Ken,

Many thanks for posting a reply with complete working code. Since posting I managed to find a work-around by adding a data string to the node entry in the tree, and then pulling the info later:

$string='Match';
#
#define Itemstyles
#
$tree1_match_style = $tree1->ItemStyle('text', -foreground=>'green');
$tree2_match_style = $tree1->ItemStyle('text', -foreground=>'green');

#
#add node to tree1 and tree2
#
$tree1->add($indent0_line,-text=> $indent0_line,-itemtype=>'text');
$tree2->add($indent0_line,-text=> $indent0_line,-itemtype=>'text');
 
#
#add style to node entry 
#
$tree1->entryconfigure($indent0_line,-style=>$tree1_match_style);
#
#add data to node entry 
#
$tree1->entryconfigure($indent0_line, -data =>$string);

#
#retrieve data from node
#
my $style_data=$tree1->infoData($indent0_line);
#
#retrieve style from node
#
my $wanted_style = $tree1->entrycget($indent0_line, q{-style});

#
#print retrieved data and style
#
print "Tree1 style[$style_data]\n";
print "Tree1 wanted style[$wanted_style]\n";

#
#configure style of node in tree2
#
if ($style_data eq $string)
{   $tree2->entryconfigure($indent0_line,-style=>$tree2_match_style);
}
[download]

When run the output is as follows:

Tree1 style[Match]
Tree1 wanted style[Tk::ItemStyle=HASH(0x21dd6d4)]
[download]

However I've just used the pertinent lines from your post/code to shorten all the above to the follows, and it works a treat:

$string='Match';
#
#define Itemstyles
#
$tree1_match_style = $tree1->ItemStyle('text', -foreground=>'green');
$tree2_match_style = $tree1->ItemStyle('text', -foreground=>'green');

#
#add node to tree1 and tree2
#
$tree1->add($indent0_line,-text=> $indent0_line,-itemtype=>'text');
$tree2->add($indent0_line,-text=> $indent0_line,-itemtype=>'text');
 
#
#add style to node entry 
#
$tree1->entryconfigure($indent0_line,-style=>$tree1_match_style);
#
#


#retrieve style from node
#
my $wanted_style = $tree1->entrycget($indent0_line, q{-style});

#
#configure tree2 node  with retrieved style from tree1 node
#
$tree2->entryconfigure($indent0_line,-style=>$wanted_style);
[download]

The pertinent line in all this is the entrycget, and despite all my previous searching I was not aware you could retrieve the style of an item (hence my posting!)

Again, many thanks for taking the time and effort to reply and post a working script.