The results of the current study are partially in agreement with thos published by GARCIA Sooo et al. (1991), who reported that the addition of high concentrations of CuSO x 5H,0(0.1 to 6.0 mg dma) to culture medium increased the organagenic response of explants in melon. Only the concentra tion of 6.0 mg Cuso. x 6H o dm a in the MS medium negatively influenced the biometric features of Dendrobium kingianum Bidwill, ie, number of shoots, number and length of roots, and fresh weight of plants As in many other plants, differential Cu transport may antagonistically affect the uptake and accumulation of other essential inorganic nutrients(HUNTER, VERGIANO 1963). In the present study, an increase in the copper accumulation in both shoots and roots was asscciated with an increase in the external cu level. An increased copper content in the M8 medium led to a slight decrease in Zn and Ca accumulation and an increase in Fe accumula tion in these organs. The copper and zinc accumulation in roots was about 1.6-2 times higher than in shoats, but that of iron waa 3-3.7 times highe JANKowsKI et al. (2014) also reported that the copper and zinc accumulation in ailseed rape roats was higher than in its straw Our findings further showed that the calcium accumulation in roots wa only 12% higher than in s Calcium is an essential macronutrient for plants, for example it plays an important role in intercellular signaling, sto matal regulation and cell wall stabilization wHITE, BROADLEy 2003). Zinc is an essential minor element, which plays many functional, regulatory and structural roles in many enzymes. This element is also important for auxin production, carbohydrate and protein metabolism, protection of cells against oxidative stress, photosynthetic reaction and maintenance of the membrane structure and functions(BRENNAN, BOLLAND 2006). Zn toxicity induces chloro sis in plants, either by competing with the uptake of other elements or due to reduction in the synthesis of chlorophyll because of Fe deficiency(BPOADLEN et al. 2007. DosPATLIEN 2011)