Abstract: Using Yangmai 11 as the material, we investigated the impacts of asymmetric warming on the key enzyme activities in starch synthesis in winter-wheat superior and inferior grains based on field study with FATI (Free Air Temperature Increased) facility. The results showed that the activities of sucrose synthase (SS), ADP-glucose pyrophosphorylase (AGPase), and starch branching enzyme(SBE) were higher in superior grains than in inferior grains, and also higher in the daytime than at night. In the control during the grain filling stage, the average activities of SS, AGPase, and SBE were 72.9%, 111.4%, and 7.8% higher in superior grains than in inferior grains. In superior grains, the SS activities in all-day warming, daytime warming and nighttime warming treatments were 8.4–31.2% higher than those in the ambient control in the daytime, and 11.1–20.3% higher than those in the control at night. In inferior grains, the increased percentages were 9.7–20.3% in the daytime and 6.1–32.0% at night. In inferior grains, the AGPase activities were elevated significantly compared to the control with 54.2–124.4% in the daytime and 20.7–99.3% at night. The SBE activities were also higher in the warming treatments than in the control with the increase of 3.9–12.1% in the daytime and 1.0–7.6% at night. Besides, the correlations existed between the activities of AGPase and SBE and the 1000-grain weight were positive and significant. This result indicated that elevation of AGPase and SBE activities plays an important role in the enhancement of 1000-grain weight.

Key words:

Asymmetric warming')">font-size: 9pt" lang="EN-US">Asymmetric warming, Winter wheat, Superior grain, Inferior grain, Key enzymes for starch synthesis, 1000-grain weight