Green synthesis,characterization,acaricidal,larvacidal,and repellent activities of copper nanoparticles of Astragalus sinicus against Hyalomma anatolicum

Objective:To green synthesize and characterize copper nanoparticles(Cu NPs)using Astragalus sinicus,as well as evaluate the acaricidal,larvacidal,and repellent activities of Cu NPs against Hyalomma anatolicum(H.anatolicum),one of the most prevalent ticks infesting cattle in Saudi Arabia.Methods:Cu NPs were green synthesized by adding the Astragalus sinicus extract to a copper sulfate solution.The acaricidal,larvicidal,and repellent activities of Cu NPs against H.anatolicum were assessed via the adult immersion test,the larval packet test,and the vertical movement behavior of tick larvae,respectively.The effects of Cu NPs on acetylcholinesterase as well as oxidative enzyme activities were examined.Results:The green synthesized Cu NPs displayed a spherical form with a size range of 15-75 nm.After exposure of adult H.anatolicum to different concentrations of Cu NPs,the viability rate of adult H.anatolicum and the mean number,weight,and hatchability of eggs were noticeably reduced,in comparison to the control group(P<0.001).In addition,the viability rate of larvae considerably declined(P<0.001)with the LC_(50)and LC_(90)values of 11.30 and 20.34μg/m L,respectively.The maximum repellent activity of Cu NPs was observed at 50,100,and 200μg/m L with complete repellent activity after 60,120,and 180 min of exposure,respectively.Cu NPs,mainly at 1/2 LC_(50)and LC_(50)concentrations,markedly suppressed the acetylcholinesterase activity of the larval stage of H.anatolicum(P<0.001).Moreover,Cu NPs,mainly at LC_(50)dose,significantly elevated malondialdehyde level while declining glutathione-S-transferase level in H.anatolicum larvae(P<0.001).Conclusions:Cu NPs show potent acaricidal,larvicidal,and repellent activities against adults and larvae of H.anatolicum.However,further studies must be performed to clarify the precise mechanisms and the efficacy of Cu NPs in practical use.

Adaptability Comparison of Chinese Milk Vetch (Astragalus sinicus) Varieties for Double-rice Cropping System in Hunan

Five Chinese milk vetch（Astragalus sinicus） varieties were selected to make a comparison in order to screen effective varieties which could suit for the double-rice cropping system of Hunan Province. The results showed that the growth period of Xiangzi 2 is shorter than that of Xiangfei 2, Xiangfei 3 and Yujiangdaye,and is similar to that of Xinyang Chinese milk vetch. The full-bloom stage of Xiangzi 2 is also similar to Xinyang variety and obviously earlier than that of the other three varieties. The fresh grass yield of Xiangzi 2 in full-bloom stage is 23 842.5kg/hm^2, which increases by 39.9% compared with Xinyang variety. Nitrogen content in the fresh grass of Xiangzi 2 is higher than that of the other four varieties. In conclusion, Xiangzi 2 is an extremely early-blossoming and early-maturing Chinese milk vetch variety with moderate fresh grass yield, high nutrient contents, stable characters and wide adaptability. So, Xiangzi 2 is suitable for planting in double-rice cropping region in Hunan Province and other same latitude regions which have similar ecological conditions.

Genetic Variability of Astragalus sinicus L. Based on ISSR Markers

Genetic relationships among 22 accessions of Astragalus sinicus L. col ect-ed from different provinces of China were analyzed by inter-simple sequence repeat （ISSR） markers. The results showed that 10 highly reproducible ISSR fragments a-mong 40 primers were screened. Using these primers, a total of 684 ISSR frag-ments from 500 to 3 000 bp were amplified, and 59.2% of them showed polymor-phic by unweighted pair-group method with arithmetic （UPGMA） analysis. It revealed that the 22 accessions had a similarity range from 0.63 to 0.95, and existed biolog-ical diversities. Based on cluster and principal coordinate analyses, al accessions could be divided into four distinct groups.

Effects of Ploughing Astragalus sinicus at Maturity Stage on Rice Yield and Soil Properties of Paddy Field

[Objective] The effects of ploughing Astragalus sinicus at maturity stage as green manure on paddy soil properties were studied to provide references for ad- vancing the green manure production and field sustainable development. [Methods] A three-year field positioning experiment was carried out. In the first year, five differ- ent levels （0, 2.81, 5.61, 8.42, 11.23 t/hm~） of Astragalus sinicus ploughed at matu- rity stage were designed. And in the next two years, the amounts of ploughed As- tragalus sinicus at maturity stage were based on the natural growth amounts of As- tragalus sinicus at maturity stage of the former year in each plot field. The yields of Astragalus sinicus at maturity stage were estimated and ploughed directly before rice transplanting. Rice yield, soil nutrients, biological properties and water-stable aggre- gates of paddy fields were measured as well. [Results] The effective panicles and rice yields increased significantly after ploughing Astragalus sinicus at maturity stage. Meanwhile, the organic acid content in paddy field increased and the activities of soil phosphatases, invertase and catalase were higher. The soil dissolved organic carbon also increased with the increasing application of green manure. However, excess amount of green manure inhibited the soil microbial biomass carbon content. The macro aggregates and micro aggregates gathered to middle aggregates. [Conclusion] As green manure, the use of Astragalus sinicus at maturity stage could improve soil physiochemical and biological properties, improve soil fertility and increase rice yield significantly. But the ploughing amount of Astragalus sinicus at maturity stage before rice transplanting should be less than 8.42 t/hm2 （dry weight.

Vacuolar phosphate transporters account for variation in phosphate accumulation in Astragalus sinicus cultivars

Astragalus sinicus is a commonly used legume green manure that fixes atmospheric N2 and accumulates mineral nutrients and organic substances that are beneficial to soils and subsequent crops.However,little is known about genotypic variation in,and molecular mechanisms of,Pi(phosphate)uptake and storage in A.sinicus.We recorded the morphological responses of six A.sinicus cultivars from four regions of China to external Pi application and measured their Pi accumulation.We identified full-length transcripts of Pi-signaling and Pi-homeostasis regulators by sequencing and measured the expression level of these genes by qRT-PCR.The major components in Pi signaling and Pi homeostasis were largely conserved between A.sinicus and the model species rice and Arabidopsis.Different A.sinicus varieties responded differently to low-phosphorus(P)stress,and their Pi accumulation was positively correlated with the expression of vacuolar Pi influx gene(SYG1/PHO81/XPR1-MAJOR FACILITATOR SUPERFAMILY(SPX-MFS)-TYPE PROTEIN)AsSPXMFS2 and negatively correlated with the expression of the vacuolar Pi efflux gene(VACUOLAR Pi EFFLUX TRANSPORTER)AsVPE1.We identified key Pi-signaling and Pihomeostasis regulators in A.sinicus.The expression of vacuolar Pi transporter genes could be used as an index to select A.sinicus accessions with high Pi accumulation.

The chromosome-level genome assembly of Astragalus sinicus and comparative genomic analyses provide new resources and insights for understanding legume-rhizobial interactions

The legume species Astragalus sinicus(Chinese milk vetch[CMV])has been widely cultivated for centuries in southern China as one of the most important green manures/cover crops for improving rice productivity and preventing soil degeneration.In this study,we generated the first chromosome-scale reference genome of CMV by combining PacBio and Illumina sequencing with high-throughput chromatin conformation capture(Hi-C)technology.The CMV genome was 595.52 Mb in length,with a contig N50 size of 1.50 Mb.Long terminal repeats(LTRs)had been amplified and contributed to genome size expansion in CMV.CMV has undergone two whole-genome duplication(WGD)events,and the genes retained after the WGD shared by Papilionoideae species shaped the rhizobial symbiosis and the hormonal regulation of nodulation.The chalcone synthase(CHS)gene family was expanded and was expressed primarily in the roots of CMV.Intriguingly,we found that resistance genes were more highly expressed in roots than in nodules of legume species,suggesting that their expression may be increased to bolster plant immunity in roots to cope with pathogen infection in legumes.Our work sheds light on the genetic basis of nodulation and symbiosis in CMV and provides a benchmark for accelerating genetic research and molecular breeding in the future.

广西地方紫云英种质资源收集及表型多样性评价

以农业农村部“第三次全国农作物种质资源普查与收集行动”为契机,开展了广西壮族自治区紫云英(Astragalus sinicus L.)种质资源的考察收集与评价鉴定。结果表明,收集到的58份地方资源主要分布在桂东北以及0~400 m的中低海拔地区。12项农艺性状表型分析显示其遗传多样性丰富;主成分分析将12个农艺性状分为3个主成分,分别为种子产量、生物产量及生育期特征,累计贡献率达72.089%;通过加权平均计算得出综合排名前10位的种质资源为GXLF20180011、GXLF2019109、GXLF2019156、GXLF2019118、GXLF2019112、GXLF2019117、GXLF20180006、GXLF2019125、GXLF2019111、GXLF2019136;排名前10位的种质资源全生育期为134~147 d,盛花期茎粗(直径)为2.83~3.66 mm,盛花期株高为41.63~54.73 cm,单株分枝数为2.83~4.19个,每分枝花序数为5.85~6.99个,总花序数为17.55~26.23个/株,结荚花序数为14.33~19.97个/株,鲜草产量为10458.15~48792.75 kg/hm^(2),干草产量为1037.36~5724.34 kg/hm^(2),种子产量为246.75~991.20 kg/hm^(2)。

再生稻栽培模式下冬半年覆盖植被对土壤CH4和N2O排放的影响

为研究冬半年覆盖植被对再生稻(Oryza sativa L.)栽培模式下土壤CH4和N2O排放的影响,采用静态暗箱-气相色谱法观测了再生稻-冬闲(CK)、再生稻-油菜(FR)和再生稻-紫云英(MR)等处理下CH4和N2O的排放通量。结果表明,所有处理的CH4和N2O排放通量在冬半年覆盖植被生长期间较小,在水稻生长季较大。头季稻生长期间土壤CH4累积排放量占全年的85.89%~97.48%,其中MR处理的土壤CH4累积排放量显著低于CK和FR处理;再生季稻生长期间各处理间土壤CH4累积排放量差异不显著,占全年的2.02%~14.11%。头季稻生长期间土壤N2O累积排放量是再生季稻生长期间的1.74~2.43倍,其中头季稻生长期间MR处理土壤N2O累积排放量显著低于CK,再生季稻生长期间各处理差异不显著。各处理CH4和N2O年全球增温潜势(GWP)从大到小依次为FR、CK、MR,且水稻生长季排放的CH4和N2O的GWP远高于冬半年作物期。同时,水稻生长季CH4排放对GWP的贡献远高于N2O,是N2O的1.64~3.87倍。综上,再生稻栽培模式下,头季稻生长期间是控制温室气体CH4和N2O排放的关键时期;再生稻-紫云英模式有利于减少CH4和N2O的排放,是生态环境效益较高的再生稻栽培模式。

“Co-culture Engineering”for Enhanced Phytoremediation of Metal Contaminated Soils

A co-culture of two plant materials, Astragalus sinicus L., a leguminous plant with concomitant nodules, and Elsholtzia splendens Naki-a Cu accumulator, along with treatments of a chelating agent (EDTA), root excretions (citric acid), and a control with E. splendens only were used to compare the mobility of heavy metals in chelating agents with a co-culture and to determine the potential for co-culture phytoremediation in heavy metal contaminated soils. The root uptake for Cu, Zn, and Pb in all treatments was significantly greater (P ＜ 0.05) than that of the control treatment. However with translocation in the shoots, only Cu, Zn, and Pb in plants grown with the EDTA treatment and Zn in plants cocropped with the A. sinicus treatment increased significantly (P ＜ 0.05). In addition, when a co-culture in soils with heavy and moderate contamination was compared, for roots in moderately contaminated soils only Zn concentration was significantly less (P ＜ 0.05) than that of heavily contaminated soils, however, Cu, Zn, and Pb concentrations of shoots were all significantly lower (P ＜ 0.05). Overall, this 'co-culture engineering' could be as effective as or even more effective than chelating agents, thereby preventing plant metal toxicity and metal leaching in soils as was usually observed in chelate-enhanced phytoremediation.

豫南稻区水稻留茬高度对紫云英生长发育及种子产量的影响

为探求豫南稻区紫云英(Astragalus sinicus L.)种植田块最佳水稻留茬高度,设置6种秸秆留茬高度(10、20、30、40、50、60 cm),研究不同留茬高度对紫云英生长发育及种子产量的影响。结果表明,不同留茬高度可以显著影响光照度继而改变地表温度、湿度。高留茬(50~60 cm)可以为紫玉英生长发育前期提供一个适合其生长发育的小气候,而不利于盛花期鲜草产量以及收获期种子产量的获得。30~40 cm留茬高度可以提高紫云英生长发育中后期茎粗、分枝数、单株鲜重,进而提高盛花期鲜草产量和收获期种子产量,在豫南稻区值得在生产中推广应用。