Study On Conservation Biology Of The Endangered Species Kirengeshoma Palmata Yatabe

Kirengeshoma palmata Yatabe is a perennial, herbaceous species of the monotypic genus Kirengeshoma Yatabe of Hydrangeaceae endemic to China (merely at the junction of Anhui and Zhejiang Province) as well as the middle and eastern areas of Japan and Korea. Due to its limited distribution and restricted population number, this species has been listed as a member of the national grade Ⅱrare and endangered plants. Up to date, however, the study on the biological peculiarity and endangered mechanism of this species is still unknown. Therefore, this study focuses on these issues with respect to ecology, morphology and anatomy, embryology and conservation genetics of this species. This study aims to provide necessary data for the establishment of scientific and effective conservation strategy for this endangered species. The conclusions are as follows: 1. In China, K. palmata is disconnectedly distributed on the Huangshan and Tianmushan mountain series at the junction of Anhui and Zhejiang Province. Altitude and light are the two main factors that limit the distribution of this species. The habitat of the species is usually shady and cool. This plant are frequently found to grow in a cluster in the evergreen and deciduous broad-leaved mixed forests at the altitude of 700m to 1500m, with the main co-habitat plants of Hydrangea paniculata Sieb., Magnolia sieboldii K. Koch. Sand and Cimicifuga acerina (Sieb. et Zucc.) Tanaka etc. growing together. 2. The leaf of K. palmata has the general characters of shady leaf, and is adapted to grow in forestry with middle or higher altitude. In addition, the epidermis trichomes are featured by clear protuberances composed of silicon, which is similar to that of Deutzia of Hydrangeaceae. This character could be derived from the result of adaptation to unfavorable environments, such as cold and water menace. 3. The roots of K. palmata are composed of fibres. In its secondary root structure, the periderm is marked and there are several specialized layers of parenchyma between the periderm and vascular bundle. It can be postulated that this structure was obtained from the results of adaptation of this species to the alpine habitat. Conversely, it can strengthen this species′ability to resist hard conditions. 4. The seed of K. palmata is dormant. The potential ability of germination (87.4%) by the method of TTC, is much higher than its effective level of germination (28.9%) in its habitat soil. This result is consistent with few seedlings in its natural habitats through our investigation. The reasons resulting in the obvious decline of germination rate may be the sensitiveness of K. palmata to the conditions of germination, especially seed coat and microorganism in soil being the two key affecting factors. 5. The anther is tetrasporangiate, and its wall is composed of four layers: epidermis (persistent), fibrous endothecium (fibrous thickening), middle layers (ephemeral) and glandular tapetum. Simultaneous cytokinesis in the microspore mother cell follows meiosis and the microspore tetrads are tetrahedral. Pollen grains are 2-celled when shed. The ovule is anatropous, bitegmic and crassinucellar. The development of the microspore/macrospore and male/female gametophyte is basically normal. Therefore, the above processes are not the weak tache of the sexual reproduction of K. palmata. 6. The 13 selected primers were used to amplify the 72 individuals from four extant natural populations in China. The percentage of polymorphic bands (PPB) for this species was 79%. The average effective number of alleles per locus was 1.4625. The average gene diversity (He) was estimated to be 0.2586. The average Shannon's index (Ho) was 0.3756. The coefficient of genetic differentiation between populations (Gst) was 0.1669 and the level of gene flow (Nm) was estimated to be 2.4958 individuals per generation between populations. Comparing with the genetic parameters of other plants including some endangered species, this study revealed a relatively high level of genetic variation in K. palmata and low level...