Objective: To study grain filling characteristics of triennium-growth Angelica sinensis in order to provide theoretic evidence for determining the adapted harvesting time for seeds.
Methods: 1000-grain fresh and dry weight, 100-grain volume, grain length, width and thickness in different spikes which were measured every day from the 8th day afte the head spike bloomed and finally estimated by Logistic equation.
Results: It was the peak filling time when the grain water decreased most rapidly. The grain filling speed, intensity, dry matter accumulation in head spike were all higher than those in the second spike, which resulted in early peak. The seeds in the head spike had advantages in grain filling and their adapted harvesting time should be the 13th day after blooming, when there were 86.2% of dry the maximum matter accumulation and 68.8% as water content in seeds. However, the adapted harvesting time for the seeds in the second spike should be the 14th day after the first spike bloomed, when there were 82.0% of the maximum dry matter accumulation and 72.2% as water content.
Conclusion: According with the Logistic equation, the grains filling in different spikes had the same duration but differed in the intersity. We should harvest the whole plant seeds at a time, and away the head and below weak spikes before blooming.