Cadmium accumulation by muskmelon (Cucumis melo L.) in saline and contaminated organic growing media

摘要

A greenhouse experiment was carried out to investigate the response of muskmelon (Cucumis melo L.) grown in peat at increasing root zone salinity and contamination of growing media with Cd. The effect of a factorial combination of four NaCl salinity levels (2 as control, 4, 6, and 8dS/m) and three levels of Cd in peat (0.3 as control, 5 and 10mg/kg) on mineral accumulation and distribution in plant as well as yield of muskmelon was assessed. Salt stress, indicated by reduced leaf dry matter content (4% 34%) and marketable yield (up to 50%), was accompanied by significantly increased Na and Cl accumulation as well as decreased K concentration in leaves and fruits. Cadmium accumulation in leaves increased with increasing salinity 25 days after commencement of the salinity treatment;however, after 50 days of salinity treatment, increased Cd accumulation in leaves occurred only at the highest salinity (8dS/m). Cadmium accumulation in muskmelon fruits was not influenced by salinity. The order of Cd concentrations in tissues [in mg/kg: leaves (9. 1- 17)＞peel (0. 4-0. 6)＞pulp (0.3-0.4)] suggests that muskmelon has low capacity (i) to transport Cd into fruits, and/or (ii) to translocate Cd from leaves to fruits. The hypothesis that NaCl salinity enhances Cd uptake was not supported for muskmelon.