Overexpression of a Foreign Bt Gene in Cotton Affects the Low-Molecular-Weight Components in Root Exudates

Most research in the past using genetically modified crops (GM crops) has focused on the ecological safety of foreign gene (i.e., the gene flow), gene products (for example, Bt (Bacillus thuringiensis) protein), and the safety of transgenic food for humans. In this study, changes in both the species and amounts of low-molecular-weight components in cotton (Gossypium hirsutum L.) root exudates after foreign Bt gene overexpression were investigated under different nutritional conditions. Transgenic cotton containing Bt (Bt-cotton), supplemented with all the mineral nutrients, secreted more organic acids than the wild-type cotton (WT). When nitrogen was removed from the full-nutrient solution, the amount of organic acids secretion of Bt-cotton was lesser than that of WT. The roots of the transgenic cotton secreted lesser amounts of amino acids and soluble sugars than the WT roots in the full-nutrient solution. Deficiencies of P and K caused a large increase in the total amino acid and soluble sugar secretions of both Bt-cotton and WT, with larger increases observed in Bt-cotton. Because transferring the foreign Bt gene into cotton can result in alterations in the components of the root exudates, with the effect varying depending on the nutritional status, the cultivation of genetically modified crops, such as Bt-cotton, in soil environments should be more carefully assessed, and the possible effects as a result of the alterations in the root exudate components should be considered.

Nitrogen application levels based on critical nitrogen absorption regulate processing tomatoes productivity, nitrogen uptake, nitrate distributions, and root growth in Xinjiang, China

The unreasonable nitrogen(N)supply and low productivity are the main factors restricting the sustainable development of processing tomatoes.In addition,the mechanism by which the N application strategy affects root growth and nitrate distributions in processing tomatoes remains unclear.In this study,we applied four N application levels to a field(including 0(N0),200(N200),300(N300),and 400(N400)kg/hm^(2))based on the critical N absorption ratio at each growth stage(planting stage to flowering stage:22%;fruit setting stage:24%;red ripening stage:45%;and maturity stage:9%).The results indicated that N300 treatment significantly improved the aboveground dry matter(DM),yield,N uptake,and nitrogen use efficiency(NUE),while N400 treatment increased nitrate nitrogen(NO_(3)^(-)-N)residue in the 20–60 cm soil layer.Temporal variations of total root dry weight(TRDW)and total root length(TRL)showed a single-peak curve.Overall,N300 treatment improved the secondary root parameter of TRDW,while N400 treatment improved the secondary root parameter of TRL.The grey correlation coefficients indicated that root dry weight density(RDWD)in the surface soil(0–20 cm)had the strongest relationship with yield,whereas root length density(RLD)in the middle soil(20–40 cm)had a strong relationship with yield.The path model indicated that N uptake is a crucial factor affecting aboveground DM,TRDW,and yield.The above results indicate that N application levels based on critical N absorption improve the production of processing tomatoes by regulating N uptake and root distribution.Furthermore,the results of this study provide a theoretical basis for precise N management.

西南桦立木生物量模型的研建

基于2019—2020年在云南省境内采集并测定的157株西南桦立木生物量(其中地上生物量106株、全树生物量51株),建立地上、地下生物量一元(二元)独立模型W=a×D^(b)、W=a×D^(b)×HC,并采用相容性生物量模型建立西南桦地上总生物量与树枝、树叶、树干各分项生物量之和相容的西南桦立木生物量模型,采用根茎比建立地下生物量模型。结果表明:对于西南桦地上生物量,一元、二元模型分别选用权函数W=1/(D^(2))、W=1/(D^(2)H),对于西南桦地下生物量,一元、二元模型分别选用权函数W=1/(D^(0.5))、W=1/(D^(0.5)H^(0.5)),进行加权回归求解模型参数,可明显减小异方差影响及提高模型稳定性;相容性生物量模型解决了立木树枝、树叶、树干等分项生物量之和与地上总生物量不相等问题;从评价指标来看,西南桦地上总生物量和树干生物量模型预估精度均在94%以上;树枝、树叶生物量模型预估精度在92%以上,地下生物量模型预估精度在87%以上。总之,各模型预估精度均达到了国家相关精度要求;研究成果可应用于西南桦生物量的估算。

施氮量对蚕豆养分利用效率的影响

通过盆栽试验,设置3个施氮水平,以不施氮肥为CK,在不同生长时期,测定蚕豆干物质累积、根长,计算养分利用效率。结果表明:与花期和结荚期相比,收获期蚕豆干物质分别增加180%~480%。花期和结荚期,与T_(1)相比,T_(2)和T_(3)施肥量蚕豆根长增加了30.64%、24.19%;21.32%、27.88%,T_(2)和T_(3)之间差异不显著。收获期,与CK相比3个施氮水平下,蚕豆养分阶段累积量分别增加33.01%~74.85%,T_(1)和T_(2)之间差异不显著。与幼苗期相比,3个氮水平下,蚕豆收获期养分吸收效率分别减少48.61%~63.54%。同一生育期内,与CK相比T_(3)氮肥利用效率分别增加4.76%~20.74%,CK与T_(1)、T_(2)之间差异不显著。随施氮量增加,蚕豆氮肥偏生产力、氮肥利用效率增加,蚕豆收获指数相差不明显。总之,施氮量影响蚕豆生长和养分利用,但并不影响收获指数,过量施氮对蚕豆养分吸收利用也无明显促进作用。

Effects of the Dicranopteris linearis root system and initial moisture content on the soil disintegration characteristics of gully erosion

Benggang erosion is caused by a special type of gully erosion in southern China that seriously endangers the local ecology and environment.In this study,typical Benggang collapsing-wall soils were used as the study area to investigate the effects of different initial moisture contents and dicranopteris linearis root weight densities,as well as their interactions on disintegration in orthogonal test method.The results showed that the rate of soil disintegration decreased as a linear function of the initial moisture content.The soil disintegration rate tended to rise and then fall as the root weight density increased,reflecting an optimum root weight density of 0.75-1.00 g/100 cm3.The incorporation of dicranopteris linearis roots was most effective for soil consolidation in the shallow layers of soil.In addition,the disintegration rate of the collapsing-wall soils increases as the soil layer deepened.The dicranopteris linearis root system and initial moisture content had an interactive effect that was more pronounced in deeper soils.However,the combined effect of these processes was always dominated by the initial moisture content.Moderate initial soil moisture content(0.20-0.24 g/g)and the addition of a high root density in dicranopteris linearis(0.75-1.00 g/100 cm3)were the optimal combinations that reduced the disintegration rate.In conclusion,maintaining a suitable natural moisture content in collapsing-wall soils and taking measures that use plants to consolidate soil can effectively prevent and control the occurrence of Benggang erosion.The results of this study provided further insight into the factors that influence soil disintegration and offered a scientific basis for soil erosion management in the southern China.

番茄苗期根际加温对其生长及水分吸收的影响

[目的]本文旨在明确适宜的番茄根际加温温度,为北方早春玻璃温室中番茄苗期根际温度调控提供理论和方法依据,缓解低温环境对番茄生长的危害。[方法]在玻璃温室高架岩棉栽培条件下,采用控温加热带对番茄根际进行加温,并设置3个处理即根际不加温(CK)、根际加温至20℃(T20)、根际加温至25℃(T25),研究不同根际加温条件对早春苗期番茄生长、光合、干物质积累和水分吸收等的影响。[结果]根际加温可显著促进番茄株高、茎粗、叶片数的增加,不同时期处理T20比CK株高提高13.6%~17.0%,茎粗提高10.3%~14.3%,叶片数增加3.4%~12.5%;处理T25比CK株高提高7.2%~9.7%,茎粗提高7.7%~15.6%,叶片数增加0%~15.6%;定植后10 d,番茄净光合速率随根际温度呈先升高后降低的趋势,定植后20 d和定植后30 d,番茄净光合速率随根际温度升高而升高;根际加温促进了番茄对水分的吸收,促进了番茄茎、叶干物质积累,提早开花时间,其中处理T20比CK地上部总干重增加79.3%~85.4%,开花提早5 d,处理T25比CK地上部总干重增加29.2%~72.4%,提早开花时间3 d。[结论]T20处理番茄株高和茎粗最大、积累干物质总量最多、开花时间最早,即20℃是早春苗期番茄较为适宜的根际加温温度。

草甘膦、草铵膦喷施对槟榔根系形态及生理的影响

除草剂防除杂草的同时会对非靶标作物造成一定危害,频繁使用除草剂的海南槟榔园叶片黄化症状更明显,我们推测除草剂可能导致槟榔根系退化,从而引起叶片黄化。为验证这一推断,以幼龄期与成龄期槟榔为试验材料,施用不同浓度草甘膦和草铵膦后,测定分析槟榔根系生长发育形态指标、根系活力、气生根组织结构、不同类型根系占比等。结果表明,幼龄期槟榔根系以直径0~1.5 mm根系为主,数量占总根的88%以上,表面积占总根的63%以上。与人工除草、对照(不除草)相比,喷施草甘膦和草铵膦显著降低槟榔幼苗根系鲜干质量、白色吸收根比例、吸收根活力。对于成龄期槟榔气生根,喷施草甘膦和草铵膦均引起气生根药剂残留,且农残量随施用浓度增加而增加,并阻碍槟榔气生根发育;草甘膦处理后14 d气生根死亡数达到最大,草铵膦处理后28 d达到最大。草铵膦损害气生根组织结构,使新根内皮层排列稀疏,表皮组织厚度增加,木栓化程度加深,导致根表皮细胞大量死亡,抑制气生根伸长与增粗。说明喷施草甘膦和草铵膦会导致槟榔根系木栓化,加速根系死亡,从而抑制其根系生长与发育,引起槟榔园叶片黄化。

着力提升制造业产业链供应链韧性与安全水平研究——以XZ市工程机械制造业为例

厘清供应链韧性和安全水平的影响因素是预防产业链供应链“断链”的基础,也是应对百年未有之大变局、实现制造业“双链”深度融合的重要抓手[1]。在对XZ市工程机械领域进行深度调研和阅读大量文献的基础上,文章运用扎根理论理出了工程机械供应链韧性六个维度的指标,结合企业近几年的经营数据和专家意见,运用熵权法-Topsis赋予了供应链韧性指标权重,并对其进行了评测,为科学构建XZ市工程机械制造业供应链韧性指标体系和提升其安全水平提供了实践启示。

北斗三号B1I/B2a相对定位精度分析

为了研究北斗三号导航卫星系统(BDS-3)B1I/B2a相对定位精度,通过GAMIT10.71软件处理澳大利亚地区10个MGEX跟踪站数据。实验结果表明:格洛纳斯(GLONASS)G1/G2的N、E、L基线向量标准差最大分别达到8.00 mm,12.10 mm和10.60 mm;北斗二号导航卫星系统(BDS-2)B1I/B2I的U基线向量标准差最大达到28.70 mm。基线长度与基线长度标准差(STD)呈正相关。BDS-3 B1I/B2a、伽利略导航卫星系统(Galileo)E1/E5a和全球定位系统(GPS)L1/L2的点位中误差和加权均方根(WRMS)整体较小,精度较高;BDS-2 B1I/B2I和GLONASS G1/G2则整体较大,精度较低。实验结果进一步表明:BDS-3 B1I/B2a相比较于BDS-2 B1I/B2I的定位精度有大幅度提升。

含未知输入非线性系统的扩展平方根容积卡尔曼滤波算法

针对工程实际应用中存在的未知输入会导致经典的非线性滤波器状态估计精度下降甚至滤波发散的问题,提出了一种基于最小方差无偏估计(minimum variance unbiased estimation,MVUE)准则的扩展平方根容积卡尔曼滤波(extended square-root cubature Kalman filter,ESRCKF)算法。首先,结合上一时刻未知输入估计值对状态一步预测值进行修正,得到含未知输入条件下的状态预测值。其次,设计新息并采用加权最小二乘(weighted least squares,WLS)法获取当前时刻未知输入的无偏估计。最后,通过最小化协方差矩阵的迹,同时采用拉格朗日乘子法和舒尔补引理得到系统状态的最小方差无偏估计。仿真结果表明,相比于现有的非线性滤波算法,ESRCKF算法提高了在处理含未知输入非线性系统时的状态估计精度,并能同时实现系统状态和未知输入的最优估计,验证了该算法的有效性。

Root Physiological and Morphological Characteristics of Two Rice Cultivars with Different Nitrogen-Use Efficiency

The variation in nitrogen (N) uptake by rice has been widely studied but differences in rice root morphology that may contribute to this variation are not completely understood. Field and greenhouse experiments were carried out to study N accumulation, root dry weights, total root lengths, root surface areas, and root bleeding rates of two rice cultivars, Elio with low N-use efficiency and Nanguang with high N-use efficiency. Low (1 mmol N L-1) and high (5 mmol N L-1) N applications were established in the greenhouse experiment, and the N rates were 0, 120, and 240 kg ha-1 in the field experiments at Jiangning and Jiangpu farms, Nanjing, China. The results showed that the N accumulation, root dry weight, total root length, and root surface area increased with an increase in N application. At the heading stage, N accumulation in the shoots and roots of Nanguang was greater than that of Elio in the field experiments and that of Elio at 5 mmol N L-1 in the greenhouse experiment. After the heading stage, N accumulation was higher for Nanguang at both 1 and 5 mmol N L-1 in the greenhouse experiment. The total root length and root surface area were significantly different between the two cultivars. Over the range of the fertilizer application rates, the root lengths of Nanguang at Jiangning Farm were 49%-61% greater at booting and 26%-39% greater at heading than those of Elio, and at Jiangpu Farm they were 22%-42% and 26%-38% greater, respectively. Nanguang had a greater root bleeding rate than Elio. It was concluded that the N-use efficiency of the two rice cultivars studied depended to a great extent on the root morphological parameters and root physiological characteristics at different growth stages.

在线社交网络中基于多态信任融合的信任估计

为提高大型在线社交网络中信任计算方法的准确性和鲁棒性,采用共被引和转置信任传播操作,提出一种基于多态信任融合的信任估计方法估计连续信任/不信任值。结合信任者、被信任者的相邻用户的信息以及被信任者对信任者的信任,平均估计出两个用户信任或被其它用户信任的差异,以及一个用户信任另一个用户和被该用户信任的差异;利用这些差异,计算4种部分信任估计值,将这些部分估计值加权平均,得到信任者对被信任者的最终信任估计值。仿真结果表明,所提方法比其它最新的现有信任计算算法更准确和鲁棒,对应用于大型网络更高效。

Numerical Simulation of Root Growth Dynamics of CO_2-Enriched Hybrid Rice Cultivar Shanyou 63 Under Fully Open-Air Field Conditions

Hybrid indica rice （Oryza sativa L.） cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle, and high yield potential. However, no attention has been given to its root growth dynamic responses to rising atmospheric CO2 concentration （[CO2]） in conjunction with nitrogen （N） availability. Free air COz enrichment （FACE） and N have significant effects on rice root growth. In this experiment, a hybrid cultivar Shanyou 63 （Oryza sativa L.） was used to study the effects of FACE and N levels on roots growth of rice. The results showed a significant increase in both adventitious root volume （ARV） and adventitious root dry weight （ARD） under the FACE treatment. The application of nitrogen also increased ARV and ARD, but the increase was smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root volume and dry weight were built with the time as the driving factor. The models illustrated the dynamic development of rice adventitious root volume and dry weight after transplanting, regulated either by the influence factor of atmospheric [CO2] or by N application. The models were successfully used to predict ARV and ARD under FACE treatment in a different year with the predicted data being closely related to the actual experimental data. The model had guiding significance to growth regulation of rice root under the condition of atmospheric [CO2] rising in the future.

Distribution and Quantity of Root Systems of Field-Grown Erianthus and Napier Grass

Cellulosic bioethanol produced from non-edible plants reduces potential food-fuel competition and, as such, is receiving increasing attention. In the raw material production of cellulosic bioethanol, the aboveground biomass of plants is entirely harvested;consequently, the plant roots represent the major source of organic matter incorporated into the soil. We selected Erianthus and Napier grass as the raw materials for cultivation in Asia. However, information about whether these 2 species provide sufficient root volume to sustain soil fertility is limited. Therefore, we examined the spatial distribution of the roots of these 2 plants, and quantified root mass and length. Erianthus and Napier grass were either grown in fields or greenhouses in Tokyo (Japan) and Lampung (Indonesia), and then their roots were exposed from adjacent soil profiles. Both species developed large, deep roots, penetrating 2.0-2.6 m deep into the soil. Root depth indexes showed that the roots of both species penetrated much deeper into the soil compared to monocot crop species, being more comparable to dicot species. Erianthus developed a root mass and length of 384-850 g·m-2 and 28.8-35.8 km·m-2, while the values for Napier grass were 183-448 g·m-2 and 15.6-43.6 km·m-2, respectively. These values exceeded the maximum values previously recorded for common crop species. Our study confirmed that Erianthus and Napier grass develop deep root systems, with substantially large biomass;hence, we suggest that both plants supply root biomass in large quantities, representing possible major sources of soil organic matter.

Effects of maize root exudates and organic acids on the desorption of phenanthrene from soils

The effects of maize root exudates and low-molecular-weight-organic anions （LMWOAs） on the desorption of phenanthrene from eight artificially contaminated soils were evaluated. A significant negative correlation was observed between the amounts of phenanthrene desorbed and the soil organic carbon （SOC） contents （P 〈 0.01）, and the influences of soil pH and clay content on phenanthrene desorption were insignificant （P 〉 0.1）. Neither maize root exudates nor oxalate and citrate anions influenced desorption of phenanthrene with the addition of NaN3. A faster phenanthrene desorption occurred without the addition of NaN3 in the presence of maize root exudates than oxalate or citrate due to the enhanced degradation by root exudates. Without the addition of NAN3, oxalate or citrate at different concentrations could inhibit phenanthrene desorption to different extents and the inhibiting effect by citrate was more significant than by oxalate. This study leads to the conclusion that maize root exudates can not enhance the desorption under abiotic condition with the addition of NaN3 and can promote the desorption of phenanthrene in soils without the addition of NaN3.

Determination of Organic Acids in Root Exudates byHigh Performance Liquid Chromatography: III. Effectsof Interfering Factors

INTRODUCTIONCollectionofrootexudateswasakeysteptodeterminethecomponentsandamountsofrootexudates.Asfordifferelltmediaofplaotgrowth,themethodsforcollectingrootexudateswerealsodifferent.Undersolutionculture,rootexudateswerefrequentlyobtainedbysubmerging...

Root Characters of Maize as Influenced by Drip Fertigation Levels

The efficient use of water by modern irrigation systems is becoming increasingly important in arid and semi-arid regions with limited water resources. Field experiments were conducted during 2008-2010 to study the effect of drip fertigation with water soluble fertilizer on root growth of maize under maize based intercropping system. The experiment was laid out in strip plot design with three replications. The treatment consists of nine fertigation levels in main plots and four inter crops in sub plots. Root spread and root dry mass were increased under drip fertigation practices while rooting depth was more under surface irrigation. Drip fertigation with water soluble fertilizer improved the root system by inducing new secondary roots which are succulent and actively involved in physiological responses. Drip fertigation has pronounced effect on the root architecture especially in the production of highly fibrous root system.

早播对新疆阿魏一年生种苗质量的影响

[目的]以新疆阿魏(Ferula sinkiangensis K.M.Shen)种子为试验材料,研究早播对新疆阿魏一年生种苗质量的影响。[方法]将种子层积处理后,分早播和常规播种2种处理,待种苗进入休眠后将根挖出,以根的重量、长度、宽度为指标评价种苗质量。[结果]早播较常规播种根重、根长、根粗分别增加251.57%、60.06%、40.52%,以根重为参考,早播种苗中有17.65%达到一级、10.29%达到二级、22.06%达到三级,而常规播种中没有能达到一级和二级的,仅有2.25%达到三级,其余未入级。[结论]适时早播能够有效提高新疆阿魏一年生种苗的质量。

基于根冠协调发展的东北春玉米高产种植密度分析

植株地上部与地下部的协调是生长发育的内在需求,分析种植密度对冠根协调的影响能够为玉米增密高产理论和技术提供新的视角。本研究于2020-2021年在吉林省中国农业科学院作物科学研究所公主岭试验站进行,以郑单958和先玉335两个耐密品种为试验材料,调查了玉米关键生育时期内根系和冠层的相关指标在产量稳定区间的2个种植密度(D1:6.75万株hm^(-2);D2:9.75万株hm^(-2))下的差异。试验条件下,种植密度从D1增加到D2,玉米的单株干物质积累量、根干重等均出现显著降低,群体指标表现不同。其中,2个品种的群体籽粒产量未出现显著提升,在根系各指标达到最大值的吐丝后15 d(R2期),群体根干重、根长密度等也未出现显著提升。随着生育进程推进,玉米的冠根比呈指数函数增长(y=ae^(bx)),增加种植密度显著提高了玉米冠根比,粒根比、叶根比也增加,根系压力增大。研究结果表明,玉米根系对种植密度的响应程度与地上部存在差异,在产量水平基本相当的前提下,根系压力较小的种植密度更有利于冠根协调和合理群体的构建。