Responses And Physiological Mechanism Of Root Yield And Quality Of Angelica Sinensis (oliv.) Diels To Altitudes

Angelic sinensis is one of the genuine medicinal materials of Min County in Gansu province,and Min Angelic sinensis renowned at home and abroad because of its high quality. However,the limited appropriate ecotopes and traditional customs of planting Angelic sinensis on relatively smooth and low altitude land led to the lack of planting area,and further led to the situation that the supply is inadequate to meet the demand. In order to explore the appropriate planting area of Angelic sinensis from existing ecological resources,ecological adaptability tests (field and pot experiment) were conducted in Chabu country of Min County in Gansu province during 2009-2010. In this study,we discussed the difference of yield and quality of Angelic sinensis and revealed the influencing mechanism of altitude on yield and quality of Angelica sinensis from protective enzyme,osmotic regulation substances and photosynthetic characteristics,to look for the key factors and its influence size to effect yield and quality of Angelic sinensis. The main results are as follows:1. Altitudes effected the Angelic sinensis yield formation through changing sink-source relationships and dry matter accumulation rate. The partitioning of photosynthates to root arrived ahead of time and dry matter accumulation rate increased with the increase of altitude. Partitioning of photosynthates in Angelic sinensis of 2780m altitude to root began 10 days ahead than the others and the percentage of photosynthates distribute to root was much more than the latter in later growth stage,which a solid base for the yield formation of Angelica sinensis in harvest period. Biological yield increased by 33.1%,43.7% and 46.7%,respectively,with the increase of altitude,compared with than in flat land. The sequence of Angelic sinensis root yield was 2570m(28.4g/plant),2780m(26.6g/plant) and 2360m (21.8g/plant),and the root yield of 2360m treatment significantly decreased by 22.6% and 20.8% compared to the other altitudes(P<0.05).The variance of root yield and dry matter accumulation rate reduced with the increase of altitude.2. Altitudinal gradients significantly influenced the photosynthetic pigment content and photosynthetic parameters of Angelic sinensis. The carotenoids,net photosynthetic rate(Pn),stomatal conductance(Gs) and intercellular CO₂ concentration(Ci) were decreased,but the chlorophyll content was increased and transpiration rate(Tr) increased in 2570m treatment then decreased Along with altitude elevating,Carotenoids content decreased by 14.3% and 55.4%,mean net photosynthetic rate decreased by 10.0% and 18.4%,stomatal conductivity decreased by 5.3% and 16.0%,mean intercellular CO₂ concentration decreased by 7.6% and 14.0%,chlorophyll-a increased by 7.9% and 70.5% and chlorophyll-b increased by 21.1% and 75.8%,compared 2570m and 2780m treatments with 2360m treatment. Mean transpiration rate significantly increased by 13.3% in 2570m treatment and significantly decreased by 13.3% in 2780m treatment compared to that in 2360m treatment.Analysis of environment factor influencing the net photosynthetic rate showed that the air relative humidity was the key factor,followed by photosynthetic available radiation (PAR) and air CO₂ concentration.3. The excessive accumulation of active oxygen metabolism caused by high temperature in low altitude area led to the formation of MDA which is the membranous peroxide and can produce a toxic effect on cells in Angelica sinensis. Angelic sinensis reduced the toxicity of MDA by increasing the content of cell osmotic regulation substances and this was consistent with Angelic sinensis'properties of being fond of cool ecological conditions. MDA content decreased with the increase of altitude that in 2360m treatment was significantly increased by 52.4% and 38.1% compared with that in 2570m treatment and 2780m treatment (P<0.05);The reducing range between treatments decreased with altitude elevating,it was 52.4% and 30.0%. Free proline content showed the altitude effect of "high—low—high" and there was no significant difference between the treatments in 2360m and 2780m,but free proline content in the two treatment above was significantly higher than that in 2570m,and increased by 12.4% and 13.6%,respectively. The variation ranges of free proline content between treatments increased by 12.4% and 13.6%with the increase of altitude. Soluble sugar content of 2360m and 2570m treatments were significantly higher than that of 2780m by 19.7 % and 14.7% (P<0.05),while the difference between the treatments of 2360m and 2570m was not significant(P>0.05),the variance range in three altitudes were increased by 7.7% and 14.7% with altitude elevatsing. The analysis of the relationship between osmotic regulation substances and membranous peroxidation product showed that the change of osmotic regulation substances content was in accordance with the change of MDA content,and there was a complementary relationship between the content of osmotic regulation substances.4. Low altitude caused active oxygen metabolism disordere,active oxygen accumulation and finally the formation of MDA in Angelic sinensis. In order to sheltered cells from the suffering of MDA,Angelic sinensis'cells increased the antioxidant enzymes activity to decompose peroxide. The studies showed that SOD activity reduced with the increase of altitude,and that in 2780m treatment was decreased by 40.8% and 39.3%,relatively,compared with that in 2360m and 2570m treatments (P<0.05). The reducing range of SOD activity in three altitudes were increased with altitude elevating,and that in 2570m treatment was significantly decreased by 2.5% compared to that in 2360m treatment and that in 2780m treatment was significantly decreased by 39.3% compared to that in 2570m(P<0.05). CAT activity reduced with the increase of altitude and that in 2780m treatment significantly decreased by 13.6% and 17.1% compared to that in 2360m and 2570m treatments (P<0.05). The reducing range of CAT activity in three altitudes were increased with the increase of altitude,it was 13.6% and 14.6%. POD activity showed the tendency of rising at first and then decreased with the increase of altitude. POD activity in 2780m treatment was lowest and lowered by 26.1% and 31.5% compared to that in 2360m and 2570m treatments and the difference between them were significant (P<0.05). The reducing ranges of POD activity in three altitudes were increased with the increase of altitude and it was 4.27% and 24.0%,respectively. The correlation analysis between protective enzyme and MDA showed that the content of MDA and CAT had a significantly positive correlation (R²=0.3068) and the POD,SOD and MDA are significantly positively correlated with each other (R²>0.96).5. Ferulic acid content in Angelic sinensis root was increased with the increase of altitude,Ferulic acid content of Angelic sinensis in 2780m treatment was significantly increased by 14.5%(P<0.05) compaed with 2360m treatment,while there were no significant difference between 2570m treatment and the other two altitudes. The variation scope of ferulic acid content decrease with the increase of altitude and there were no significant difference between them.6. The yield and amount of essential oil,relative ligustilide content in Angelic sinensis increased with the increase of altitude. Yield of essential oil in Angelic sinensis in 2360m treatment,was 0.86% and it was the lowest in all treatments and was decreased by 11.6% and 14.0% compared to that in 2570m and 2780m treatments,respectively. Essential oil content under three altitudes were 85.5%,95.16% and 96.67%. GS-MS analysis showed that ligustilide was the main chemical compositing of essential oil and the relative content in Angelic sinensis of three altitudes were 58.72%,60.91% and 61.59%,respectively,and there were no significant difference between them. Synthetic analysis of ligustilide and its isomer showed that the content in 2570m treatment (64.28%) and 2780m treatment (65.29%) were increased by 8.97% and 10.68% compared with that in 2360m treatment,respectively and the difference between that in 2780m treatment and 2360m treatment was significant(P<0.05).7. Correlation analysis showed that the key ecological factors effecting the yield and quality of Angelic sinensis was temperature and rainfall which has the correlation degree from 0.7417 to 0.9714,sunshine hours. MDA and soluble sugar were the key physiological and biochemical factors effecting yield of Angelic sinensis (R²=-0.9118) and the determination coefficients were -0.9118 and -0.8831,respectively. The physiological and biochemical factor effecting ferulic acid of Angelic sinensis,the soluble sugar was of first importance (R²=0.9749) and then followed by SOD (R²=0.8408). The physiological and biochemical factors effecting essential oil of Angelic sinensis,soluble sugar (R²=-0.8990) and MDA (R²=-0.8958) were of first importance and then followed by SOD (R²=-0.7226). In the photosynthesis parameters,that effecting the yield of Angelic sinensis,Ci(R²=-0.7393) and Pn(R²=-0.7332) were the key factors and followed by RH (R²=-0.5955),Gs(R²=-0.5553) and PAR(R²=-0.5277),in that effecting ferulic acid,RH(R²=0.9699) was the key factor and followed by PAR(R²=0.9467),Chlb (R²=0.9380)and air temperature(R²=-0.9050),and in that effecting effect essential oil of Angelic sinensis,Ci(R²=-0.9706) and Pn(R²=-0.96849) were the first important,followed by RH,Gs,PAR and air CO₂ contentration. Comprehensive analysis showed that the key photosynthesis parameters effecting the yield and quality of Angelic sinensis were Ci, Pn, RH, PAR and air CO₂ contentration.Based on the results described above, the yield and quality of Angelic sinensis increased with the increase of altitude. From the angle of ecological factors, the reduce of temperature and the the increase of rainfall are beneficial to the yield and quality of Angelic sinensis. From the angle of physiological and biochemical factors,the reduce of MDA content,soluble sugar content and protective enzyme activity are beneficial to the formation of the yield and quality of Angelic sinensis. From the angle of photosynthesis parameters,the increase of air relative humidity,photosynthetically active radiation (PAR) and air CO₂ density are beneficial to the yield increasing and quality improving. So,in the altitude range from 2300m to 2800m,we suggested expanding the cultivation areas of Angelic sinensis.