After-ripening And Physiological Changes In Seed Of Paris Polyphylla Smith Var. Chinesis (Franch.) Hara During The Stratification Period

As a high-frequency and well curative traditional Chinese medicine, Paris polyphylla Smith var. chinensis has been an endangered species because of the gap between production and consumption. Regard of the sharp decline of wild Paris polyphylla Smith var. chinensis, it is necessary to promote the artificial cultivation. Paris polyphylla Smith var. chinensis could be reproduced themselves by their rhizomes or seeds. It should be noted that the later method has significant advantages, such as more higher reproduction coefficient and hazard-free treatment to medical parts. Unfortunately, because of the lack of knowledge about the seeds’ dormancy mechanism, the seeds of Paris polyphylla Smith var. chinensis are still difficult to germinate without the aid of stratifcation treatment. In this study, the dormancy physiological and biochemical mechanism of seeds of paris polyphylla Smith var. chinensis were explored from four aspects, such as morphological characteristics of seeds’ embryo, the dynamic change of bioactivity of five enzymes, the variation of allelopathic effects of seeds, and the content of four endogenous hormones. Some key results were presented below.(1) The results indicated that Paris seeds embryo grow quickly after 40d in warm-stratification (18+1℃), at the meantime the metabolic activity was significantly strengthened. These facts showed that Paris seeds have turned into physiological after-ripening process. After 60-80d, the morphological embryo after-ripping process basically completed, and the followed cold-stratification (4+1℃) further urged Paris seed finish physiological after-ripening.(2) IAA and ABA did not detected during the whole stratification, maybe because of the extremely low content. The content of GA fluctuated in a relatively narrow span without any significant changes. They are not likely to regulate and control the dormancy of Paris seeds. However, the content of Z rose in the 0-60d and then fall down in the 60-120 d. The result showed that Z most likely to be involved Paris seed physiological regulation.(3) The content of allelopathic chemicals were keeping increasing during the former 60 d of the process of stratification, then started to drop in the later 60 d of stratification. In the whole process of stratification, the aqueous extract of seeds of paris polyphylla Smith var. chinensis were always having the allelopathic effects on cabbage’s seedlings, with the main inhibiting effects on its growth of the radicles.(4) After 40d, the activity of MDH decreased and G-6-PDH increased significantly. This showed that the main respiratory pathway of seed have changed from TCA to PPP, which is beneficial for breaking seed dormancy. In the whole period of stratification process, the activity variation of SOD and CAT was insignificantly and the activity of POD was enhanced significantly after shifting the seed in cold stratification process. This showed that SOD、CAT have no direct effects on breaking Paris seed dormancy but keeping the seed vigor, while the POD maybe involved in the process of Paris seed dormancy breaking.(5) Muti-evidence showed that,40-60 d were the critical period for Paris seeds dormancy. During the period, the morphological after-ripening of seeds finished, the content of Z and allelochemical reached the summit, the main respiratory pathway changed.