how to set the datatype for text in stored procedure

[shaddf]

what data type can I use to define a text field input parameter in the stored procedure below;in the data base  table it is defined as:

 comment text,

 and in the stored procedure how can I define it:

CREATE PROCEDURE sp_ne comm(in in_Nature_id  varchar(256)/text)
MODIFIES SQL DATA
BEGIN

      insert into me(comment)values(in_Nature_id ie vvvv uygliuyiuyo......>256 characters);
END