S-23) was grown for 4 weeks in a non-calcareous Seaton loam soil with varying amounts of Ni as NiSO₄. The purpose of this investigation was to study the Ni toxicity and the relationship of Ni with other essential elements. Nickel depressed shoot yield at all levels except at the lowest levelviz 30 μg Ni/g soil. Nickel concentration of 50 μg/g in shoots did not reduce the dry matter production in rye grass although slight chlorosis did appear at this level. The Ni and Fe concentration of the shoots increased and that of Mn and Zn decreased with increasing rates of Ni application. Uptake of Mn and Zn decreased at all level of Ni. But Fe uptake showed a slight increase at the first two levels and a profound depression at the subsequent levels. The pattern of Ni uptake is different, being highest at the middle level and decreasing on both sides which showed that the increase of Ni concentration of shoots is not proportional to the reduction in the yield. The Ni−Fe ratio rather than Ni and Fe concentration in plants has shown better relationship with the toxic effects of Ni. The implications of Ni phytotoxicity are discussed with particular reference to serpentine soils.