干旱对糜子籽粒发育过程中多酚含量及其抗氧化活性的影响OA

This experiment adopted a two-factor split-plot design.The main plot factor was water treatment,consisting of conventional irrigation(W0,supplemental irrigation of 30 mm at the jointing,heading,and filling stages)and two drought treatments(W1,supplemental irrigation of 30 mm only at the heading stage;W2,no sup-plemental irrigation throughout the whole stages).The subplot factor was variety,including the waxy genotype'Shaanmi 1'and the non-waxy genotype'Yumi 2'.The study investigated the changes in total phenolic content,total flavonoid content,1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical scavenging rate,and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)cationic(ABTS+)free radical scavenging rate during the grain formation process of broomcorn millet.The results showed that:(1)Under conventional irrigation and drought treatment at the full maturity stage,the spatial distribution of total phenol and total flavonoid contents in broomcorn millet grains consistently showed the pattern:husk＞whole grain＞millet.For'Shaanmi 1',the total phenol and total flavonoid contents in the husk were 28.70％and 42.81％higher than those in the whole grain and 258.48％and 415.37％higher than those in the millet,respectively.For'Yumi 2',the total phenol and total flavonoid contents in the husk were 36.66％and 23.11％higher than those in the whole grain and 172.40％and 323.50％higher than those in the millet,respectively.(2)The total phenol and total flavonoid contents in the whole grain and husk reached their maximum values at 34 days after flowering,measuring 3.95 mg·g-1,1.55 mg·g-1 and 5.10 mg·g-1,2.13 mg·g-1,respectively.The DPPH free radical scavenging rate and ABTS+free radical scavenging rate reached their maximum values at 14 days after flowering,measuring 65.93％,49.63％and 68.96％,78.85％,respectively.For the millet,the total phenol content,total flavonoid content,DPPH free radical scavenging rate,and ABTS+free radical scavenging rate all reached their maximum values at 14 days after flowering,measuring 3.17 mg·g-1,0.77 mg·g-1,45.71％,and 52.20％,respectively.(3)Drought stress increased the total phenol content,total fla-vonoid content,and antioxidant activity in the whole grain,husk,and millet of broomcorn millet.Under the W2 treatment,the total phenol content,total flavonoid content,DPPH free radical scavenging rate,and ABTS+free radical scavenging rate were 10.92％,16.81％,8.82％,and 3.39％higher than those under W1 and 17.16％,38.95％,21.24％,and 5.90％higher than those under W0,respectively.Overall,drought facilitates the production and accumulation of polyphenols in broomcorn millet grains and enhances their antioxidant activity.The antioxidant activity of the whole grain,husk,and millet is stronger during the early stages of development.