| Oldenlandia diffusa (Willd.) Roxb (Rubiaceae) is an important medicinal plant. Its dried aerial part was commonly used as Chinese medicine, with clearing heat and detoxicating, inducing diuresis and reducing edema effects, indications of sore throat, damp-heat and jaundice, dysuria, swollen sore and furuncle carbuncle, acute and chronic cholecystitis, urinary tract infections, snakebite and other diseases, and has general clinical applications. It has been recorded in Chinese Pharmacopoeia (2010edition) as a medicine materials in Appendix.Excellent germplasm is critical to Chinese medicinal materials. Current paper focused on O.diffusa seed testing methods, seed quality classification criteria, storage methods, and priming technology to improve seed vigor. The results are as follows:1. According to the related seed testing regulations, the seed quality of O. diffusa from different producing areas was measured.’Winnowing was the optimum cleaning methods for seed of O. diffusa. The seed weight should be determined based on1000seeds. The moisture was determined after drying at105℃for2h. And germination temperature was25℃with8000lx illumination. Sand bed covered with a piece of pape was optimum for seed germination. Additionally, conductimetric method was favorable for determination for seed vigor.2. Thirty batches of O. diffusa seeds from different provenances with different collecting time were selected. And the seed germination percentage, seed purity, weight per1000seeds, moisture content, seed viability were determined and analyzed with SPSS11.0software. Seed germination percentage was selected as the main index for classification, while seed purity, weight per1000seeds and moisture content could be used as references.The quality classification criteria of O. diffusa seeds has been initially established. The first class was characterized by germination rate≥44%, purity≥99%, weight per1000seeds≥10.84mg, and moisture content≤7.8%. The second class was characterized by germination rate ranged from32%to44%, purity ranged from96%to99%, weight per1000seeds ranged from10.76to10.84mg, and moisture content ranged from7.8%to8.5%. And The third class was characterized by germination rate≤32%, purity≤96%, weight per1000seeds≤10.76mg, and moisture≥8.5%.3. Four kinds of storage methods including airproof storage at normal temperature,-20℃storage, airtight storage at normal temperature and4℃storage were selected, and germination rate, Germinability and Initial germination time were measured after storing for90,180, and270days. The germination rate of O. diffusa seeds was reduced with the extension of storage time. Storage under both4℃and-20℃conditions can extend O. diffusa seeds life, and O. diffusa seeds was recommended to be stored at4℃according to germination rate, germinability and initial time of germination.4. Uniform design was used to optimize the concentration and priming time of three priming materials (PEG, KNO3, and GA3). Different concentrations of polyethylene glycol (PEG) was used to simulate drought stress. PEG concentration significantly affected the germination rate, germination index and vigor index. Seed priming treatment with366mg·L-1GA3for1h resulted in significant increase in germination rate, germination index, vigor, root length, plant height and biomass of O. diffusa seeds under drought stress (15%PEG), while seed priming with3.0%KNO3for1h showed little effect on germination and growth of O. diffusa seeds under drought stress. The results suggested that seed priming treatment with appropriate GA3concentration and priming time could enhance seed germination and drought resistance of O. diffusa in seedling stage. |
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