Emission doesn't reflect on Image texture

I’m trying to have refletion on a plane with an image texture. The emission object has the following nodes, because I want to make it a bit blury. It works here :

In a more complex project, with a hdr background and two area lamp, I made a particle trail of the emission object above. Basically I just wanted to make a bright particle trail to enlight the plane.

The background and area lamps are very weak, so the reflection of the light should be visible on the plane. It may be too weak ? Also, I’m worried as there is a lot of noise…

Once again I beg your help and thank you in advance.

cycles has problems to emit light from small particles

might improve using some composite emis blur nodes

but not that easy to do with very small particles

happy cl

I see, thank you for the information.
One other problem I found is that my scene is really small, and size has apparently importance in cycles render.