Regulation of paclobutrazol and N fertilizer on physiological function of winter wheat leaves

In order to cultivate strong winter wheat spout in the jointing stage, settle the contradiction between the excessive vigor growth resulted form the application of N fertilizer and strengthing the lodging-resist ability of winter wheat in the later period of winter wheat, field experiment was conducted to study the physiological effects of paclobutrazol at different N-application levels on winter wheat leaves. Two-factor-overlapping design was adapted in this study. The results indicated that, compared with the control, the application of paclobutrazol and N not only increased wheat leaf area, but also improved significantly chlorophyll content and photosynthesis rate. Meanwhile, the SOD activities of leaf were increased, and stress resistance was strengthened. The recommended application rates of N and paclobutrazol of winter wheat at the jointing stage were N 104.2–156.3kg/ha and 1.13–1.50 kg/ha，respectively in the lince brown soil.