First Grow Pretty Lucky!

Hi guys, I made a post here about 2 months ago at the beginning of my grow. I started out with 8 plants, parted out only 1 male! I do have a problem of course, I have this maybe 1 month 1 week old Sensei plant that has already sexed itself but she is at a horrible growth pause in the main stem. Can someone tell me by the picture? If you can see in the middle, there is a V and will show the end nub at the top of my plant. Other than that I think shes a fine plant, but won't be able to support much bud weight.

Any clue? =\

That plant looks like it might have not had enough light at some point, but I have seen a lot worse. If you don't have a fan on it get a fan on it and it will strengthen up the stem and will increase the bud weight it can hold.