ABSTRACT
There are 16 elements essential for plant growth and development. They can be remembered by the mnemonic CHOPK(I)NS CaFe Mg B Mn CuZn MoCl, pronounced “C. Hopkin’s café managed by my cousin mocl” [Harriet B. Creighton, Department of Biological Sciences, Wellesley College, personal communication]. Iodine has not been shown to be essential for higher plant growth, but is added in parentheses to make the pronunciation clear. The typical concentration range varies with different elements in plants (Table 9.1). The first three elements in
our mnemonic make up organic compounds, which are not discussed in this chapter. The last 13 elements are the mineral elements. Nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium are considered to be macroelements. Chloride, iron, manganese, zinc, boron, copper, and molybdenum are microelements, also called trace elements [1]. Three other elements — cobalt, nickel, and vanadium — are not included among the 16 essential elements, but are discussed in this chapter because of their importance in some plants.
