Effects Of Calcium On Physiological And Biochemical Characteristics Of Pinellia Ternata And The Differential Expression Of Jasmonic Acid In Pinellia Bulbils

Pinellia ternata（Thunb.）Breit.is a perennial herb in Araceae Pinellia,and has been widely applied as an antitussive and expectorant in common traditional Chinese medicine.As the main component of cell wall and intercellular layer,calcium is involved in the combination of protein and carbohydrates,regulating the balance of physiological activities in plants.In this study,calcium treatment of different concentrations of P.ternata was carried out in 6-8 months to compare the physiological characteristics of the antioxidant system,the changes of photosynthetic physiological parameters and the accumulation of effective components in the P.ternata.Furthermore,we have explored the application concentration of the calcium fertilizer,which provided a theoretical basis for the large area and reasonable cultivation of P.ternata and the higher yield.The main line of this study is to increase P.ternata yield and optimize cultivation techniques.Not only can we explore the factors affecting the physiological and biochemical levels,but also explore the regulatory factors on the level of hormone.Jasmonic acid（JA）is a kind of growth regulating hormone,which is widely used in plants.JA as a signal molecule can often participates in plant growth and stress response,which play an important roles in regulating the growth of plant roots,the formation of bulbils,the development of fruit ripening,etc.As an important breeding method of P.ternata,the multiplication of bulbils was sequenced by high throughput sequencing technology,and the expression of JA was found in the bulbils by differential gene expression analysis.Therefore,the molecular regulation mechanism of Jasmonic acid in bulbils was explored to provide scientific guidance for improving the yield and quality of bulbils.The main results of this study are as follows:（1）The cultivation research of Pinellia ternata was carried out in Hangzhou.Based on the index of antioxidant activity,the experimental results showed that Ca²⁺could promote the activity of three enzymes of POD,CAT and SOD in P.ternata.When the concentration of Ca²⁺increased gradually,the activity of three enzyme had a tendency to rise first and then descend.At the Ca²⁺concentration of 600mg/L,the activity of three enzymes was the highest and the content of osmotic substances was higher;Meanwhile,the content of MDA and superoxide free radical content decreased had a tendency to decreased first and then increased,and the lowest at 600mg/L concentration.This indicates that 600mg/L concentration of Ca²⁺treatment are favorable for the growth of P.ternata.（2）With the increase of Ca²⁺concentration,the content of chlorophyll was obviously increased,while the electron transfer rate（ETR）,the photosynthetic quantum yield（Yield）and the photochemical quenching coefficient（qP）showed a tendency to rise first and then descend.The non photochemical quenching coefficient（NPQ）decreased first and then up,and the Ca²⁺concentration of 600mg/L treatment indicated that NPQ lower,qP higher,Yield higher and ETR also enhanced.The photosynthetic parameters have significantly increased leaf Photosynthesis（Pn）,Transpiration rate（Tr）,and reduced intercellular CO₂ concentration（Ci）.Therefore,Ca²⁺can increase the chlorophyll content,improve the chlorophyll fluorescence parameters,and then promote physiological metabolism and improve photosynthesis,which plays an important role in improving the resistance of P.ternata.（3）With the increase of Ca²⁺concentration,the leaf protein content,total alkaloid content,total soluble sugar content and the content of guanosine and adenosine in the P.ternata showed a trend of rising first and then decreasing.When the Ca²⁺concentration with the range of 400mg/L to 600mg/L,the content maintained a high level.Therefore,At the time of Pinellia total seedling that the foliar application of calcium fertilizer on the medium concentration is conducive to the accumulation of effective components of P.ternata.（4）To understand the process of bulbil development in P.ternata,we first used bulbils and stems as materials to survey the relationship between effective substance and plant hormone at the RNA level by high throughput sequencing technology.After the analysis of NR,KOG,GO and KEGG pathway,we screened seven differentially expressed genes related to Jasmonic acid（JA）metabolism.According to the GO annotations and KEGG analysis,we identified 7 unigenes coding for four key enzymes involvedinJAmetabolism,includinglipoxygenase（LOXs）（comp53749_c0_seq1）,12-oxophytodienoicacidreductase（OPRs）（comp48844_c0_seq5）,phospholipase A2（PLA2s）（comp49877_c0_seq1,comp49877_c0_seq4,comp49877_c0_seq6,comp49877_c0_seq7）,allene oxide cyclase（AOC）（comp39838_c0_seq6）.Through qRT-PCR validation and differential gene saliency analysis,we discovered the expression of the seven genes in the bulbils of P.ternata was higher than that of the stem,and the expression level of JA in the bulbil of P.ternata was higher than that of the stem.