Studies On Morphological And Physiological Responses Of Medicinal Plant Pinellia Ternata (Thunb.) Breit. Under Different Simulated Environmental Conditions

Pinellia ternata (Thunb.) Breit., a Araceae Pinellia perennial herb, there is extensive distribution in most regions of our country, its main production region is in Sichuan, Hubei, Anhui, Jiangsu, Henan, Shandong and other provinces. And Sichuan province experiences the great production capacity and good quality. P.ternata has great medicinal values, such as eliminating dampness and phlegm, anti-vomiting, relieving and eliminating mass and so on. Current research concerned with P. ternata has been focused on its medicinal value; as for research related to large area normative cultivated planting and physiological characteristic aspects, only a few research has been carried out. The research object in this paper is P. ternata, with the simulated acid rain stress, fertilizing and shading conditions, the preliminary statistics and analysis were taken by managing the change of morphological indicators, changes physiological indicators and changes in tuber's medicinal contents. The purpose of this is to investigate how the different adverse circumstances and growth conditions will affect P.ternata's physiology suitability and its tuber's medicinal contents; to understand which condition is more suitable for P.ternata's growth; and to provide scientific evidence for the conservation of wild P.ternata, artificial cultivation and improving the medicinal contents in its tuber. The research results are as follows:1. In the simulated acid rain treatment progress, the impact of different treatment levels on the morphology of P.ternata in descending order is:comparison(CK)>mild acid rain>moderate acid rain>severe acid rain. The growth rate of P.ternata's modality characteristic will decrease with the decrease of pH value. The photosynthetic pigment content in descending order is comparison(CK) >mild acid rain>moderate acid rain>severe acid rain, from comparative analysis it concludes that:acid rain stress reduces the photosynthetic pigment content. The lower of pH value, the rate of decrease will be larger. Along with the increase of time, the influence of acid rain on photosynthetic pigments will increase. As for the impact with protective enzymes and protective substances:POD activity in severe and moderate acid rain stress is increased at first and then decreased, and it is slowly rising in mild acid rain condition. The greater the stress level, the greater impact appears; With the greater degree of stress, the activity of SOD and CAT is higher; soluble protein and soluble sugars has not been affected obviously in the early and medium term treatment. In the later period of treatment, compared with the controlled samples, the content was significantly decreased, and the greater the stress level, the greater the downward trend; the free proline content was increased at first and then decreased; MDA content was increased, the greater the stress level, the higher the content. The total alkaloids, guanosine and adenosine content in P.ternata's tuber were obviously decreased by acid rain stress, and the greater the stress level, the content will be lower. From analyzing results it represents that:acid rain plays a significant effect on the growth of P.ternata, and the inhibitory effect for P.ternata will be more obvious when pH value is decreasing.2. Under the fertilizing and shading treatment:P.ternata's various morphological indicators with fertilization are larger than without fertilization, and combined treatment of fertilizing and moderate shading has the largest positive impact on the growth of P.ternata caudex and leaf morphology. The combined treatment of fertilizing and severe shading has the most significant benefit on the growth of leaf water content and root morphology. The photosynthetic pigment content under fertilizing treatment was larger than non-fertilizing treatment, and content under shading treatment was larger than non-shading treatment, and content with moderate shading was greater than the severe shading. Under the combined treatment of fertilizing and moderate shading, photosynthetic pigment content had the highest value. As for the impact with protective enzymes and protective substances:there was no obvious impact on POD, CAT and SOD activity in the fertilizating condition; but the soluble protein and soluble sugar content was increased in the fertilizating condition. In fertilizing condition, the free proline and MDA content was larger than non-fertilizing condition. The greater degree of shading, the activity of POD and CAT was higher, and SOD activity will stand on high level with no shading and severe shading conditions instead of moderate shading; the soluble protein and soluble sugar content represented that:moderate shading >severe shading>no shading; the free proline content in non-fertilizing and non-shading conditions will reach the highest, and achieves the tolerance limit after the later term treatment; MDA content will be the highest in severe shading condition. The content of total alkaloid, guanosine and adenosine illustrates that:content in fertilizing condition was greatrer than non-fertilizing condition, content with shading is greater than no shading. Under the combined treatment of fertilizing and moderate shading, the content of P.ternata's total alkaloids, guanosine and adenosine will be the largest. In the later period of treatment, they were increased by 54.8%, 38.2% and 37.2% respectively compared with the controlled samples. From analyzing results it represents that:combined treatment of fertilizing (NH4NO3:2g,NaH2PO4:2g,K2SO4:2g per plant) and moderate shading(20% of natural sunlight) has significant effect on the increase of P.ternata's photosynthetic pigment, protective substances and medicinal contents.