Surely it's not just portato? Can't you hear the grating, "sawing" timbre? It's seems a very different sound to mere portato: http://www.youtube.com/watch?v=whXj4-60SR0.
If you listen to it at 1;19-1:30, there's definitely something different to normal playing - it seems more "wispy" or "airy" (a similar "sawing" sound to before). Sorry I can't describe it any better! My headphones are quite sensitive, maybe they're just picking the sound up more clearly? All I know is that it sounds different - maybe the violinist is using a different part of the bow/etc?