Abstract: Taking wheat cultivar Bainong AK58 as test material, a field experiment was conducted to study the effects of different concentration 5-aminolevulinic acid (ALA) (0，10, 30 and 50 mg·L^-1) applied at initial heading stage on the post-anthesis dry matter accumulation and flag leaf senescence of the cultivar. Applying 10-50 mg·L^-1 of ALA benefited the dry matter accumulation, with its total amount at maturing stage being significantly higher than that of the control (0 mg·L^-1 ALA). 10-50 mg·L^-1 of ALA had no significant effects on the distribution of accumulated dry matter in leaf, stem and sheath, and grain, but increased the contribution of the dry matter to grain yield. 10-50 mg·L^-1 of ALA increased the leaf area index at milky and dough stages, but had no effects on it at flowering stage. After treated with 10-50 mg·L^-1 ALA, the leaf SPAD value and net photosynthetic rate from anthesis to milky stage were significantly higher, and the MDA content and relative electric conductivity at later grain-filling stage were lower, compared with those of the control. Applying 10-50 mg·L^-1 of ALA increased the grain number per spike, 1000-grain mass, and grain yield significantly, with the best effect when applying 30 mg·L^-1 ALA.

Key words: 5-aminolevulinic acid, winter wheat, dry matter accumulation, leaf area index, physiological characteristics, grain yield