Particle objects not rendered

Hi guys,

first time posting here, first of all, english is not my native language but i will try to be as much clearer as i can.

So, i’m having a little issue with my hair particle system, i’ve tried to animate a weight paint brush on my canvas to control the size and density of a bunch of grass and weeds particles. It’s works fine in the viewport, giving the illusion that the grass is growing and spreading, but when i try to render it, all the particles disappear :frowning:

I can’t figure out what’s going on and i’m pretty sure that the solution is simple… so here i am, asking for you help. :o

Thank you in advance !

Nobody can help me ? :’(