zsh problem: exporting a function within a bash script for parallel to use

[John]

Here is a simplified bash script.  The goal is to get parallel to run the 
'work' function from within the script.  Per the man page, one needs to `export 
-f FUNCTION` for this functionality, but I get the following error when I try 
running it from zsh.  If I run it from a bash shell, everything works as 
expected.

% ./test target
zsh:1: command not found: work


###BEGIN SCRIPT

#!/bin/bash
word="$1"

export word

work() {
  tar zcf $word.tar.gz $word
}

export -f work
echo $word | parallel work

###END SCRIPT