Until Google launches an API for the Google+ Comments feature, you can use the code from Blogger. Browsing the Net found a way to embed Google+ Comments on any website or blog. Here's the code you could use:

<script src="https://apis.google.com/js/plusone.js">
</script>
<div class="g-comments"
    data-href="[URL]"
    data-width="642"
    data-first_party_property="BLOGGER"
    data-view_type="FILTERED_POSTMOD">
</div>

Replace [URL] with the address of your page. If you enter the URL of a different page, Google shows some Google+ posts that link to that page and all the comments for that page. For example, if you enter the URL of this blog post, you'll see all the comments and Google+ messages from this page and you can also add a new comment.

It's important to keep in mind that this is an unofficial way to add Google+ Comments and Google can always change the code or remove some features.

{ Thanks, Jerzy. }