Model Construction and Visualization Simulation of Soybean Root System

This paper mainly focused on the growth law, model construction and visualization of a soybean root. A pot experiment was conducted in the laboratory to collect root system data and measure soybean root＇s length, diameter and number by excavating in different periods. On the basis of an in-depth analysis of root structure geometry, we analyzed the collected experimental data with logistic equations, and got the growth of soybean root equation, according to its morphological structure characteristics of self-similarity, and discussed the virtual modeling method on the soybean root based on L-system and in Visual c＋＋ Using OpenGL technology to achieve a soybean root system topology model and visualization simulation.

A LAMP-assay-based specific microbiota analysis reveals community dynamics and potential interactions of 13 major soybean root pathogens

Soybean root diseases are associated with numerous fungal and oomycete pathogens;however,the community dynamics and interactions of these pathogens are largely unknown.We performed 13 loop-mediated isothermal amplification(LAMP)assays that targeted specific soybean root pathogens,and traditional isolation assays.A total of 159 samples were collected from three locations in the Huang-Huai-Hai region of China at three soybean growth stages(30,60,and 90 days after planting)in 2016.In LAMP results,we found that pathogen communities differed slightly among locations,but changed dramatically between soybean growth stages.Phytophthora sojae,Rhizoctonia solani,and Fusarium oxysporum were most frequently detected at the early stage,whereas Phomopsis longicolla,Fusarium equiseti,and Fusarium virguliforme were most common in the later stages.Most samples(86%)contained two to six pathogen species.Interestingly,the less detectable species tended to exist in the samples containing more detected species,and some pathogens preferentially co-occurred in diseased tissue,including P.sojae–R.solani–F.oxysporum and F.virguliforme–Calonectria ilicicola,implying potential interactions during infection.The LAMP detection results were confirmed by traditional isolation methods.The isolated strains exhibited different virulence to soybean,further implying a beneficial interaction among some pathogens.

Overexpression of GmBIN2,a soybean glycogen synthase kinase 3 gene,enhances tolerance to salt and drought in transgenic Arabidopsis and soybean hairy roots

Glycogen synthase kinase 3 （GSK3） is a kind of sedne/threonine kinase widely found in eukaryotes. Many plant GSK3 kinases play important roles in regulating stress responses. This study investigated BRASSINOSTEROID-INSENSITIVE 2 （GmBIN2） gene, a member of the GSK3 protein kinase family in soybean and an orthologue of Arabidopsis BIN2/AtSK21. GmBIN2 expression was increased by salt and drought stresses, but was not significantly affected by the ABA treatment. To examine the function of GrnBIN2, transgenic Arabidopsis and transgenic soybean hairy roots were generated. Overexpression of GmBIN2 in Arabidopsis resulted in increased germination rate and root length compared with wild-type plants under salt and mannitol treatments. Overexpression of GmBIN2 increased cellular Ca2~ content and reduced Na~ content, enhancing salt tolerance in transgenic Arabidopsis plants. In the soybean hairy root assay, overexpression of GmBIN2 in transgenic roots also showed significantly higher relative root growth rate than the control when subjected to salt and mannitol treatments. Measurement of physiological indicators, including proline content, superoxide dismutase （SOD） activity, and relative electrical conductivity, supported this conclusion. Furthermore, we also found that GmBIN2 could up-regulate the expression of some stress-related genes in transgenic Arabidopsis and soybean hairy roots. Overall, these results indicated that GmBIN2 improved tolerance to salt and drought in transgenic Arabidopsis and soybean hairy roots.

Impact of long-term chemical fertilizer and organic amendment to Fusarium root rot of soybean

Soil suppressiveness to Fusarium root rot of soybean had been observed in a black soil field after a long-term fertilization with nitrogen(N)and phosphorus(P)fertilizer combined with pig manure as organic amendment(NPM),rather than that with only nitrogen and phosphorus fertilizer(NP)or no fertilizer(NF).To determine the microbial role on this suppressiveness,fungal and bacterial community characteristics in NPM,NP and NF treatments were investigated by q PCR and DGGE.Compared with the similar bacterial community characteristics among 3 treatments,fungal community,especially Fusarium population size and community composition in NPM treatment were different with those of NP and NF groups.Based on the isolation and pathogenicity test,pathogenic F.oxysporum,F.graminearum,F.verticillioide and F.lateritium absolutely dominated Fusarium community in NF and NP groups.Nonpathogenic F.avenaceum,F.equiseti,F.culmorum,F.redolens,F.solani and F.tricinctum dominated Fusarium community in NPM group.Isolation rate of pathogenic Fusarium in NPM reduced from 100%to 38%in NF.These results suggested that the dominance of soil non-pathogenic Fusarium population induced by organic amendment might play an important role on suppressing Fusarium root rot in the tested field.

Evolution of Root Characters of Soybean Varieties Developed in Different Years

It was studied that the evolution of root characteristics among 42 soybean varieties developed in Heilongjiang and Jilin Province in different years. The results showed that there were differences on the root characteristics among soybean varieties. From 1950s to 1990s, root fresh weight, root volume, root surface, root dry weight, lateral root length of main root characters tendedly increased with the variable development

镁营养对大豆苗期生长及根系形态构型的影响

【目的】镁是植物生长必需的矿质营养元素,研究大豆在不同镁浓度下的苗期生长情况及根系三维构型的动态变化。【方法】以磷高效大豆品种‘粤春03-3’为研究对象,营养液培养,设置镁浓度为0、262.5、525.0、787.5和1050.0μmol/L,分析苗期大豆的生长发育状况。在此基础上,利用根系三维定量系统对正常镁处理(525.0μmol/L,对照)及缺镁处理(0μmol/L)的大豆根系三维构型进行动态定量化分析。【结果】与525.0μmol/L对照相比,0μmol/L缺镁处理大豆的地上部干质量、根冠比、老叶SPAD、总根长和根系总表面积分别减少89.04%、48.67%、51.42%、93.36%和94.31%。而其他3个镁浓度条件下,大豆生长与对照差异较小。根系三维构型研究发现,与对照相比,随着处理时间的延长,缺镁处理显著降低大豆根系的总根长、总根表面积、根重心、根尖数、凸包体积、最大根宽、最小根宽、最大根深、最大根宽/最大根深,对根系充实度、分根繁茂度和根体积分布的影响较小。【结论】本研究明确了大豆对外界镁有效性的适应范围较广,借助优化的根系三维重建技术,阐明缺镁显著降低大豆根系的总根长、根尖数、根重心、最大根宽等,但对根系充实度、分根繁茂度、根体积分布动态变化规律的影响较小。研究结果对大豆镁肥的合理施用和镁营养诊断有一定的指导意义。

苗期水分亏缺对大豆根系生长及产量的影响

为了分析大豆苗期不同程度水分亏缺对生长指标以及生理特性影响,本文以河南省濮阳县大豆作物为主要研究对象,采用盆栽试验方法,分析水分亏缺对根系干物质积累量、生理指标、和产量影响。结果表明:T_(1)处理大豆根长、根直径、根体积、根系活力值均最大,分别为75.11 cm、12.43 mm、37.56 cm^(3)、168.33 mg/g·h;T_(1)处理开花期、结荚期、鼓粒期的大豆根系干物质积累量均最大,分别为3.17 g/株、5.46 g/株、6.05 g/株;T_(2)、T_(3)处理开花期、结荚期、鼓粒期的大豆根系干物质积累量均低于对照;大豆根系过氧化物酶活性、丙二醛含量、可溶性糖含量、脯氨酸含量呈上升趋势,而大豆根系可溶性蛋白含量呈先增加后下降趋势。T_(1)处理蛋白含量最高,为18.55 mg/g,显著高于其它处理;T_(1)处理大豆节数、单株粒数、单株荚数、单株产量均最大,所以,大豆苗期适度亏水有利于促进大豆生长。

Conidia of one Fusarium solani isolate from a soybean-production field enable to be virulent to soybean and make soybean seedlings wilted

Fusarium is usually thought to cause soybean root rot, which results in a large quantity of annual yield loss in soybean production, by its secretions including Fusarium toxins and cell wall degrading enzymes, but not by the conidia themselves that do not underlie any virulence so far. Here we report that the conidia of one Fusarium solani isolate are able to be virulent to soybean and make soybean seedlings wilted alone. We isolated them from the wilted plants in a soybean-production field and molecularly identified 17 Fusarium isolates through phylogenetic analysis. Of them, except for one isolate that showed diversity of virulence to different soybeans （virulent to one soybean whereas avirulent to another soybean）, the others were all virulent to the two tested soybeans： both conidia cultures and secretions could make soybean seedlings wilted at 5 days post infection, and their virulence had dosage effects that only conidia cultures of at least 5×10^6 conidia mL-1 could show virulence to soybean; however, the sole conidia of the F. solani isolate #4 also exhibited virulence to soybean and could make soybean seedlings wilted. Finally, we developed the specific cleaved amplified polymorphic sequences （CAPS） markers to easily differentiate Fusarium isolates. The isolate #4 in this work will likely be used to investigate the new mechanism of virulence of Fusarium to soybean.

Resistance identification of bivalent fungi-resistant genes transformed soybean to Phytophthora sojae

Soybean is one of the most important sources of edible oil and proteins in the world. However, it suffers from many kinds of fungal diseases which is a major limiting factor in soybean production. The fungal disease can be effectively controlled by breeding plant cultivars with genetic transformation. In this study, the resistance to Phytophthora sojae of five bivalent transgenic soybean lines was identified using the hypocotyls inoculation technique. The lines were the T2 of the transgenic soybean which were transformed with kidney bean chitinase gene and barley ribosome inactivating protein gene, and were positive by Southern Blot analysis. The resistance difference was studied through comparing the death percentage of transgenic soybean with the control. The results showed that four lines were more resistant to P sojae, whereas other one had no significant difference in comparison with the control. These transgenic soybean lines with enhanced resistance to P sojae will be useful in soybean resistance breeding.

不同Cas9启动子对大豆CRISPR/Cas9系统效率的作用分析

CRISPR/Cas9系统作为高效基因编辑系统,已被广泛应用于动植物中。多种Cas9基因启动子,如RPS5A、YAO等被报道用于提高CRISPR/Cas9系统的基因编辑效率。但在大豆中,不同Cas9启动子对CRISPR/Cas9基因编辑系统效率的影响还没有被阐明。本研究选择了6个已知功能的高效Cas9启动子(p35S、pGmRPS5Ab、pGmRPS5Ac、pAtRPS5A、pGmYAO、pZmUbiquitin)和1个大豆内源未知功能的启动子(pGmHE),构建CRISPR/Cas9基因敲除载体。通过农杆菌介导的大豆发根系统,检测这些Cas9启动子对大豆内源基因GmSPA1a和GmEID1的编辑效率,结果显示大豆内源启动子pGmRPS5Ab对靶基因的编辑效率最高,pAtRPS5A、p35S、pZmUbiquitin对下游基因的编辑效率高于pGmYAO和pGmRPS5Ac。进一步对靶位点测序峰图的分析发现,使用了pGmRPS5Ab和pAtRPS5A启动子的测序峰图中,高峰占比较大,分别为64.0%和58.6%;而使用p35S的测序峰图中,低峰占比较高,为63.3%。这表明pGmRP5SAb和pAtRPS5A启动子不但编辑效率高,而且编辑效果好,更有利于在下一代中分离出纯合突变体植株。这些结果将为构建高效大豆基因编辑载体提供参考,为提高大豆基因编辑效率提供依据。

基于生长函数的大豆根系生长的三维可视化模拟

植物的可视化模拟与仿真能为植物生长研究提供直观、迅捷的科学研究方法。植物根系在生长介质中的三维空间造型与分布,对水分养分的利用具有十分重要的作用。为了避免植物根系生长环境的不可见性和次要因素的影响,定量地直观地研究根构型的适应性变化,将植物根构型的多个生长函数和植物根系的形态发生模型耦合起来,结合可视化方法,建立了植物根系生长的三维可视化模拟系统。以大豆根系为研究对象,根构型的生长函数采用前期研究已获得的三次多项式形式;形态发生模型采用微分L系统理论编译其生成规则;可视化方法采用一系列连接在一起并平滑处理的圆台代表根轴。系统设计成只需输入三次多项式形式的生长函数的系数,就可直观地、连续地、可控地获得该根系生长的可视化图形和根构型几何参数。

大豆根系的研究

根系在作物的生长发育过程中起着重要的作用。有关大豆根系的研究不如地上部深入 ,大豆根系研究信息的缺乏在一定程度上影响了育种工作的成效。文章概括介绍了与大豆育种和生产有关的大豆根系方面的研究 。

氮肥施用对高产大豆根系、干物质积累及产量的影响

在本试验生产条件下和施氮量范围内,具有4500kg·hm-2以上产量潜力品种黑农41随着始花期施氮量的增加,氮肥对大豆根瘤形成的抑制作用加大,推迟单株伤流液出现的高峰期,增加全生育期的叶面积指数和干物质积累,增加各产量构成因素和产量。始花期一次施纯氮90kg·hm-2春大豆籽粒产量可达5012.55kg·hm-2。

间作玉米大豆根系分泌物中有机酸的变化特征

通过水培试验,收集了不同生育期单作玉米、单作大豆、玉米大豆分隔间作(根系用尼龙网分隔)及玉米大豆间作(根系不分隔)下的根系分泌物,并通过高效液相色谱方法分析不同种植模式下不同生育期的玉米大豆根系分泌物中有机酸的变化特征。结果表明:与单作相比,在有机酸分泌种类上,分隔间作玉米苗期增加苹果酸,减少顺丁烯二酸;喇叭口期无变化;孕穗期减少苹果酸。间作玉米苗期增加苹果酸,喇叭口期减少酒石酸和苹果酸,孕穗期减少乳酸和顺丁烯二酸;分隔间作大豆苗期增加柠檬酸,花期减少酒石酸和乳酸、增加乙酸,鼓粒期增加酒石酸和苹果酸;间作大豆苗期增加柠檬酸,花期减少酒石酸和苹果酸、增加乙酸,鼓粒期增加酒石酸和苹果酸、减少乳酸和顺丁烯二酸。在分泌速率上,分隔间作玉米喇叭口期增加了284.80%,间作玉米在喇叭口期和孕穗期分别增加了159.24%、88.01%;间作大豆在鼓粒期增加了149.59%,分隔间作大豆在苗期、花期和鼓粒期分别增加了114.65%、24.24%、389.38%。间作和分隔间作改变了有机酸分泌种类,间作能更长时期提高玉米有机酸分泌速率,分隔间作能更长时期提高大豆根系的有机酸分泌速率。

犁底层及作物根系影响下壤中流形成机理研究

为了研究犁底层及作物根系影响下壤中流的形成机理,以我国东北黑土区大豆坡耕地为研究对象,试验设计测定有、无犁底层及大豆根系条件下土壤物理特性、土壤水分湿润峰迁移和鼓粒期大豆根系形态。结果表明,研究区降雨强度小于16.8 mm/h时,犁底层以上土壤含水量超过49.8 mm产生壤中流;降雨强度大于16.8 mm/h时,假定在犁底层位置处土壤含水量超过田间持水量,湿润峰到达犁底层处且含水量等于田间持水量时土壤水分剖面形状相同,产生壤中流。基于以上假定构建壤中流产流时刻模拟模型,利用模型对裸土及大豆根系影响下壤中流产流时间进行模拟,相对误差为6.6%和0.4%,说明该模型适用于犁底层及大豆根系影响下壤中流产流时间的预测,同时也说明以上假定的合理性。

大豆成苗期抗旱性与根系生长的关系

选择抗旱性强、中、弱的大豆品种各5个,在试验室条件下研究成苗期抗旱性与根系生长、胚轴伸长的关系。结果表明:抗旱性强的品种发根早,主根长,侧根数量多,侧根总长度长,胚轴长,成苗率高。在干旱条件下的趋势更为明显。

基于15N示踪法的双根大豆系统氮素吸收和分配特性研究

【目的】施氮可以促进大豆生长并提高产量,同时会抑制根瘤生长和固氮。因此研究大豆对不同形态氮素的吸收、分配及再分配特点,可以为解析大豆氮的转运特性及施氮对根瘤的系统性抑制提供参考。【方法】利用嫁接方法,制备具有两个根部和一个地上部的双根大豆植株,在砂培条件下分别以NO3^-和NH4^+为氮源设置两种试验处理。试验Ⅰ,一侧施50 mg/L的^15NO3^-或^15NH4^+(A侧),另一侧不施氮(B侧);试验Ⅱ,一侧施50 mg/L的^15NO3^-或^15NH4^+(A侧),另一侧施同形态的50 mg/L的NO3^-或NH4^+(B侧)。于始花期(R1)和始粒期(R5)取样两次,将植株分为A根、B根、A侧根瘤、B侧根瘤、茎、叶片、叶柄、荚等部位,用于测定^15N丰度、干重和氮含量等指标。【结果】试验Ⅰ和试验Ⅱ结果发现,大豆A和B两侧根瘤的^15N丰度均高于自然丰度(0.365%),说明根瘤的生长发育过程中,所需要的氮不是全部来自自身固氮,还需要从根中吸取氮。与试验Ⅰ相比,试验Ⅱ的根瘤固氮率明显下降,表明大豆植株优先吸收利用肥料氮。NO3^-与NH4^+处理相比,各器官^15N丰度均没有显著性差异,说明在50 mg/L的氮浓度下,NO3^-和NH4^+对大豆的氮营养没有显著差异。试验Ⅰ和试验Ⅱ均发现大豆B侧根及根瘤的^15N丰度高于自然丰度(0.365%),且小于施加的肥料氮的^15N丰度(3.63%),表明A侧根吸收的氮会经地上部转移到B侧的根及根瘤中,即根吸收的肥料氮会以一定的比例运输到地上部,随后会再次重新分配回根及根瘤中。本试验将双根大豆系统中地上部和B侧根及根瘤看成一个氮转移系统,利用^15N丰度的差异,构建了R1~R5期地上部向根及根瘤转移氮量的计算方法。经计算发现,当施氮浓度为50 mg/L时,在始花期至始粒期,根来自地上部转移的氮占根部氮积累量的28.4%~40.8%,根瘤来自地上部转移的氮占其氮积累量的14.4%~17.2%。【结论】根瘤生长所需要的氮不是全部来源于自身固氮,有一部分来源于根系吸收的氮。在有肥料氮存在时,大豆植株优先吸收肥料氮。根系吸收的肥料氮以及根瘤固氮被运输到地上部后,会再次重新分配回根及根瘤中。在50 mg/L的氮浓度下,氮素形态(NO3^-和NH4^+)不会影响大豆植株对氮的吸收及分配。

大豆抗旱种质的鉴定及其与根系的关系

从辽宁省主要推广品种中选出20份优异种质资源,依据株高、叶面积指数、茎、叶生物量为指标,采用平均隶属函数值方法鉴定了大豆苗期耐旱性。结果从供试材料中共筛选出大豆生长前期较强耐旱型(2级)品种2个,干旱较敏感型(4级)品种3个,中间型(3级)品种15个。大豆的平均耐旱隶属函数值与干旱胁迫下的相对根表面积、相对根生物量分别呈显著、极显著正相关。大豆的耐旱平均隶属函数值与根性状比未达显著相关程度。胁迫条件下大豆的根直径与根表面积、根体积,根表面积与根体积呈显著正相关,非胁迫条件下大豆的根直径与根体积、根生物量,根体积与根表面积、根生物量呈显著正相关。干旱胁迫及非胁迫条件下大豆的茎、叶生物量均呈显著正相关。

大豆和蚕豆苗期根系生长特征的比较

大豆和蚕豆是西北地区间套作生产中广泛种植的豆科作物,但二者在与禾本科作物间作时差异十分明显,蚕豆相对于大豆具有更强的竞争能力.从大豆和蚕豆的根系入手,研究了大豆和蚕豆在苗期根系生长发育和形态的差异.采用PVC管砂培装置,通过扫描仪扫描根系,用图像分析软件WinRHIZO进行了研究.结果表明,出苗42 d时,蚕豆根表面积是大豆根表面积的2.61倍;出苗14 d时,大豆根系在整个砂层中均有分布,而蚕豆根系只分布在表层;大豆根较细,大部分根的直径为0.25～1.0 mm,相对于大豆而言,蚕豆根较粗,大部分根直径为0.5～1.5 mm.蚕豆根较粗,所以有更大的表面积,而且它的根系分布在上层的比例大于大豆,这些因素决定了它的吸收能力强于大豆,能更好地利用上层土壤养分.这是蚕豆竞争能力强于大豆的原因之一.

大豆生长及叶绿素荧光特性对铝胁迫的反应

采用溶液培养方法,设置了不同的铝处理浓度和处理时间,对铝毒胁迫下的两个大豆品种(浙春2号、浙春3号)的根系生长和叶片的叶绿素荧光进行了研究。结果表明:铝抑制了大豆的根系干重、根系总长度、根系体积的增加。在高浓度铝处理下,根系生长7 d后就受到了明显抑制。对茎叶干重的影响在铝处理14 d后才得到表现,茎叶部出现铝毒症状滞后于根部。根尖的根系活力在10 mg/L的铝浓度下有所增加,增强了根系吸收水分和矿质元素的能力。根系质膜透性随着铝处理浓度的增加而增大,在90 mg/L的铝处理下达到最大,植株受到严重伤害。低铝(10 mg/L)使大豆叶片的叶绿素含量少量增加,高铝(90 mg/L)胁迫叶绿素含量降低,且叶绿素a下降的幅度大于叶绿素b。荧光参数的研究表明,随着铝胁迫的增加,Fo增大,Fm、Fv/Fm下降,植株抵抗逆境的能力下降,光合电子传递减小,最终导致光合速率下降。两个大豆品种具有基因型差异,浙春2号比浙春3号更耐铝胁迫。