Objective: To explore the difference of the shapes of fruits and germination characters of seeds of Rheum palmatum, R. tanguticum and R. officinale.
Method: The seeds of three Rheum species including wild and cultivation one were collected from different regions. Character of the fruits appearance were observed. The purification, weights per thousand seeds, content of moisture, seed vigor and different germination rates of Radix et Rhizoma Rhei were measured. The germination rates of the seeds of R. palmatum were determined under different temperature and hormone treatment .
Result: It was markedly variant in shapes of the fruits, rates of germination and all quality characters of the three category of Radix et Rhizoma Rhei. As reported, the size of the fruit and seed and weights per thousand seeds of R. officinale was the biggest. The seed vigor and germination rate of R. palmatum caltivated in Ming county of Gangsu were 95.7% and 94% respectively. The rate of seed vigor was closely correlated with the rate of germination for other species. Results indicated that temperature had some effects on the germination, and there were obvious difference in the active effect of gibberellin, kinetin and 6-benzyl aminopurine on the germination of the seed. Our experimental results showed that the kinetin concentration of 50 x 10(-6) g x L(-1) had the most active effect, and its rates of germination increase 18 percent than the control one.
Conclusion: Significant differences exist in the shapes of fruits, rates of germination of the seeds of Rheum, which are affected by the factors of temperatures and hormones. The result of this study provides scientific evidences for identify, growth and cultivation of Rheum.