Study On The Maximum Sustainable Yield Of Akebia Trifoliata (Thunb.) Koidz

Akebia trifoliata (Thunb.) Koidz. is an defoliated or half-evergreen, perennials liane of akebia, lardizabalaceae, which is regarded as an important Chinese traditional medicine and adapts to warm wet and sciophilic habitat. Most ofA. trifoliata distribute in the Yangtse River valley, at the south of Shaanxi province, the southeast of Gansu province and the south of Shanxi province, and also in some places of Hu'nan, Hubei, Jiangxi and He'nan province. The main valid components in rattans are manifold triterpenoid saponins such as oleanolic acid and hederasaponin with curative effects of diuresis, diminishing inflammation, dehumidifying, easing pain and so on, and it could also be used as the therapy for arthritis and osteomyelitis, etc. Since Aristolochia manshuriensis Kom. (AMK), one of the components in Longdan xiegan pill (a Chinese .Patent Medicine), was forbidden because of a renal injury side-effect, the value of A.trifoliata is more and more recognized and widely applied in modem medical industry. Studies about micromorphology, population ecology and quantitative ecology were conducted on the basis of population investigation of wild A. trifoliata in Zhen'an county, China, and the model of maximum sustainable yield was also established.The foliar surface structure of wild A. trifoliata distribute in Zhen'an Shaanxi have been observed by environmental scanning electron microscope. The results demonstrate that: the shape of the epidermal cells is ruleless; there are veriform cutin on the face of leaf adaxial epidermis, which are coverd with different wax; there are tubers distribute on abaxial epidermis, which shape are trigonal and papilla; the stomatal apparatus is anomocytic type, which only distribute on and sink into abaxial epidermis. This whole results of this study provid micro-morphological evidence for choiceness of A. trifoliata.Based on the investigation of A. trifoliata wild population in Zhen'an county, we identify eight different quantitative characteristics of leaves in different samples and plant ages, and examine the relationship between quantitative traits, environmental factors and ages by ANOVA, multiple comparisons and correlation analysis. The evidence shows that the eight quantitative characters vary significantly across different samples and ages. Moreover, it is found that the different characters differ in their own ways. Namely, the variation of length of petiole (L_p) is the largest (variance coefficient is 30.8%), the second largest one is the width of tip leaf (W_TL)(27.4%) and the ratio of petiole length to total length (RPT) has the smallest variation(13.0%), all of them correlated negatively with several environmental factors, such as slope direction, DSF, GSF, DirBe, TotBe; which indicates that the L_p and W_TL are more incline to be affected by environmental factors while the RPT seems less sensitive to the environment. Due to the fact that the shape of leaf is defined by the ratio of length to width of leaf (RLW_L), the ratio of length to width of tip leaf (RLW_TL) and RPT, there are no significant variances in those three traits among plants in various ages base on the multiple comparisons analysis, which means that the shape of the leaf is stable. The result of relative analysis indicates that these quantitative characters are both affected by the environment and the plant growth status. Furthermore, it is supported that there is a close relationship between the quantitative characteristics of various leaves. This study is expected to provide sound reference and theoretic basis for establishing excellent artificial foster model and the resources protection.The character of community of A. trifoliata and the relationship between which and environment was investigated with the method of clustering and PCA ordination, and the quantitative interpretation of community type and the environmental gradients was given by the multivariate regression analysis. The results show that, all sampling plots are classed to 2 kinds; the underlying effects of environment gradient to the population distribution is reflected by PCA, two regression equation are received: Y₁=0.644 + 0.012X₂—0.005X₄ (R₂=0.509,P＞0.05), Y₂=1.557 + 0.01X₁—0.069X₂ (R₂=0.797,P＜0.01). Clustering and PCA have the same results, the primary environmental factors which decided the distribution of community of A. trifoliata are altitude and gradient, different plants distribute in different places according to altitude and gradient.The leaf area index, ellipse leaf angle distribute parameter, leaf inclination angle, canopy coverage and the light resource were studied systematically to analyze the canopy structure characteristics of wild A. trifoliata population, by using the Hemiview digital canopy analysis system. No significant differences was found in any characteristic data of canopy and light resources among different sampling sites (P＞0.05) but there are negative correlation between leaf area index and the degree of coverage(P＜0.05), positive correlations between leaf area index and leaf inclination angle (P＜0.01), negative correlations between leaf inclination angle and the degree of coverage and the total radiation beneath canopy is positively correlated with direct site factor, indirect site factor and global site factor (P＜0.01). Both the diffusion radiation below canopy and direct beam beneath canopy are positively correlated with total radiation beneath canopy (P＜0.01) while the latter is not correlated with leaf area index significantly (P＞0.05) but negatively correlated with the degree of coverage (P＜0.01). The analysis result of ellipse leaf angle distribute parameter is consistent with the growth characteristic of A. trifoliata and leaf area index changed with plant development. The results are expected to provide valuable insight into improving the canopy structure of A. trifoliate further and predicting potential canopy photosynthesis.An investigation is conducted on population structure of A. trifoliata. The time-specific life table, survival curve, death curve and age structure are obtained. The results show that the types of A. trifoliata population in Zhen'an are increasing and the type of survival curve is Deevey typeâ…¢. Function of survival ratio, funded death ratio, death density and hazard ratio fluctuat rather obviously, the function of survival ratio declines monotonously, but the function of funded death ratio keeps rising all the time, the fluctuations in prophase and anaphase are bigger, and the latter is much bigger than the former, which is mild in metaphase. During the whole life, the expected life-span in 5a-8a age grade is the biggest, which is in the blooming period, while the wane begins in 25a.Finally, based on the study results of population age structure, we studied the rule of growth in A. trifoliata and drafted the growth equation using the three-point method of Logistic equation, the logistic growth curve also was drawn. We put forward a more reasonal and effective harvest project on the basis of consulting some experience on fishery and stockbreeding. The results show that: (1) the quantity of containing water in stem is 50% in average, there is linear correlation between the dry weight and fresh weight(P＜0.01); (2) the best harvest age is 22a～23a, the diameter in bosom is 1.23cm correspondingly.All in all, firstly, it is important and meaningful to make the A. trifoliata in Zhen'an, Shaanxi province as the object of this study, the study results could be applied in the areas through the whole country where the A.trifoliata distributed densely. Secondly, It was expected that the results of studies on biological characters would provide micro-morphological evidence for choiceness ofA. trifoliata. Thirdly, provide valuable insight into further improving the canopy structure and predicting potential Canopy photosynthesis and find an excellent colony structure and optimal artificial planting pattern. Finally, it is also expected that the studies on maximum sustainable yield would provide a significant reference for efficient protection and application of such Chinese traditional medicine resources.