A Study on the Biological Effects of Laser-induced Mutation on Fibrous Roots of Yellow Skin Onion

[ Objective] This study aimed to investigate the biological effects of laser-induced mutation on fibrous roots of yellow skin onion. [ Method] Wet seeds of two yellow skin onion cultivars were irradiated by CO2 laser and He-Ne laser at three dosage levels separately. A randomized complete block design with three replications was adopted. The biological effects of laser-induced mutation on fibrous roots of Ll-generation yellow skin onion were investigated with biostatistics and physiological and biochemical methods. [Result] Significant variations in the biological effects caused by various laser treatments were observed in the length, quantity, fresh weight and activity of onion fibrous roots. Specifically, the variation in fibrous root length induced by different types of laser reached 5% significance level; significant variation was observed in fibrous roots of different onion cultivars induced by laser, while the variation among each treatment did not reach 5% sig- nifieance level ; the variation in fibrous root quantity induced by different dosage levels of laser reached 5% significance level ; laser radiation showed stimulating effect on root activity of onion. [ Conclusion] This study provided reference for laser-induced breeding of yellow skin onion.

Saponins Content in Fibrous Roots of Pseudostellaria heterophylla and Optimization of the SEP Extraction Technology

[Objectives]To explore the saponins resources in fibrous roots of Pseudostellaria heterophylla and optimize the SEP technology for extracting saponins.[Methods]Saponins contents in fibrous roots and root tubers of P.heterophylla were compared;with the fibrous roots as host materials,this experiment applied Box-Behnken design to analyze the influence of steam pressure,maintenance pressure time,moisture content of host materials on the content of saponins extracts.[Results]Saponins content was higher in fibrous roots than in tuberous roots of P.heterophylla;the response surface optimization showed that SEP(steam explosion pretreatment)promoted the contents of saponins and extracts in fibrous roots,and the optimal extracting conditions were stream pressure 1.50 Mpa,maintenance pressure time 54 s,and moisture content of host materials 30%.Under this extracting conditions,the verification value of saponins content experiment was 0.441%,36.53%higher than the untreated control group.[Conclusions]This research offered a new method of exploring saponins resources from fibrous roots of P.heterophylla,and provided a reference for developing new medicinal parts of P.heterophylla.

Optimization of Enzymatic Extraction Process of Polysaccharides from Pseudostellaria heterophylla Fibrous Roots by Response Surface Methodology and Its Pilot Application

[Objectives]To study and optimize the process conditions of enzymatic hydrolysis technology for extracting polysaccharides from Pseudostellaria heterophylla fibrous roots and its application in workshop pilot tests.[Methods]P.heterophylla fibrous roots were taken as the matrix material,and Box Behnken design was used to analyze the extraction time,composite enzyme addition amount,and liquid-solid ratio for response surface optimization experiments,and then applied to the pilot extraction of P.heterophylla fibrous roots.[Results]Response surface analysis showed that all factors had a significant impact on the experimental indicators.The optimal extraction process conditions for polysaccharides from P.heterophylla fibrous roots were extraction time of 2.7 h,compound enzyme addition of 2.5%,and liquid-solid ratio of 32.The yield of polysaccharides from P.heterophylla fibrous roots was 4.83%.The water extraction process of P.heterophylla fibrous roots extraction pilot was used as the control group for response surface optimization of the pilot experiment.The optimization results showed that the extraction time was 3 h,the amount of composite enzyme added was 2.5%,and the liquid-solid ratio was 28.The polysaccharide yield was 4.75%,an increase of 4.63%compared to the control group.[Conclusions]This paper could provide feasibility for the innovation of enzy-matic hydrolysis technology for P.heterophylla fibrous roots and its workshop pilot practice application,as well as a reference for the industrial application of its medicinal resources.

Dynamic Microwave-Assisted Extraction of Total Ginsenosides from Ginseng Fibrous Roots

A dynamic microwave-assisted extraction（DMAE） method is established for the extraction of total ginsenosides from ginseng fibrous roots. The extraction process has been simulated and its main affection factors（liquid/solid ratio K of solvent to ginseng powders（V/m）, irradiation time, irradiation temperature, extracting solution concentration, flow rate of solvent and microwave power） have been optimized by response surface methodology（RSM）. The optimum conditions of extraction are the liquid/solid ratio of 270 m L/g, the extraction temperature of 75 ℃, the extraction time of 35 min, ethanol concentration of 70%（V/V）, the solvent flow rate of 1.3 m L/min, and the microwave power of 500 W. The yield of ginsenosides obtained by the proposed DAME method is（15.0±0.7） %, which is well agreement with the yield predicted by the model. Compared with static microwave-assisted extraction, DMAE has a higher extraction yield and can avoid the degradation of ginsenoside.

Effects of Different Concentrations of Radix pseudostellariae Fibrous Root Extracts on Serum Cytokines in Mice and Their Correlation Analysis

To investigate the effects of Radix pseudostellariae fibrous root extracts(RPFRE) on serum cytokines in normal and immunosuppressed mice and the correlation between indexes, KM male mice were randomly divided into four groups, which were given 0(control), 0.1, 0.2, 0.4 g/kg RPFRE by gavage. The levels of IL-2, IL-4, IL-6, and IFN-γ in the serum of mice were measured 14 d after gavage. On the 15day, the remaining mice in the experimental group were intraperitoneally injected with cyclophosphamide(CY), and samples were collected on the 18day to measure serum cytokines levels. The results showed that RPFRE improved the serum cytokine level in normal mice. 0.1 g/kg RPFRE significantly increased the content of IL-2and IFN-γ(P<0.05), while 0.4 g/kg RPFRE significantly increased the content of IL-4 and IL-6(P<0.05). Correlation analysis showed that serum cytokines IL-4 and IL-6 in normal mice had an extremely significant positive correlation with RPFRE concentration(P<0.01), IL-2 had a significant or extremely significant positive correlation with IL-4, IL-6, and IFN-γ(P<0.01or P<0.05), and IL-4 had an extremely significant positive correlation with IL-6(P<0.01). After CY injection, serum cytokine levels in mice decreased and immune function was inhibited. Compared with the control group, the experimental group recovered the level of cytokines to some extent. 0.1 g/kg RPFRE significantly increased the content of IL-2 in immunosuppressed mice(P<0.05), and 0.4 g/kg RPFRE significantly increased the content of IL-4, IL-6, and IFN-γ in immunosuppressed mice(P<0.05). Correlation analysis showed that the serum cytokines in immunosuppressed mice were significantly positively correlated with RPFRE concentration(P<0.01), and there was a certain dose dependence. Moreover, the correlation coefficient between IL-2 and IL-4, IL-6, and IFN-γ, IL-4 and IL-6, and IL-6 and IFN-γ reached an extremely significant level(P<0.01). To sum up, RPFRE could improve the serum cytokines level of mice, promote the secretion of cytokines, and have a certain immune protective effect. There was a significant positive correlation between the RPFRE concentration and the serum cytokines in mice, which provided basic data support for the further study of RPFRE immune function.

Immunoprotection Effects of Radix Pseudostellariae Fibrous Root Extraction (RPFRE) on Mice and Its Relationship with Antioxidant Function

[Objective] The paper was to explore the immunoprotection effects of Radix Pseudostellariae fibrous root extraction(RPFRE) on experi-mental mice and its relationship with antioxidant function. [Method] KM male mice were randomly divided into 4 groups based on RPFRE gradient concentration, and the immune function indexes and antioxidant indexes of mice were determined at 14 d post intragastric administration of RPFRE.The remaining mice in the experimental group were intraperitoneally injected with cyclophosphamide(CY) from the 15^(th) to 17^(th) day, and samples were collected to determine the above indexes on the 18^(th) day. [Result] Intragastric administration of RPFRE for 14 d improved the spleen index,thymus index, T/B cell stimulation index and total antioxidant capacity(T-AOC) of normal mice, and extremely increased the thymus index and TAOC(P<0.01). The T-AOC had extremely positive correlation with the spleen index, thymus index and B cell stimulation index( P<0.01), and had significantly positive correlation with the T cell stimulation index(P<0.05). From the 15^(th) to 17^(th) day of the experiment, the immune function indexes and antioxidant indexes of mice decreased and the malondialdehyde(MDA) content increased. The experimental groups of 0.1, 0.2 and 0.4 g/kg RPFRE promoted the immunoprotection and antioxidant effect of mice. RPFRE concentration had extremely positive correlation with 4 indexes of immune function and antioxidant indexes T-AOC and SOD(P<0.01), but had extremely negative correlation with MDA(P<0.01). There was a significantly positive correlation between immune function indexes and antioxidant indexes of mice after CY intervention( P<0.05 or P<0.01). [Conclusion] RPFRE can improve the immune function indexes and antioxidant indexes of normal mice and immunosuppressed mice and has immunopro-tection effect on immunosuppressed mice, and there is a significant correlation between immune function indexes and antioxidant indexes of mice.

Effect of Root Architecture on Structural Stability and Erodibility of Topsoils during Concentrated Flow in Hilly Loess Plateau

Traditional vegetation techniques for the control of concentrated flow erosion are widely recognized, whereas only a few studies have experimentally investigated the impacts of belowground roots on the erodibility of topsoils in semi-arid areas. To quantify the effects of root architectures on soil erodibility and its relevant structural properties, simulated flow experiments were conducted at six-week intervals from 18 July to 20 October in 2012 in the hilly Loess Plateau. Five treatments were: 1) bare(control), 2) purple alfalfa(Medicago sativa), representing tap roots(T), 3) switchgrass(Panicum virgatum), representing fibrous roots(F), 4) purple alfalfa and switchgrass, representing both tap and fibrous roots(T + F), and 5) natural recovery(N). For each treatment, soil structural properties and root characteristics were measured at an interval of six weeks. Soil anti-scouribility was calculated. Results showed that grass planting slightly reduced soil bulk density, but increased soil aggregate content by 19.1%, 10.6%, 28.5%, and 41.2% in the treatments T, F, T + F, and N, respectively. Soil shear strength(cohesion and angle of internal friction(φ)) significantly increased after the grass was planted. As roots grew, soil cohesion increased by 115.2%–135.5%, while soil disintegration rate decreased by 39.0%–58.1% in the 21 th week compared with the recorded value in the 9th week. Meanwhile, root density and root surface area density increased by 64.0%–104.7% and 75.9%–157.1%, respectively. No significant differences in soil anti-scouribility were observed between the treatments of T and F or of T + F and N, but the treatments of T + F and N performed more effectively than T or F treatment alone in retarding concentrated flow. Soil aggregation and root surface-area density explained the observed soil anti-scouribility during concentrated flow well for the different treatments. This result proved that the restoration of natural vegetation might be the most appropriate strategy in soil reinforcement in the hilly Loess Plateau.

In-situ Horizontal Extrusion Test of Herbaceous Root-Soil with Different Root Types

The influence of different types of roots on the soil is complex and still remains unclear.Four in-situ extrusion tests were conducted on two types of root systems,namely fibrous and tap root system,for three plants,Eleusine indica,Potentilla anserine,and Artemisia argyi,according to the classification in Botany,and the thrust-displacement curves and failure patterns of different samples were analysed by comparison to fill the aforementioned gap.Results reveal that the roots can reduce the characteristics of soil brittleness and enhance its capability to resist large deformation,and different root types contribute different effects to the strain-hardening behavior of the root-soil mass.The contribution of the fibrous root system to strength is limited,whilst the tap root system substantially enhances strength and stiffness.Results of failure patterns show that fibrous and tap root systems affect soil solidification and surface cracking reduction.However,the effect of the tap root system depends on the composition of lateral and tap roots:long and rich lateral roots are effective for resisting the creation of cracks,but thick tap roots with few and thin lateral roots may lead to several surface cracks.

Liposoluble chemical constituents from the fibrous root of Ophiopogonjaponicas

We investigated the chemical constituents of the fibrous root of Ophiopogon japonicus and their cytotoxicities against Hela and Hep2 cells.Ten compounds were purified by various chromatographic techniques.Their structures were identified as 2 - hydroxylophiopogonone A（1）,5,8-dimethoxy-6-methyl-7-hydroxy-3-（2 -hydroxy-4 -methoxybenzyl） chroman-4-one（2）,5,7- dihydroxy-6,8-dimethyl-3-（4 -hydroxybenzyl） chroman-4-one（3）,7,4 -dihydroxy-5-methoxyflavanone（4）,N-trans-coumaroyltyramine （5）,N-trans-coumaroyloctopamine（6）, N-trans-feruloyltyramine （7）, 4-hydroxycinnamic acid （8）, caffeic acid （9）, and ferulic acid （10） on the basis of spectroscopic analyses. Compounds 4, 6, 7, 9, 10 were obtained from this genus for the first time. The cytotoxic activities of 1, 2, 4, 5, 6, 7, 9 and 10 against Hela and Hep2 cells are described.

Growth Promotion Effects of Bacillus subtilis on Bletilla striata Seedlings

Objective:The objective of the study is to study the growth promotion effects of Bacillus subtilis inoculants on the growth of Bletilla striata seedlings.Methods:Various concentrations(1/10×,1/50×,1/100×,and 1/500×dilutions)of B.subtilis inoculants were applied on the B.striata seedlings.Plant height,base diameter,leaf length,leaf width,relative chlorophyll content,tuber diameter,average fibrous root length,number of fibrous roots,and fresh weight were measured after incubation for 50 days.Results:Treatments with different concentrations of B.subtilis significantly increased the number of fibrous roots of the B.striata seedlings and promoted root elongation,and a higher concentration(1/10×dilution)is associated with more significant promotion effects.B.striata seedlings treated with different concentrations of B.subtilis all showed an increase of relative chlorophyll contents in leaves with the increasing inoculant concentration.Only B.subtilis inoculant at a high concentration(1/10×dilution)significantly promoted the plant height and base diameter of B.striata seedlings.The application of B.subtilis did not significantly promote the tuber diameter and fresh weight of B.striata seedlings.Principal component analysis confirmed the maximum growth promotion by B.subtilis inoculant in 1/10×dilution than the other treatments.Conclusions:The application of B.subtilis can increase the relative chlorophyll content,promote growth and development of roots,and increase plant height and base diameter of B.striata seedlings.Therefore,B.subtilis has significant growth promotion effects on B.striata seedlings.These findings provide theoretical basis for the ecological cultivation of B.striata.

Evaluation of high yielding soybean germplasm under water limitation

Limited information is available for soybean root traits and their plasticity under drought stress. To date, no studies have focused on examining diverse soybean germ- plasm for regulation of shoot and root response under water limited conditions across varying soil types. In this study, 17 genetically diverse soybean germplasm lines were selected to study root response to water limited conditions in clay （trial 1） and sandy soil （trial 2） in two target environments. Physiological data on shoot traits was measured at multiple crop stages ranging from early vegetative to pod filling. The phenotypic root traits, and biomass accumulation data are collected at pod filling stage. In trial 1, the number of lateral roots and forks were positively correlated with plot yield under water limitation and in trial 2, lateral root thickness was positively correlated with the hill plot yield. Plant Introduction （PI） 578477A and 088444 were found to have higher later root number and forks in clay soil with higher yield under water limitation, in sandy soil, P1458o2o was found to have a thicker lateral root system and higher yield under water limitation. The genotypes identified in this study could be used to enhance drought tolerance of elite soybean cultivars through improved root traits specific to target environments.