GRANT SELECT ON table TO $1

I'm a newbie of PostgreSQL, I have a function like this:

CREATE OR REPLACE FUNCTION func(TEXT)
RETURNS integer
AS $$
BEGIN
  GRANT SELECT ON table1 TO $1;
END;
$$
LANGUAGE 'plpgsql';

and I get something like this:

ERROR:  error de sintaxis en o cerca de «$1» at character 31
QUERY:  GRANT SELECT ON table1 TO  $1
CONTEXT:  SQL statement in PL/PgSQL function "func" near line 7
LINEA 1: GRANT SELECT ON table1 TO  $1

I think that the problem is the data type (TEXT) but I can't find the solution.

Can somebody help me with that problem please.

Thanks.

Sorry for my English.