Geographic Variation Of Morphology And Physiology Characteristics And Seed Germination Physiology Of Sinopodophyllum Hexandrum

Sinopodophyllum hexandrum is an endangered species, which is resulted from human abusing exploration due to its commercial application on synthesis of precursor of anticancerogen. Here, for the purpose of conservation biology, this paper mainly researches its morphological characteristic, seed characteristic, photosynthetic trait on the geographical variation and its seed germination.1. Diversity is existed in both between and among populations in phenotype of S. hexandrum. Differention between populations is more than that of member among population, which indicated a varying variation on the level of species. However, differential randomness on whole is shown on its morphological characteristic, which indicated that its morphological variations result from environment factors and genetic factors in itself, but both factors are not real reason of geo-environmental regularity variation and which also shows a young species.2. S. hexandrum can produced greater seed and seed number per fruit increases with increasing latitude, while per seed weight decreased with the increasing the latitude and these two traits in different populations had a significant difference (P <0.05). That is different life history strategy of choice results in S. hexandru in different habitats. The correlation between the number of seeds per fruit species and single-grain weight shows a weak negative correlation (r =- 0.1659, p = 0.134). All in all, for S. hexandrum, the larger fruit contained smaller seeds smaller, or vice versa.3. Seed viability of S. hexandrum and germination rate is high. Although the effects of external environmental factors on the seeds catalase (CAT), superoxide dismutase (SOD), dehydrogenases and amylase activities showed inhibition or enhancement activity; however, little influence was taken place on its seeds germination. Dense seed coat, pericarp contents, and embryo development are not main reason of seed dormancy. Therefore, further research is performed to find the real reason of its seed dormancy.4. S. hexandrum is a shade-tolerant species between sun plant and shade plant, but their shade-tolerance is different among individuals from each region: S. hexandrum from the middle and the south areas are supposed to be suitable to grow in shady areas, the northern individuals are more adaptive to grow in the better light conditions. Farther more, the response course to photon flux density (PFD) and CO₂ concentration of S. hexandrum from different distribution areas exhibited biggish difference, all the photosynthetic parameters were different distinctly. These indicate that S. hexandrum growing in different habitat have formed adaptive change not only in their morphology but also photosynthetic physiology, and these variations are caused by genetic divergence among populations.5. To our best knowledge, the reason resulted in the endangered population are listed as follows: (1) over-exploration activity and environmental degradation; (2) animal's predatory behavior; (3) the longer vegetative growth stage; (4) slowly seed germination; (6) serious habitat fragmentation.