Table 3. Composition of in vitro buffer solution

Item g/L
Buffer solution A
 KH2PO4 10.0
 MgSO4·7H2O 0.5
 NaCl 0.5
 CaCl2·2H2O 0.1
 Urea (regent grade) 0.5
Buffer solution B
 Na2CO3 15.0
 Na2S·9H2O 1.0