INTRODUCTION: The seed maturity has a significant impact on germination rate and seedling growth of Angelica sinensis. RATIONALE: Here, the changes in morphological structures, 1000-seed weight, germination rate and physiological indicators of A. sinensis seeds at different maturity stages were examined. RESULTS: The seed maturity of A. sinensis was divided into 4 stages including: S1 (milk stage), S2 (wax stage), S3 (ripe stage), and S4 (straw stage) based on seed morphologies and anatomical structures at different maturity stages. The color of seeds transited from green (S1) through greenish-yellow (S2) to yellowish-brown (S3) and then brown (S4). Water content of seeds significantly decreased from S1 to S4, 1000-seed fresh weight (2.16 g) and 1000-seed dry weight (1.59 g) reached the maximum at S3 while significantly decreased at S4. The seed germination rate showed S3＞S4＞S2＞S1 at different germination stages, with germination rate increasing from 30.00% to 71.67% after sowing 10 to 30 d for seeds of S3, meanwhile, seedlings of S3 exhibited stronger growth vigor after germination than other mature stages. The contents of soluble sugar, starch, amino acid and IAA significantly decreased from S1 to S4, the protein content reached the maximum at S3, as well as the ABA content significantly decreased from S1 to S2 while significantly increased at S4. Correlation analysis found that there was a significant correlation of germination rate with IAA content (P<0.01). RT-qPCR detection found that there were significant changes in expression levels of genes involved in IAA and ABA biosynthesis in seeds at different maturity stages. CONCLUSION: Thereafter, the ripe stage is suitable for harvesting the seeds of A. sinensis, with the maximum 1000-seed weight and the highest germination rate.
Bao et al. (Wed,) studied this question.