Interactive effects of arsenic and chromium stresses on mineral and metal uptake in jute (Corchorus olitorius L.)

Abstract

Arsenic (As) and Chromium (Cr) toxicity often occurs concurrently in agricultural soils, which lead to a significant decline in crop growth and yield. A pot experiment was conducted to investigate the effects of As and Cr in the soil on the uptake of mineral elements as well as As and Cr in the two jute varieties differing in Cr tolerance during May to October, 2013. Here we report the effects of combined As and Cr stresses on plant biomass, photosynthesis, metal and nutrient uptake compared to As or Cr stress alone. Chromium tolerant variety, O-795, had significantly (p≤0.05) higher Cr and As levels in roots, stems and leaf tissues than Cr sensitive variety, O-9897. Roots had much higher As and Cr contents than above-ground parts. Arsenic stress reduced potassium (K+), magnesium (Mg2+), iron (Fe3+), copper (Cu2+), manganese (Mn2+) and zinc (Zn2+) contents in the roots and inhibited calcium (Ca2+), and from being translocated into shoots and leaves. Chromium stress resulted in decreased concentration of K+, Mg2+, Fe3+, Zn2+, Cu2+ and Mn2+ and increased concentrations of Ca2+ concentration in the root tissues. Furthermore, translocation of all nutrients from roots to upper parts of plants was inhibited except Ca2+. The combined stresses of low level of As (50 mg kg-1) plus each Cr treatment showed less inhibition of nutrient uptake, in both varieties when compared with each Cr stress alone, indicating that low levels As plus Cr showed beneficial effect than single stress. In contrast, high levels (100 mg kg-1) of As plus Cr showed further decrease in all nutrient concentrations except Ca2+ in all plant parts. These results suggest that the combined toxicity effect of low level As plus Cr on jute plant was lower than that of Cr or As treatment alone. Moreover, the reduction was more pronounced significantly (p≤0.05) in Cr sensitive variety O-9897.