anyway to control aperture in panorama mode?

You can get around this by using a stitching program outside your camera. Set your camera to manual mode thereby you control the aperture and shutter speed, and take your shots one at a time, making sure you overlap the edge of each scene by 30 percent.  Using the grid on the LCD helps with the horizonal alignment when you are taking the shots. I find that using this method you will get a better looking pana than what is produced in the camera.