Analysis On Potential Distribution Of Cornus Officinalis Resources And Analysis Of Environmental Factors Affecting The Formation Of Effective Components

The air-dried pericarp of Cornus officinalis Sieb. et Zucc. is one of the traditional bulk Chinese medicines that possesses important pharmacological effects of nourishing vitality and conserving deficiency, eliminating phlegm and promoting digestion, regulating immune and anti-tumor. In addition, C. officinalis has a wide range of applications in food development, healthy drink process, vegetation protection and landscape architecture. In recent years, the strategy of modernization for traditional Chinese medicine has been implemented in our country. Specifically, a series of great breakthroughs were achieved in the theoretical research regarding clinical applications of C. officinalis. This has thus led to the increasing demand for C. officinalis, while the wild resources gradually exhausted. With the implementation of "Return the Grain Plots to Forestry" project, C. officinalis was introduced and cultivated in many areas in China, regardless of local environment suitability. Since C. officinalis was not well grown in these areas, its yield and quality were seriously decreased. Therefore, the suitable habitat of C. officinalis should be predicted in the aspect of modern niche theory for resource conservation and utilization of medicinal plants, thereby conducting further work on plantation regionalization. Meanwhile, it still remains unclear whether the fruit traits, the content of active ingredients and the amount of nuclear DNA of medicinal plants were affected and regulated by environmental variables. It will provide valuable theoretical references for revealing the formation mechanism of geo-herbalism of medicinal plants by solving this problem.In this study, we used combined Maxent modeling and fuzzy logics, together with GIS technique, to reveal the potential distribution areas of each suitability level and the range of determinant environmental variables of C. officinalis. The materials included117specimen records and253loganin contents of C. officinalis germplasms as well as local environmental variables collected from the main producing areas in Shaanxi, Henan and Zhejiang provinces. On the basis of potential distribution prediction, we then conducted plantation regionalization of C. officinalis in Shaanxi province. Furthermore, we optimized the estimation methods of C-value in tannin-rich medicinal plants through estimating the nuclear DAN content of C. officinalis collected from Shaanxi, Henan and Zhejiang provinces using flow cytometry (FCM). Accordingly, we further discussed the correlations between fruit traits, loganin content and C-value of C. officinalis and their relationship with environmental variables. Our main results are as below:1. We collected117specimen records and253loganin content data of C. officinalis germplasms from the main producing areas in Shaanxi, Henan and Zhejiang provinces. With the minimum content of0.6%(in pharmacopeia) as standard, we assigned and standardized the map layers of each environmental variables using fuzzy logics. The statistically significant AUC value (0.980) of ROC curve indicated high accuracy and reliability. The suitable areas of C. officinalis were determined in the northwest, the central and the east of China, where the "Qinling Mountain-Tianmu Mountain-Funiu Mountain zone" was the core distribution region. This region includes the cities of Hanzhong, Ankang and Shangluo in Shaanxi province, the city of Nanyang in Henan province, the city of Bozhou in Anhui province and the city of Lin’an in Zhejiang province. The potential distribution areas could be divided into four suitable classes, and the good and high suitable classes cover areas of264316and155351km2, respectively. The result showed that the six environmental factors including tmin3(contribution23%), prec3(contribution17.6%), bio4(contribution13.3%), bio12(contribution9.5%) and alt (contribution9.1%) were determined as key influential factors that mostly affect both the habitat suitability and active ingredients of C. officinalis. Furthermore, we conducted statistical analysis on the range of each suitable classes for the above environmental variables, which will provide references for the suitability evaluation, standardized cultivation and plantation regionalization of C. officinalis.2. On the basis of potential distribution prediction, we made a primary regionalization of C. officinalis in Shaanxi province according to the ecological zone principle. Our result divided the producing areas of C. officinalis into two main producing regions and four sub-producing regions. The first region was the South warm temperate zone plantation region, which covers the largest plantation area of C. officinalis in Shaanxi province. This region could be divided into two sub-regions as below:1-1Qinling Mountain humid climate plantation region, and1-2Shangluo Danjiang River Basin semi-humid climate plantation region. The second region is North subtropical zone plantation region. This region is divided into two sub-regions as below: Ⅱ-1Hanzhong-Ankang Hanjiang Valley Basin humid climate plantation region, and Ⅱ-2Micang Mountain-Daba Mountain humid climate plantation region. Furthermore, we proposed the structural readjustment for plantation arrangement and the production base construction of C. officinalis in Shaanxi province. These results will lay solid foundation for the extensive plantation and standardized production of C. officinalis.3. We optimized the optimal estimation methods of genome size for tannin-rich medicinal plants (C. officinalis). The estimation condition is as below. Pre-soaking the silica gel-dried leaf of C. officinalis for15min using Otto I. Taking out the leaf and reloading1mL Otto I in4℃. Chopping the leaf with young leaf of the standard Vicia faba quickly and vertically. Filtering the mixture with30um filter. Centrifuging the nuclear suspension in4℃for2min using strength in1.0×103g. According to the above methods, we first estimated the2C value of C. officinalis as5.92pg and the genome size as2893Mbp. The new methods proposed here will provide valuable references for the estimation of C-value, genome size and ploidy level in tannin-rich medicinal plants.4. On the basis of successful estimation of C-value of C. officinalis in China, we collected the fruit and seed traits and loganin content data of C. officinalis in Shaanxi, Henan and Zhejiang provinces of China, together with previous estimation of C-value of C. officinalis in Madison, USA. The environmental variables in the localities of specimen records were extracted. We then conducted correlation analysis between phenotypic traits, loganin content and genome size of80C. officinalis germplasms in China and USA, and discussed the interaction relationship between the above traits and environmental variables. Our results showed that fruit length, seed width,100-dry fruit weight,100-dry pericarp weight and percentage of dry pericarp of C. officinalis germplasms from Madison, USA were significantly larger than those from China, but the loganin contents and2C values of germplasms from China (0.9%and5.92pg) were significantly higher than those from Madison (0.6%and5.29pg)(P<0.01). The correlation analysis suggested loganin content of C. officinalis was significantly correlated with some environmental variables (P<0.001). The above results indicated that C. officinalis had a tendency to decline in genome size and loganin content during the long period of adaptation and evolution with new ecological variables. We are able to presume that ecological variables are the key factors in determining phenotypic diversity, genome size and active ingredient of medicinal plants.