Odd Shading on meshes in game

Hi. Regarding the section where one half is dark and the other isn't, if you look at the UV layout you'll see that the UV islands corresponding to that section are split. Studio will split a mesh wherever the UV island edges exist, so it's better if you have a whole UV island and not one split in half.

* Select the top faces of the petal with the split UVs, M > by distance (this removes doubles)
* U > unwrap. Move the new UV island to a different section of the diffuse. You'll need to adjust the size and shape somewhat.
* Select the faces on the opposite side of the petal and do the same.

OR

* Delete the top and undersides of the split petal.
* Select one of the intact petals.
* Shift + D to duplicate it. The UV island will automatically be placed where you want it.
* In the 3D window, move the duplicated petal to where the split petal used to be.
* Do the same for the other side.

As for the other dark petal I couldn't see anything wrong with the mesh, nor could I see a problem with your textures. Take a look at Mauvemorn's post here, this page, and this page One of them may solve your issue.