User blog comment:JmLyan/Lindira, the Lane Monitor/@comment-5710639-20130419170440/@comment-7481207-20130419185424

It works as it says: Her abilities change to match the type of the marked lane while she is inside it. So if she marks the mid lane with Power, her Q, W, E and Ult becomes the "Power" version of those abilities, so they would be: Power Wave, Proximity Blast, Acceleration Burst and Decemation respectively. Since her abilities change when in a marked lane, she cannot mark another lane or change its type while in it.