Melatonin increases leaf disease resistance and saponin biosynthesis in Panax notogiseng

Panax notoginseng (Bruk.) FH Chen is a valuable traditional herb in China, with saponins being the main medicinal components in its roots. However, leaf diseases are a major factor limiting growth and production of P. notoginseng. Melatonin is a ubiquitous signaling molecule associated with abiotic stress resistance. In this study, we investigated the role of melatonin in leaf disease resistance of P. notoginseng in field conditions. Additionally, saponin concentrations were analyzed to evaluate the suitability of melatonin use in agricultural practice. Our results showed that exogenous application of melatonin promoted the endogenous phytomelatonin accumulation via upregulation of genes involved in its biosynthesis. The application of 10 μM melatonin decreased the incidence of leaf diseases (gray mold, round spot, and black spot) by about 40% compared with the solvent control, which might have been due to the increased expression of genes associated with immunity and disease resistance. Furthermore, concentrations of saponins and expression of their biosynthesis-related genes were significantly increased by melatonin. Taken together, the data presented here suggested that melatonin could be used in agricultural management of P. notoginseng because it increased leaf disease resistance and biosynthesis of saponins.

The transcriptome variations of Panaxnotoginseng roots treated with different forms of nitrogen fertilizers

BACKGROUND

The sensitivity of plants to ammonia is a worldwide problem that limits crop production. Excessive use of ammonium as the sole nitrogen source results in morphological and physiological disorders, and retarded plant growth.

RESULTS

In this study we found that the root growth of Panax notoginseng was inhibited when only adding ammonium nitrogen fertilizer, but the supplement of nitrate fertilizer recovered the integrity, activity and growth of root. Twelve RNA-seq profiles in four sample groups were produced and analyzed to identify deregulated genes in samples with different treatments. In comparisons to NH[Formula: see text] treated samples, ACLA-3 gene is up-regulated in samples treated with NO[Formula: see text] and with both NH[Formula: see text] and NO[Formula: see text], which is further validated by qRT-PCR in another set of samples. Subsequently, we show that the some key metabolites in the TCA cycle are also significantly enhanced when introducing NO[Formula: see text]. These potentially enhance the integrity and recover the growth of Panax notoginseng roots.

CONCLUSION

These results suggest that the activated TCA cycle, as demonstrated by up-regulation of ACLA-3 and several key metabolites in this cycle, contributes to the increased Panax notoginseng root yield when applying both ammonium and nitrate fertilizer.

Comparative transcriptome and metabolome analyses provide new insights into the molecular mechanisms underlying taproot thickening in Panax notoginseng

BACKGROUND

Taproot thickening is a complex biological process that is dependent on the coordinated expression of genes controlled by both environmental and developmental factors. Panax notoginseng is an important Chinese medicinal herb that is characterized by an enlarged taproot as the main organ of saponin accumulation. However, the molecular mechanisms of taproot enlargement are poorly understood.

RESULTS

A total of 29,957 differentially expressed genes (DEGs) were identified during the thickening process in the taproots of P. notoginseng. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment revealed that DEGs associated with "plant hormone signal transduction," "starch and sucrose metabolism," and "phenylpropanoid biosynthesis" were predominantly enriched. Further analysis identified some critical genes (e.g., RNase-like major storage protein, DA1-related protein, and Starch branching enzyme I) and metabolites (e.g., sucrose, glucose, fructose, malate, and arginine) that potentially control taproot thickening. Several aspects including hormone crosstalk, transcriptional regulation, homeostatic regulation between sugar and starch, and cell wall metabolism, were identified as important for the thickening process in the taproot of P. notoginseng.

CONCLUSION

The results provide a molecular regulatory network of taproot thickening in P. notoginseng and facilitate the further characterization of the genes responsible for taproot formation in root medicinal plants or crops.

Transcriptome analysis of 1- and 3-year-old Panax notoginseng roots and functional characterization of saponin biosynthetic genes DS and CYP716A47-like

MAIN CONCLUSION

Transcriptome analysis revealed high expression of saponin biosynthetic genes may account for highly accumulated saponins in 3-year-old Panax notoginseng roots and DS and CYP716A47 - like were functionally verified by transgenic tobacco. Panax notoginseng is a well-known traditional medical herb that contains bioactive compounds known as saponins. Three major dammarene-type triterpene saponins including R1, Rb1, and Rg1 were found to be highly accumulated in the roots of 3-year-old plants when compared to those of 1-year-old plants. However, the underlying cellular mechanism is poorly understood. In this study, transcriptome analysis revealed that most genes involved in saponin biosynthesis in P. notoginseng roots augmented during their growth periods. The analysis of the KEGG pathway indicated that the primary metabolism, cell growth, and differentiation were less active in the roots of 3-year-old plant; however, secondary metabolisms were enhanced, thus providing molecular evidence for the harvesting of P. notoginseng roots in the 3rd year of growth. Furthermore, the functional role of DS and CYP716A47-like, two of the candidate genes involved in saponin biosynthesis isolated from P. notoginseng, were verified via overexpression in cultivated tobacco. Approximately, 0.325 µg g-1 of dammarenediol-II and 0.320 µg g-1 of protopanaxadiol were recorded in the dry leaves of transgenic tobacco overexpressed with DS and both DS and CYP716A47-like, respectively. This study provides insights into the molecular mechanisms for saponin accumulation in P. notoginseng roots during its growth period and paves a promising way to produce dammarenediol-II and protopanaxadiol via transgenic techniques.

Fertilizer N application rate impacts plant-soil feedback in a sanqi production system

Replant failure caused by negative plant-soil feedback (NPFS) in agricultural ecosystems is a critical factor restricting the development of sustainable agriculture. Soil nutrient availability has the capacity to affect plant-soil feedback. Here, we used sanqi (Panax notoginseng), which is severely threatened by NPSF, as a model plant to decipher the overall effects of nitrogen (N) rates on NPSF and the underlying mechanism. We found that a high rate of N at 450kgNha^-1 (450N) aggravated the NPSF through the accumulation of pathogens in the soil compared with the optimal 250N. The increased N rates resulted in a significant increase in the soil electrical conductivity and available nitrogen but a decrease in the soil pH and C/N ratio. GeoChip 5.0 data demonstrated that these changed soil properties caused the soil to undergo stress (acidification, salinization and carbon starvation), as indicated by the enriched soil microbial gene abundances related to stress response and nutrition cycling (N, C and S). Accordingly, increased N rates reduced the richness and diversity of soil fungi and bacteria and eventually caused a shift in soil microbes from a bacterial-dominant community to a fungal-dominant community. In particular, the high 450N treatment significantly suppressed the abundance of copiotrophic bacteria, including beneficial genera Bacillus and Pseudomonas, thus weakening the antagonistic activity of these bacteria against fungal pathogens. Moreover, 450N application significantly enriched the abundance of pathogen pathogenicity-related genes. Once sanqi plants were grown in this N-stressed soil, their host-specific fungal pathogen Fusarium oxysporum significantly accumulated, which aggravated the process of NPSF. This study suggested that over-application of nitrogen is not beneficial for disease management or the reduction of fungicide application in agricultural production.

Effects of Essential Oils from Zingiberaceae Plants on Root-Rot Disease of Panax notoginseng

Replanting obstacles of Panax notoginseng caused by complex factors, including pathogens, have received great attention. In this study, essential oils (EOs) from either Alpinia officinarum Hance or Amomum tsao-ko (Zingiberaceae) were found to inhibit the growth of P. notoginseng-associated pathogenic fungi in vitro. Subsequent GC-MS analysis revealed the chemical profiles of two plant derived EOs. Linalool and eucalyptol were found to be abundant in the EOs and tested for their antifungal activities. In addition, the synergistic effects of A. tsao-ko EOs and hymexazol were also examined. These findings suggested that Zingiberaceae EOs might be a good source for developing new green natural pesticides fighting against root-rot of P. notoginseng.

Continuous cropping of endangered therapeutic plants via electron beam soil-treatment and neutron tomography

Various medicinal plants are threatened with extinction owing to their over-exploitation and the prevalence of soil borne pathogens. In this study, soils infected with root-rot pathogens, which prevent continuous-cropping, were treated with an electron beam. The level of soil-borne fungus was reduced to ≤0.01% by soil electron beam treatment without appreciable effects on the levels of antagonistic microorganism or on the physicochemical properties of the soil. The survival rate of 4-year-old plant was higher in electron beam-treated soil (81.0%) than in fumigated (62.5%), virgin (78%), or untreated-replanting soil (0%). Additionally, under various soils conditions, neutron tomography permitted the monitoring of plant health and the detection of root pathological changes over a period of 4-6 years by quantitatively measuring root water content in situ. These methods allow continual cropping on the same soil without pesticide treatment. This is a major step toward the environmentally friendly production of endangered therapeutic herbs.

Impaired terpenoid backbone biosynthesis reduces saponin accumulation in Panax notoginseng under Cd stress

Panax notoginseng saponins (PNS) are major secondary metabolite of Panax notoginseng (Burk.) F.H. Chen. Previous studies identified that P. notoginseng planting soil usually with high content of Cd. However, the effects of Cd stress on the accumulation of PNS and the corresponding regulation mechanisms have yet to be reported. In the present study, the impact of Cd stress on the PNS accumulation of P. notoginseng was studied in pot culture experiments. The effect of Cd stress on antioxidant enzyme activity was studied using hydroponics. In addition, transcriptase sequencing analysis was used to study the effect of Cd stress on the expression of PNS metabolism transcripts in hydroponic experiments. Cd treatments significantly decreased the accumulation of PNS in the rhizome and main root. The sensitive concentration of antioxidant enzyme activity for both leaf and stem was 2.5μM, whereas the sensitive concentration for the root was 5.0μM. Transcriptome analysis showed that 5132 genes (2930 up- and 2202 downregulated) were regulated by 5.0μM Cd stress in the root of P. notoginseng. Among them, six upregulated differentially expressed genes (DEGs) were related to the methylerythritol 4-phosphate (MEP) pathway, whereas three of the downregulated DEGs were mevalonate kinase (MVK), phosphomevalonate kinase (PMK), and geranylgeranyl diphosphate synthase (type II, GGPS). Of the 15 transcripts selected for real-time quantitative-PCR, 13 were expressed in the same manner as identified using RNA-seq. In conclusion, Cd stress inhibited the accumulation of PNS in the root of P. notoginseng by reducing the expression of MVK, PMK, and GGPS in the terpenoid backbone biosynthesis pathway, and also caused by the removal of reactive oxygen species.

Application of RAD Sequencing for Evaluating the Genetic Diversity of Domesticated Panax notoginseng (Araliaceae)

Panax notoginseng, a traditional Chinese medicinal plant, has been cultivated and domesticated for approximately 400 years, mainly in Yunnan and Guangxi, two provinces in southwest China. This species was named according to cultivated rather than wild individuals, and no wild populations had been found until now. The genetic resources available on farms are important for both breeding practices and resource conservation. In the present study, the recently developed technology RADseq, which is based on next-generation sequencing, was used to analyze the genetic variation and differentiation of P. notoginseng. The nucleotide diversity and heterozygosity results indicated that P. notoginseng had low genetic diversity at both the species and population levels. Almost no genetic differentiation has been detected, and all populations were genetically similar due to strong gene flow and insufficient splitting time. Although the genetic diversity of P. notoginseng was low at both species and population levels, several traditional plantations had relatively high genetic diversity, as revealed by the He and π values and by the private allele numbers. These valuable genetic resources should be protected as soon as possible to facilitate future breeding projects. The possible geographical origin of Sanqi domestication was discussed based on the results of the genetic diversity analysis.

[Ecology suitability regions and ecological characteristics of Panax notoginseng (Burk.) F.H. Chen based on maximum entropy model]

The ecology suitability and ecological characteristics of Panax notoginseng (Burk.) F. H. Chen were studied to provide a reference for its artificial introduction and cultivation. The maximum entropy model (MaxEnt) and geographic information system (GIS) were used to investigate the global ecology suitability regions for Panax notoginseng (Burk.) F. H. Chen based on its 67 distribution points collected from global biodiversity information facility (GBIF), Chinese virtual herbarium(CVH) and the related references. The results showed that the possible ecological suitable regions of Panax notoginseng (Burk.) F. H. Chen were located in Yunnan, Guangxi, Guangdong, Guizhou, Hainan, Sichuan, Fujian and Chongqing provinces. The areas with ecological similarity higher than 60% were about 89 571.3 square kilometers in total, mainly distributing in Yunnan and Guangxi provinces and small portion was located in Guangdong and Guizhou provinces. The areas with ecological similarity between 40% and 60% were about 155 172 square kilometers, mainly in Yunnan,Guangxi, Guangdong, Guizhou, Hainan, Sichuan provinces. The distribution areas were about 329 952.8 square kilometers with ecological similarity between 20% and 40%, mainly in Yunnan, Guangxi, Guangdong, Guizhou, Hainan, Sichuan, Fujian and Chongqing. The climate factors mainly affecting the distribution of Panax notoginseng (Burk.) F. H. Chen were precipitation of warmest quarter, SD of temperature seasonality, altitude, isothermality, coefficient of variation of precipitation seasonality, mean temperature of monthly, precipitation of driest month, reference bulk density of soil and soil texture.

[Analysis of global ecology of Panax notoginseng in suitability and quality]

In this study, the Geographic Information System for Global Medicinal Plants(GMPGIS) was used to assess the global production and ecological adaptation of Panax notoginseng. Based on climate factors and soil types of P. notoginseng from 326 sampling sites, which cover both traditional and current major producing regions, as well as on the results of the ecological similarity computing analysis, we obtained the maximum ecological similarity areas for P. notoginseng worldwide. The results indicated that China was the most suitable ecological and cultivated area globally for P. notoginseng, accounting for more than 70% of the total cultivated area in the world. The United States, Brazil, Portugal, and other 22 countries also had a small amount of potential suitable producing area. China has eight potential suitable producing provinces, including Yunnan, Fujian, Guangxi, Guizhou, etc. The prediction is consistent with the new district of P. notoginseng reported in recent years, which verifies the accuracy of the prediction of GMPGIS. We conducted a literature analysis on resource regeneration and quality ecology on P. notoginseng, and summarized the cultivation, wild tending models, and effects of environmental factors on the quality of P. notoginseng. The results provide scientific basis for selection of P. notoginseng, as well as the introduction, cultivation, and production of P. notoginseng worldwide.

[Effects of stereoscopic cultivation on soil microorganism, enzyme activity and the agronomic characters of Panax notoginseng]

Compartments of soil microorganism and enzymes between stereoscopic cultivation (three storeys) and field cultivation (CK) of Panax notoginseng were carried out, and the effects on P. notoginseng agronomic characters were also studied. Results show that concentration of soil microorganism of stereoscopic cultivation was lower than field cultivation; the activity of soil urea enzyme, saccharase and neutral phosphatase increased from lower storey to upper storey; the activity of soil urea enzyme and saccharase of lower and upper storeys were significantly lower than CK; agronomic characters of stereoscopic cultivated P. notoginsengin were inferior to field cultivation, the middle storey with the best agronomic characters among the three storeys. The correlation analysis showed that fungi, actinomycetes and neutral phosphatase were significantly correlated with P. notoginseng agronomic characters; concentration of soil fungi and bacteria were significantly correlated with the soil relative water content; actinomycete and neutral phosphatase were significantly correlated with soil pH and relative water content, respectively; the activities of soil urea enzyme and saccharase were significantly correlated with the soil daily maximum temperature difference. Inconclusion, The current research shows that the imbalance of soil microorganism and the acutely changing of soil enzyme activity were the main reasons that caused the agronomic characters of stereoscopic cultivated P. notoginseng were worse than field cultivation. Thus improves the concentration of soil microorganism and enzyme activity near to field soil by improving the structure of stereoscopic cultivation is very important. And it was the direction which we are endeavoring that built better soil ecological environment for P. notoginseng of stereoscopic cultivation.

[Research on output and quality of Panax notoginseng and annual change characteristics of N, P and K nutrients of planting soil under stereo-cultivation]

The output and agronomic characters of 3-year-old Panax notoginseng cultured under stereo structure (upper, middle and down layers) were investigated, and the annual change of N, P and K of its planting soil were also studied. Results showed that, compared with field cultured Panax notoginseng, growth vigour and output of stereo-cultivation were significantly lower. But the total production of the 3 layers was 1.6 times of field. The growth vigor and production of P. notoginseng was in the order of upper layer > middle layer > down layer. The content of ginsenoside in rhizome, root tuber and hair root of P. notoginseng was in the order of upper layer > field > middle layer > down layer. Organic matter content and pH of stereo-cultivation soil decreased with the prolonging of planting time, which with the same trend of yield. Organic matter content of stereo-cultivation soil was significantly higher than field, but the pH was significantly lower. Contents of total and available N, P and K in stereo-cultivation soil and field decreased with the prolonging of planting time. The content of N and P were in the order of upper layer > middle layer > yield > down layer, the content of K was in the order of upper layer > middle layer > down layer > yield. Compared with field, the proportion of N and P in the organ of underground (rhizome, root tuber and hair root) of upper layer were increased, while decreased in middle and down layers. Proportion of K in underground decreased significantly of the 3 layers. In conclusion, the agronomic characters and production of stereo-cultivation were significantly lower than that of yield. But the total production of the 3 layers were significantly higher than field of unit area. And the aim of improving land utilization efficiency was achieved. Nutritions in the soil of stereo-cultivation were enough to support the development of P. notoginseng, which was not the cause of weak growth and low production. The absorbing ability of P. notoginseng to N, P and K nutrients was decreased by stereo-cultivation mode. So, improve the growth vigour of P. notoginseng from the perspective of adjusting the stereo-cultivation mode so as to improve the nutrient absorption capacity is the future direction.

[Physiological response and bioaccumulation of Panax notoginseng to cadmium under hydroponic]

The physiological response and bioaccumulation of 2-year-old Panax notoginseng to cadmium stress was investigated under a hydroponic experiment with different cadmium concentrations (0, 2.5, 5, 10 μmol · L(-1)). Result showed that low concentration (2.5 μmol · L(-1)) of cadmium could stimulate the activities of SOD, POD, APX in P. notoginseng, while high concentration (10 μmol · L(-1)) treatment made activities of antioxidant enzyme descended obviously. But, no matter how high the concentration of cadmium was, the activities of CAT were inhibited. The Pn, Tr, Gs in P. notoginseng decreased gradually with the increase of cadmium concentration, however Ci showed a trend from rise to decline. The enrichment coefficients of different parts in P. notoginseng ranked in the order of hair root > root > rhizome > leaf > stem, and all enrichment coefficients decreased with the increase of concentration of cadmium treatments; while the cadmium content in different parts of P. notoginseng and the transport coefficients rose. To sum up, cadmium could affect antioxidant enzyme system and photosynthetic system of P. notoginseng; P. notoginseng had the ability of cadmium enrichment, so we should plant it in suitable place reduce for reducing the absorption of cadmium; and choose medicinal parts properly to lessen cadmium intake.

[Light and temperature and their effects on photosynthesis characteristics of stereoscopic cultivation in Panax notoginseng]

Light intensity, gas temperature, soil temperature and gas exchange parameters were determined of three years old Panax notoginseng planted on different layers seedbed and different location (left, middle, right) of the same layer in greenhouse. Result show that diurnal variation of light intensity, gas temperature and soil temperature showed that upper layer > middle layer > lower layer; different locations of the same layer showed that light intensity of upper layer was not different among different locations; light intensity of middle and lower layer in right and left were the same, and significantly higher than those in the middle position; the gas temperature of each layer all with less different of each location; soil temperature of 12 cm depth is the lowest, and was gradually increased to the upper and lower surface; net photosynthetic efficiency of P. notoginseng showed that upper layer > middle layer > lower layer; there were significant correlation between soil temperature, stomatal conductance, intercellular CO2 concentration and photosynthetic rate were correlated with light intensity significantly; transpiration rates had notable correlation with light intensity and gas temperature. All above indicated that net photosynthesis rate of P. notoginseng was affected by light intensity directly, gas temperature and soil temperature indirectly. Inconclusion, stereoscopic cultivation of P. notoginseng was practicable in present study. The planting quality of P. notoginseng under stereoscopic cultivation could be improved by ameliorate the structure of seedbed to enhance the light intensity of middle and lower layer. Increase the thickness of the seedbed to decrease the temperature difference of soil. Further the management of ventilation facilities of greenhouse to control the gas temperature.

[Study on dynamic change law of N, P and K in Panax notoginseng plant soils with different interval year]

OBJECTIVE

To study effects of different interval year on Panax notoginseng plant soils macro element content.

METHOD

The dynamic change of total N, P, K and available N, P, K in soil from Mabai, Matang, Gumu and Panlong was determined under different planting patterns (new soil, interval 5 years soil and continuous cropping soil).

RESULT

Contents order of soil total N, P and available N, P were interval 5 years soil > continuous cropping soil > new soil. No significant quarter change on soil total N was found, but the other three showed inverted "v" curve, and the peak value appeared on April 2010. Content of soil total K did not change significantly, but the available K content order was new soil > continuous cropping soil > interval 5 years soil, the quarter change was similar as soil available N or P. The soil total N, P, K and available N, P, K were different of the 4 monitoring sites under the 3 interval planting modes. There was a significant correlation between soil total P and available P under all these 3 interval planting modes, but N and K. The propitiation of N-P-K of new soil, interval 5 years soil and continuous cropping soil were 1: 0.4: 2.4, 1: 0.4:1.4, 1:0. 4:2.0, respectively.

CONCLUSION

Continuous cropping pattern induce the accumulation of P, but deficient of K. The imbalance proportion of N, P and K was one of the incentives of continuous cropping induced obstacles. Strengthen the research of optimum proportion of soil N, P and K, and then eliminate continuous cropping obstacles by means of formulated fertilization is the future research direction.

[Comparison of agronomic traits of Panax notoginseng between traditional cultivated fields and new cultivated fields]

OBJECTIVE

In order to provide scientific basis for introduction breeding and production regionalization of Panax notoginseng, the environment of producing area, agronomic traits and medicinal material output were investigated.

METHOD

Using field survey sampling at harvest time, agronomic traits indicators of leaf segment, stem segment and roots segment etc. of commodity P. notoginseng, longitude and latitude, elevation, soil type, landform of producing area were measured and observed.

RESULT

The P. notogiseng cultivation was expanding from traditional area like Wenshang to new areas as Honghe, Kunming, Qujing at large scale. Comparing with traditional cultivated fields, the elevation of new fields, which are red soil of moderate or low mountain slopes and gentle hills between 1 800-2 130 m, increases markedly. The agronomic traits of new cultivated fields such as plant height, stem diameter, the ground and underground biomass were better than those of traditional cultivated fields in varying degree. Furthermore, the root weight, taproot weight, taproot length and other agronomic index augmented more than 20%. Comparison among different cultivated fields showed P. notoginseng of Honghe Shiping Niujie, Kunming Shilin Guishan, Honghe Jiangshui Guanting etc. had better agronomic traits, the plant were thick and tall, the taproot and the top of reed were large, the number of root was more. Inversely, P. notoginseng of Kunming Guandu Xiaoshao, Guangxi Jingxi Lutong, Wenshang Yanshan Jiangna were thin and small. Cluster analysis showed that cultivated fields of P. notoginseng which was across clustered by traditional and new cultivated fields can be divided into three groups, including a high-yielding region insist of three new cultivated fields Honghe Shiping Niujie, Kunming Shilin Guishan, Honghe Jiangshui Guanting and one traditional cultivated field Wenshan Yanshan Jiangna. Correlation analysis indicated that the size and weight of taproot and top of reed were significantly positive correlated with plant height, stem diameter, leaf size, leaf weight and stem weight. Regression analysis pointed out that stem diameter, leaf width, leaf length/width, leaf weight were the main factors affecting the dry weight of taproot, and the main factors influencing the dry weight of top of reed were plant height, petiole, leaf length, leaf width and other agronomic traits.

CONCLUSION

From agronomic traits, P. notoginseng in new cultivated fields were more robust than that in traditional fields, but besides the length of taproot, the difference of rest agronomic traits didn't reach the significant level. It is suggested that, in the west and the north of traditional area, the red soil land of moderate or low mountain slopes and gentle hills where the elevation is between 1 800-2 130 m is suitable for cultivating P. notoginseng. Honghe Shiping Niujie, Honghe Jianshui Guanting, Kuming Shilin Gongshan can be used as vital development area for commodity P. notoginseng.

[Effect of light quality on growth, photosynthesis and effective components of Panax notoginseng]

In order to discover light quality's effects on growth, photosynthesis and effective components content of Panax notoginseng, a pot experiment using 7 light qualities (red, orange, yellow, green, cyan, violet, and blue) was conducted. The growth, photosynthesis and content change of effective components were measured during plant growth. The results showed that light qualities had significant effect on plant growth, red light increased the plant height, while cyan, yellow, violet, and blue lights promoted accumulation of biomass underground, blue and yellow lights increased the photosynthesis, cyan light increased accumulation of ginsenoside Rd, yellow and cyan lights increased total effective components of individual plant.

[Double mulching application for Panax notoginseng growing seedlings]

OBJECTIVE

In order to improve the irrigation for Panax notginseng growing seedlings, different mulching ways were carried out to investigate the effects of double mulching.

METHOD

Field experiment was applied to study soil moisture, soil temperature and bulk density of different mulching ways while the germination rate and seedlings growth also were investigated.

RESULT

Compared with the traditional single mulching with pine leaves or straw, double mulching using plastic film combined with pine leaves or straw could reduce 2/3 volumes of irrigation at the early seedling time Double mulching treatments didn't need to irrigate for 40 days from seeding to germination, and kept soil moisture and temperature steady at whole seedling time about 30% and 9.0-16.6 degrees C, respectively. The steady soil moisture and temperature benefited to resist late spring cold and germinate earlier while kept germination regularly, higher rate and seedlings quality. In contrast, single mulching using pine leaves or straw had poor soil moisture and temperature preserving, needed to irrigate every 12-day, meanwhile dropped the germination and booming time 14 days and 24-26 days, respectively, reduced germination rate about 11.3%-8.7%. However, single pine leaves mulching was better than straw mulching. In addition, though better effects of soil moisture and temperature preserving as well as earlier and higher rate of germination with single plastic films mulching had, some disadvantages had also been observed, such as daily soil temperature changed greatly, seedling bed soil hardened easily, more moss and weeds resulted difficulty in later management.

CONCLUSION

To the purpose of saving water and labor as well as getting higher germination rate and seedlings quality, double mulching using plastic films combined pine leaves at the early time and single mulching removing plastic films at the later time is suggested to apply in the growing seedlings of P. notoginseng.

[Study on dynamic change of middle and micro element in Panax notoginseng plant soils with different interval year]

OBJECTIVE

To study effects of different interval year on Panax notoginseng plant soils middle and micro element content.

METHOD

The dynamic change of Ca, Mg, Mn, Cu, Zn, B from Mabai, Matang, Gumu and Panlong were determined under different planting patterns (new soil, interval 5 years soil and continuous cropping soil).

RESULT

All the micro elements (except Ca, Mg) of interval 5 years soil and continuous cropping soil were significantly higher than those of new soil. All the middle and micro elements (except B) of interval 5 years soil were significantly higher than those of the continuous cropping soil. Planting patterns had remarkable influence on the content of Mn, Cu, B, but not Zn Ca, Mg. Cu, Ca under the 3 planting patterns, and Zn under the continuous cropping pattern did not show significant quarter changes. B content increased with the elongation of implantation time. Zn in new soil and interval 5 years also increased with prolonging of planted time. Mg, Mn and Cu content reached to peak value on April next year, and reached to minimum on the end of this experiment. Compared with new soil, the proportion of Mn, Cu in total elements increased by 29%, 114%, Mg, B decreased by 18%, 38%, Zn and Ca changed slightly of interval 5 years soils; In continuous cropping soil, Mn, Cu and B increased by 50%, 120%, 22%, respectively, but Zn, Ca, Mg had no significant change.

CONCLUSION

Continuous cropping pattern could not induce the deficient of soil middle and micro elements, and thereafter might not result in continuous cropping obstacles. But the imbalance proportional of soil middle and micro elements in P. notoginseng plant soils may be one of the main reasons for continuous cropping obstacles.

[Allelopathic effects of aqueous extracts from Panax notoginseng on three maize varieties (Zea mays)]

It has been showed that there were obvious obstacle effects of Panax notoginseng replanting. Crop rotation was the main effective technique to overcome the obstacle. To find a reasonable crop rotation system for P. notoginseng, aqueous extracts from root, stem and leaf of P. notoginseng were analyzed for allelopathic effect on three maize varieties (which are often grown in regions where P. notoginseng grown). The main results were as follows: (1) Allelopathic effect of P. notoginseng stem and leaf extracts on the three other tested plants was stronger than that of root extracts; (2) Corn was more vulnerable to the effects of allelochemicals at seedling stage than at germination stage, and the corn root was more sensitive than aerial part to allelochemicals; (3) Lusan No. 3 and Yunrui No. 1 showed resistance to P. notoginseng allelopathy, with respective comprehensive sensitivity indexes (M3) of - 0.089 3 and -0.159 2, while Bainuo No. 1 is sensitive at M3 = -0.261 0. It then can be concluded that Lusan No. 3 and Yunrui No. 1 may be an alternative rotation plants for overcoming P. notoginseng continuous cropping obstacle.

[Chinese Sanqi industry status and development countermeasures]

Sanqi (Panax notoginseng) is a valuable unique herb, and is also one of the very fast developed varieties of traditional Chinese medicines in recent years with increasing role in traditional Chinese medicine industry. This paper summarized the main experience, industry development and present situation, pointed out the main problems existing in the industry development. On this basis, we put forward the targets and measures for the development of the Sanqi industry in to provide decision-making reference for the sustainable development of the Sanqi industry in China.

[Different proportion of potassium chloride and potassium sulphate application on cultivation of Panax notoginseng]

In order to make sure whether Panax notoginseng is sensitive to chloridion and guide fertilization in planting of P. notoginseng, the effects of the different proportion of potassium chloride (KCl) and potassium sulfate (K2SO4) on the yield, quality of P. notoginseng were studied. The results showed that K fertilizer significantly improved the growth of P. notoginseng and increased the biomass per plant or per pot and the content of N, P, K and the content of saponin. In cases of conditions such as potassium, and the effects of K2SO4 on increasing the petiole length, leaf size, rhizome length, root length, and content and accumulation of Ginsenoside Rg1 were better than those of KCl. While compared with K2SO4, KCl was more conducive to augmenting height, root width, the biomass of shoot, rhizome, root and the content of Ginsenoside Rb1 and Rd. There was not remarkable difference in agronomic characters, biomass and the content of N, P, K among KCl, K2SO4 and the combination of KCl and K2SO4. However, the content of saponin of the treatment with combination of KCl and K2SO4 was significant higher than that of single KCl or K2SO4 treatments. K fertilizer significantly increased yield and the content of saponins. And P. notoginseng was not sensitive to chloridion. KCl increased the yield and the content of saponins of P. notoginseng as well as K2SO4, and the combination treatment was superior to single treatment. It is recommended that the KCl should be adopted in production, to reduce the cost of potash fertilizer.

Arsenic stabilization by zero-valent iron, bauxite residue, and zeolite at a contaminated site planting Panax notoginseng

Panax notoginseng (Burk.) F.H. Chen, a rare traditional Chinese medicinal herb, is a widely used phytomedicine used all over the world. In recent years, the arsenic contamination of the herb and its relative products becomes a serious problem due to elevated soil As concentration. This study aimed to evaluate the effects of different types and dosages of amendments on As stabilization in soil and its uptake by P. notoginseng. Results showed that comparing to control treatment, the As concentrations of P. notoginseng declined by 49-63%, 43-61% and 52-66% in 0.25% zero-valent iron (Fe(0)), 0.5% bauxite residue, and 1% zeolite treatment, respectively; whereas the biomasses were elevated by 62-116%, 45-152% and 114-265%, respectively. The As(III) proportions of P. notoginseng increased by 8%, 9%, and 8%, and the transfer factors of As from root to shoot increased by 37%, 42% and 84% in the optimal treatments of Fe(0), bauxite residue, and zeolite. For soil As, all the three amendments could transform the non-specifically adsorbed As fraction to hydrous oxides Fe/Al fractions (by Fe(0) and red mud) or specifically adsorbed As fraction (by zeolite), therefore reduced the bioavailability of soil As. With a comprehensive consideration of stabilization efficiency, plant growth, environmental influence, and cost, Fe(0) appeared to be the best amendment, and zeolite could also be a good choice. In conclusion, this study was of significance in developing As contamination control in P. notoginseng planting areas, and even other areas for medicinal herb growing.

[Analysis on influential factors of Chinese medicinal herb growers' willingness to use green pesticides: evidence on Panax notoginseng production areas in Wenshan, Yunnan province]

The purpose of the article is to apply a binary logistic model to analyze the major factors, which influence Chinese medicinal herb growers' willingness to use green pesticides by using survey data collected in Wenshan, Yunnan Province. The results indicate that, output per capita, average pesticide cost per mu, cognition of pesticide residues, expectations on Panax notoginseng prices, cognition of pesticides' effect of pests control, cognition of P. notoginseng prices of low pesticide residues have a significant influence on growers' willingness to use green pesticides. According to the analysis above, some proposals for enhancing Chinese medicinal herb growers' willingness to use green pesticides are put forward, such as, moving toward the intensive planting systems, fetching down the pieces of green pesticides, emphasizing and propagating the advantages of green pesticides, keeping the prices of Chinese medicinal herb running at steady rates.

[Dynamics of ginsenoside biosynthesis in suspension culture of Panax notoginseng]

OBJECTIVE

To study the dynamics of ginsenoside biosynthesis in suspension culture of Panax notoginseng.

METHODS

The calli of Panax notoginseng were suspended in liquid medium for 40 d, and the changes of ginsenosides were determined by HPLC method.

RESULTS

Cell growth was slow in suspension culture, but the contents of six ginsenosides varied with different culture time. The contents of four ginsenosides Rg1, Re, Rh1 and Rb1 showed the increases from about 3.63 to 9.72 mg/g, 2.34 to 7.02 mg/g, 0.42 to 2.37 mg/g and 0.24 to 1.86 mg/g, respectively during 25 and 30 days of the culture. Rh2 and F1 had no obvious change. Such results indicated that the protopanaxatriol saponions (Rg1, Re and Rh1) increased significantly during the growth phase.

CONCLUSION

When the callus is cultured for 25 days, the maximum yield of total saponins content is up to 20.58 mg/g,mainly of the protopanaxatriol saponins.

[Effects of balanced fertilization and soil amendment on growth and yield of sanqi in continuous cropping]

OBJECTIVE

To explore the solution of continuous cropping obstacle of Panax notoginseng.

METHOD

The effects of balanced fertilization and soil amendment on the emergence rate, survival rate, growth and yield of P. notoginseng were studied with a pot culture experiment in 3-year-interval continuous cropping soil.

RESULT

The result showed that the content of total N, total P, available N, available P and other available components in continuous cropping soil were higher than those in fresh soil while available K and the rate of K/N were declined, and available Cu and some other micro elements were lack. The way of balanced fertilization "low N + fused calcium-magnesium-phosphate fertilizer + high K + lime + micro elements" would significantly enhance the rate of survival, biomass and yield. It also promoted the growth of P. notoginseng in continuous cropping. The bagasse could relieve the continuous cropping obstacle obviously, the survival rate was improved for 31.6% and the yield of medicinal materials was 19.5%. The fly ash had also some effect in relieving the continuous cropping obstacle.

CONCLUSION

The overall results suggested that the adequate fertilization plan is the applying lime, reducing N, applying calcium-magnesium-phosphate fertilizer, improving K and supplying mircoelement as well as applying bagasse to resolve the problem of continuous cropping obstacle of P. notoginseng.

Arsenic accumulation and resistance mechanism in Panax notoginseng, a traditional rare medicinal herb

Panax notoginseng, a traditional rare Chinese medicinal herb, was recently found to bring health risk to consumers, mainly because soil in its major plantation area was contaminated by arsenic (As). We investigated the effect of soil As pollution on the growth and As uptake of pot-cultured P. notoginseng, and the associated mechanisms of As stressed response. Results showed that, comparing with P. notoginseng growing in a low-As soil, the root, stem, and leaf biomasses of those growing in a high-As soil significantly reduced by 0.75, 0.09 and 0.21 g seedling(-1), respectively. Arsenic concentrations in roots, stems and leaves of the seedlings growing in high-As soil were 22, 15 and 3 times higher than those growing in low-As soil, respectively. Regardless of the soil As concentration, As existed in plants mainly as As(III), suggesting that the reduction of As(V) is a key step in As metabolism. Arsenic was distributed primarily in cell walls (51.7% for plants growing in the low-As soil, and 51.5% in the high-As soil), followed by cytoplasm supernatant, with cell organelles containing the least As. Compared with plants growing in the low-As soil, those in the high-As soil had increased superoxide dismutase and peroxidase activities in their roots, stems, and leaves, which would be associate with improving the resistance of P. notoginseng to As stress. The results suggest that there exists some special mechanisms of As-tolerance in P. notoginseng and the study is of significance in developing measures to reduce As in the herb.

[Status and prospective on nutritional physiology and fertilization of Panax notoginseng]

Sanqi, Panax notoginseng, is a famous traditional Chinese herb, which has more than 400 years cultivation history in China. This paper has reviewed the studies on the suitable growing soil conditions for Sanqi, mineral nutrition effects on Sanqi, and the effects of nutrients uptake on the yield and quality of Sanqi by applying fertilizer. Thereafter, research needed to be put further efforts in the future has raised for discussion, and outlined the following topics for further research like the mechanism of mineral nutrition, methods of nutrients deficiency diagnosis on site, suitable cultivated soil grading special fertizer development, disease resistance, and fertilization recommended by soil testing.

Identification and characterization of differentially expressed genes involved in pharmacological activities of roots of Panax notoginseng during plant growth

Panax notoginseng is a highly valued Chinese medicinal herb. To understand the molecular mechanism of the much higher pharmacological activities of roots of 3-year-old plants over 1-year-old ones,two cDNA libraries were constructed using the suppression subtractive hybridization (SSH) method. Positive cDNA clones from each of the two libraries were randomly selected for dot-blotting analysis. A total of 110 genes were highly expressed in 3-year-old roots and 80 genes in 1-year-old roots. Of these, 87 cDNA fragments were sequenced, assembled, and compared with sequences in GenBank, and 81 individual cDNAs were identified. These cDNAs were the first expressed sequence tags of P. notoginseng in GenBank. The result of reverse transcription PCR analysis of six genes was consistent with that of the dot-blot analysis. The global gene expression profile showed that there were significant differences between 1- and 3-year-old roots of P. notoginseng plants. Some important structural and regulatory genes which may be involved in isoprenoid biosynthesis were found to be over-expressed in 3-year-old roots, such as genes encoding 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphat-synthase (IspG-protein), multi-copper oxidase type I family protein, NADH flavin oxidoreductase, lipase and aconitase.

[Adventitious root induction and in vitro culture of Panax notoginseng]

OBJECTIVE

To investigate the induction and culture of adventitious root of Panax notoginseng.

METHOD

Three ways, induction from the explants of three-year-old P. notoginseng. The explants of regenerated shoots and calluses, were used to induce adventitious roots. The effects of 2, 4-dichlorophenoxyacetic acid, indole-3-butyric acid and naphthylacetic acid on adventitious root induction were investigated respectively. The effects of four modes of separating adventitious roots from the parent tissues on culture in vitro were compared.

RESULT

Adventitious roots were successfully induced by three methods, of which the young flower bud callus was the best material for the induction of adventitious root. Indole-3-butyric acid possessed the strongest potency for induction. The liquid culture system was established by continuous culture of adventitious roots together with their parent tissues before separated.

CONCLUSION

The acquisition and culture in vitro in liquid culture system of adventitious roots of P. notoginseng lay a foundation for the next investigation.