不同生境朝鲜淫羊藿生长与光合特征

选择朝鲜淫羊藿野外生存的林缘、林窗和林下3种生境,研究朝鲜淫羊藿形态特征、光合特征、叶绿素含量、生物量积累及分配对不同光环境的响应。结果表明,朝鲜淫羊藿株高、茎径、总叶面积等形态指标随光照强度减弱明显减小,各生境间差异显著。随光照强度降低,朝鲜淫羊藿的净光合速率、水分利用效率、气孔限制值、叶绿素a/b降低,而胞间CO2浓度、光能利用效率、叶绿素b和总叶绿素含量增加。各器官生物量积累随光照强度减弱而降低,各生境间差异极显著,其中,林缘地上生物量是林窗的1.6倍,林下的3.1倍。生物量分配方面,叶生物量比、叶面积比率、比叶面积随光照强度减弱而增加,根状茎生物量比和根冠比降低,林缘、林窗与林下差异极显著;林下、林缘、林窗朝鲜淫羊藿地上部分生物量比分别为0.733、0.659、0.664,林下朝鲜淫羊藿与林缘、林窗存在不同的光利用策略和生存策略。朝鲜淫羊藿作为极易遭受利用和生境破坏威胁的物种,宜在适度荫闭的林缘和疏林下开展野生抚育或仿生态栽培。

Growth and photosynthetic characteristics of Epimedium koreanum Nakai in different habitats

Epimedium koreanum Nakai is a perennial herb of Berberidaceae, a common traditional Chinese herb officially listed in the pharmacopoeia of the People's Republic of China and distributed in Changbaishan Mountains, coast of Japan Sea and North Korea. From the beginning, the sources of traditional Chinese herbs are mainly wildly grown plants, but this situation cannot be maintained since the growing demand of the increasing population and higher dosage devastate the natural resources. So the agricultural cultivation and wild-simulated production are efficient methods for protecting the wild resource and meeting the supply. The optimal ecological factors are keys to production. The characteristics of morphology, photosynthesis, chlorophyll content and accumulation and allocation of biomass were studied in three habitats (the open land of forest edge, forest edge and forest understory, respectively), differing mainly in light intensity and crown density. Samples and investigation were obtained on Cuocao Groove (126°39'E, 41°45'N), the Southeast foot of Changbaishan Mountains, Jilin Province, China. The parameters (Pn, Tr, Gs and Ci) of E. koreanum in different habitats were tested by LCpro+ portable photosynthesis. After testing, 20 entire plants in each habitat were grubbed up. The characteristics of morphology and the biomass of different organs in total plant were taken. The chlorophylls were extracted with acetone and the contents were determined by ultraviolet spectrophotometry. The results showed that the plant height, stem diameter, total leaf area and other morphological indexes decreased with the weakening of light intensity, the same as the Pn, WUE, Ls, Chl a/b and biomass accumulation of organs. On the contrary, the Ci, LUE, Chl b and total Chl increased. The differences at morphological indexes and biomass accumulation were significant at 0.05 level (P<0.05) and 0.01 level (P<0.01) in different habitats, respectively. The aboveground biomass at forest edge was 1.6 times and 3.1 times to that at the open land of forest edge and forest understory, respectively. As far as the biomass allocation, the leaf biomass ratio, leaf area ratio and specific leaf area increased with the weakening of light intensity. In contrast, the rhizome biomass ratio and ratio of rhizome/shoot decreased. The biomass allocation in three habitats were very significantly different (P<0.01). The aboveground biomass ratios were 0.733, 0.659 and 0.664 at the forest understory, forest edge and open land of forest edge, respectively. The utilizing light way and surviving way of E. koreanum at different habitats were different. The ecological factors of forest edge and open land of forest edge were more beneficial to clonal growth of rhizome than that of forest understory. This paper can provide a scientific basis for the utilization and management of wild resource and the bionic cultivation of E. koreanum.