Figure 1. External PA effects on the grain weights (A: Zhoumai 18; B: Xinong 538) and grain filling rates (C: Zhoumai 18; D: Xinong 538) in winter wheat.

S1: external application of Spd on panicles; S2: external application of Spm on panicles; P1: external application of Put on panicles; CK: external application of deionized water on panicles. Vertical bars represent ± the standard error of the mean (n = 3).