Positively closed classes of three-valued logic generated by one-place functions

We consider the positive closure operator on the set $P_3$ of functions of three-valued logic. It is shown that in $P_3$ there are exactly 51 positively closed classes positively generated by one-place functions, 26 of these classes are generated by a single one-place function (including one of the positively precomplete in $P_3$ classes), and 25 classes are generated by two functions (including the class $P_3$ and the remaining 9 positively precomplete classes).