Fig. 4

Exogenous ABA priming improved yield component indices in rice under heat stress. The rice plants were sprayed with distilled water, 50 μM ABA or 10 μM fluridone (FLU) at the 5th d after initial heading stage (AIH) or 12th d after initial heading stage, and then subjected to unstressed or heat stress conditions at 8–14 days after initial heading (AIH) stage or 15–21 days after initial heading stage, respectively. (A) Panicle number (PN), (B) spikelets per panicle (SP), (C) filled spikelets (FS), (D) empty spikelets (ES), (E) percentage of filled spikelets (PFS, %), and (F) 1000-grain weight (TGW, g) were measured at the mature stage. Values are means ± SDs, n = 3. Different letters on the column represent significant differences (P < 0.05) between different treatments based on Duncan’s test