【Objectives】Potassium( K) is essential for oilseed rape( Brassica napus L.),insufficient supply will decline the leaf photosynthetic capacity,as well as seed yield. The present study was conducted to compare the response of different leaves( namely long-stalk leaf,short-stalk leaf and no-stalk leaf) to K deficiency at stem elongation stage under field conditions. Additionally,we attempted to find out the dominant limitations and reveal the underlying mechanisms due to K deficiency which restrained the leaf ...