4572
According to the concept of BLM , the present results revealed that the amelioration effects of Mg on Cu toxicity and accumulation in roots could arise from competition between Mg ( 2 + ) and Cu ( 2 + ) on the binding sites ( i . e . , the biotic ligands ) .
 Chemical: Mg; Chemical: Cu; Chemical: Mg ( 2 + ); Chemical: Cu ( 2 + )
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Mg; Chemical: Cu; Chemical: Mg ( 2 + ); Chemical: Cu ( 2 + )