The pose is excellent as is the lighting (especially as it falls on the shoulders and fabric) and the colour treatment. But most of all the expression between photographer and muse. Zulma doesn't need to make eye contact, nor do we need a shot of your taking this image, to see the power of the relationship. I'm tempted to say congratulations to you - but really it is a congratulations to you both for having found and nurtured this bond.
BTW: Seems the PL25 does OK as a portrait lens too.
Very compelling portrait!
Nice use of light. Looks like two of them.
The stronger/closer/harsher of the two from behind reminds me of some of Clarence Bull's portraits.
This photograph has a quality that I think you'll enjoy for quite some time.