Characterization of root architecture in an applied core collection for phosphorus efficiency of soybean germplasm

In the present study, we constructed an “applied core collection“ for phosphorus (P) efficiency of soybean germplasm using a GIS-assisted approach. Systematic characterization and comparative analysis of root architecture were conducted to evaluate the relationship between root architecture and P efficiency and its possible evolutionary pattern. Our results found that: i) root architecture was closely related to P efficiency in soybean. Shallow root architecture had better spatial configuration in the P-rich cultivated soil layer hence higher P efficiency and soybean yield; ii) there was a possible co-evolutionary pattern among shoot type, root architecture and P efficiency. The bush cultivated soybean had a shallow root architecture and high P efficiency, the climbing wild soybean had a deep root architecture and low P efficiency, while the root architecture and P efficiency of semi-wild soybean were intermediate between cultivated and wild soybean; iii) P availability regulated root architecture. Soybean roots became shallower with P addition to the topsoil, indicating that the co-evolutionary relationship between root architecture and P efficiency might be attributed to the long-term effects of topsoil fertilization. Our results could provide important theoretical basis for improving soybean root traits and P efficiency.     

Quantitative analysis of 3-dimensional root architecture based on image reconstruction and its application to research on phosphorus uptake in soybean

The root system is an important organ for plants not only because it absorbs water and nutrients, but also because it provides anchorage against uprooting forces[1,2]. Root architecture is the spatial configuration of the root system in the growth medium[…     

低磷胁迫下杉木无性系根系形态及养分利用响应研究

【目的】研究不同杉木无性系苗木在低磷胁迫下的根系形态和养分利用特征,为提高杉木养分利用效率的遗传改良提供参考。【方法】以5个杉木无性系组培苗为材料,采用土壤盆栽实验,设置缺磷(PO, KH₂PO₄ 0 mmol/L)和正常供磷(PN, KH₂PO₄ 1.0 mmol/L)两种改良Hoagland营养液进行浇灌处理,培养60 d后测定其生物量(根、茎、叶)、根系形态参数及其养分(磷、氮、钾、钙、镁)累积量和利用效率。【结果】①随施磷水平的变化,杉木无性系的干物质质量和根系形态指标显示出极显著的基因型效应差异。②缺磷处理使杉木无性系的根、茎、叶和整株干物质质量分别减少20.06%、20.68%、14.07%和16.78%,根冠比则增加,总根长、总根表面积、总根体积分别增加17.31%、17.69%、24.77%,根平均直径减少8.22%,细根比例显著提高。③缺磷使杉木无性系整株磷累积量减少17.91%,而磷利用效率呈上升趋势,同时磷在根系中的含量降低16.35%,但茎、叶中的含量在处理间差异不显著; 缺磷还使整株对钾的累积量减少27.58%,钙和氮分别减少18.56%和14.95%,镁减少12.85%。④经主成分分析发现,杉木无性系植株的粗根长、细根长、根冠比、根干物质质量与低磷胁迫响应密切; 回归分析显示,细根量对植株的磷吸收量有显著正向效应。【结论】杉木无性系根系形态指标随施磷水平变化呈极显著的基因型效应差异,缺磷胁迫使苗木地上部干物质质量减少,根平均直径减少,细根比例增大,根冠比增大,根系趋向于磷高效吸收的根构型转变,进而提高对低磷胁迫的遗传适应性。     

Secretive expression of Aspergillus fumigatus phytase in tobacco improves phosphorus nutrition in plant

To generate transgenic plants capable of utilizing exogenous phytate,an Aspersgillus fumigatus phytase gene(fphyA) was constitutively expressed in tobacco and recombinant enzyme was secreted from plant roots into the rhizosphere using the signal sequence from tobacco calretieulin.After 40 days of plant growth in hydroponic media,phytase activities in leaves,stems,roots and growth media of transgenic plants were 8.6-fold,7.4-fold,12.6-fold and 14.3-fold higher than those of wild-type plants.Signifi-cant improvements in plant growth and phosphoms(P)utilization were observed in the transgenic plants.When phytate was supplied as the sole P source.45-day-old transgenic tobaccos accumulated 1.0-fold and 0.5-fold more shoot and root biomass than wild-type tobaccos.with a concomitant of 1.7-fold increase in total P concentration.These results indicate that secretive expression of the A.fumigatus phytase improves acquisition and use of P from phytate in plants.     

中亚热带优势灌木根系对土壤抗剪切力的影响

在浙江南部的山体滑坡、泥石流易发区,对中亚热带常绿阔叶林中3种优势灌木植物(檵木、麂角杜鹃和香港黄檀)根系进行野外和室内剪切测试,探讨了灌木植物根系增强土壤抗剪切强度的作用。结果表明:须根相对丰富的植物能明显提高表层土壤的抗剪强度;根系抗拉力和抗剪力均与根径呈幂函数正相关关系;檵木和麂角杜鹃根系抗拉强度与根径呈幂函数负相关关系,而香港黄檀根系抗拉强度与根径无明显相关性;细根或比粗根更有利于土壤加固和抗剪强度的提高。     

植物根系吸水模型研究进展

根系是植物获取水分的主要器官,它直接影响整个植株的输水量以及生命活动。在水资源短缺的状况下,了解根系生长过程中的需水特性并提高农业中水资源的利用率,一直是节水灌溉技术中研究创新的热点。因此,在研究过程中需要对植物根系的吸水量进行精确估算,建立根系吸水模型是定量化研究植物根系吸水特性的重要方法。本文概述了根系吸水的原理及其主要影响因素,对不同研究方法下的根系吸水模型进行分类研究,并阐述其适用范围及优缺点,同时介绍了水盐共同胁迫下的根系吸水模型。最后对目前的根系吸水模型进行分析,提出了今后的研究方向,为构建水稻根系三维动态吸水模型提供了基础。     

内蒙古温带草地低级根生物量格局及其与环境因子的关系

为了揭示根系生长策略与环境的关系以及草地植物根系周转对土壤碳的贡献, 在内蒙古荒漠草地、典型草地以及草甸草地设置17 个样点, 分析总根生物量、低级根生物量和低级根占总根生物量之比随草地类型与土层深度的变化及其与气候、土壤因素之间的关系。结果表明: 1) 低级根生物量与总根生物量正相关, 低级根生物量和总根生物量都与年均降水量、土壤氮含量正相关, 与年均温为负相关; 2) 低级根占总根生物量之比总体上呈现荒漠草原(14%)<典型草原(20%)<草甸草原(39%)的趋势, 与年均降水量正相关, 与年均温负相关, 与土壤全碳和全氮不相关; 3) 低级根生物量随土层的垂直分布规律与总根生物量一致, 在草甸草地随着土层加深而降低, 低级根主要分布在0~40 cm 表层土壤中(85%以上), 而在典型草地与荒漠草地则土层之间差异不显著。研究得到以下结论: 1) 草地植物根系可能通过不同机制响应温度和降水这两个环境因子; 2) 植物在水分贫乏的生境中可能通过降低对快速周转的低级根的投入来减少碳支出, 而投入更多的高级根来存储水分养分, 同时表明干旱生境中植物细根的水分养分吸收效率可能高于湿润生境。     

Rapid assessment of acid phosphatase activity in the mycorrhizosphere and in arbuscular mycorrhizal fungal hyphae

A pot experiment has been carried out under controlled conditions to study the possibility of applying the technique ofin vivo staining for acid phosphatase activity on the roots of mycorrhizal plants and arbuscular mycorrhizal hyphae. The pots had 5 compartments. The central root compartment was separated from the two adjacent hyphal compartments using nylon nets of 30 μm mesh, and the two hyphal compartments were separated from the two outermost compartments with 0.45 μm membranes. Red clover was grown in the root compartment and was either inoculated with the arbuscular mycorrhizal fungus (AMF)Glomus mosseae or unlnoculated. Sodium phytate was applied to all compartments. The results show that AMF can increase acid phosphatase activity of clover roots. The plant roots acquired deep red “mycorrhizal prints”. The external hyphae also had obvious “hyphal prints” on the test papers, indicating the ability of mycorrhizal hyphae to release acid phosphatase.     

植物根系构型的生态功能及其影响因素

植物根系构型即根系在其生长介质中的生长与分布,直接影响着植物的生长和发育.通过概述植物根系构型的基本概念以及生态作用,总结影响植物根构型的诸多因素,主要包括根系的生物学特性、自然条件和人工干扰.基于当前的研究现状,提出了植物根系构型需进一步研究的问题.     

氮磷肥对西南桦无性系生物量分配和根系形态的影响

【目的】西南桦(Betula alnoides)具有较高的经济价值和生态效益,是中国热带、亚热带地区重要的乡土速生阔叶树种。氮和磷的有效性和空间分布显著影响着植物生长和根系发育。笔者研究施肥对西南桦无性系生物量分配和根系形态的影响,筛选出优良西南桦无性系及适宜的施肥配方,为西南桦的科学培育提供参考。【方法】以西南桦4个无性系(编号分别为A5、FB4、FB4⁺、BY-1)组培苗为试验材料,采用完全随机区组设计,每个小区 25 株。设置氮(0、200、400 mg/株)和磷(0、70、140 mg/株)共9个组合处理,重复 3 次。以不施肥为对照。为防止苗木缺素,每株施钾量为332 mg。磷肥作为基肥一次性施入基质中,组培苗移栽成活1个月后,开始追施氮和钾肥,每次施肥间隔时间为7 d,共10次。最终苗木收获时,先分离出根系进行形态指标扫描,获得根长、根表面积、根体积和根平均直径,最后全株烘干用于测定各器官的生物量,比较不同施肥处理下西南桦无性系的生物量分配和根系形态差异。【结果】①不同无性系和施肥处理下西南桦幼苗的地上、地下和总生物量差异均达到显著水平,但无性系×施肥处理的交互作用不显著。施肥处理幼苗的地上、地下和总生物量较对照(不施肥)有明显的增幅。处理5(N 200 mg/株+P 70 mg/株)幼苗的地上、地下和总生物量最大,分别比其他施肥处理提高了11.27%~460.49%、7.14%~200.00%、10.57%~390.09%。进一步比较不同无性系,无性系FB4⁺的地上、地下和总生物量表现出明显的生长优势,分别是无性系A5、FB4和BY-1的1.14~1.21、1.22~1.31、1.15~1.22倍。②不同无性系和施肥处理下幼苗的根表面积、根平均直径和各根径等级细根的根长差异显著或极显著,且无性系×施肥处理的交互作用对根体积、根表面积、根平均直径和各根径等级细根(根径d>2 mm除外)的根长影响均极显著。施肥处理的幼苗根系形态参数均高于对照。在所有无性系中,处理5的根系形态参数均显著高于其他施肥处理,其根表面积、根平均直径、根体积和总根长,分别比其他施肥处理提高了0.77%~227.20%、2.13%~152.63%、0.60%~264.13%和4.53%~214.04%。进一步比较不同根径等级细根的根长,西南桦幼苗的小细根(0<d≤1 mm)、粗细根(1<d≤2 mm)和粗根(d>2 mm)的根长亦表现出处理5最大。无性系FB4⁺在处理5下的根系形态参数显著高于其他无性系和施肥组合。③总生物量与地上、地下生物量均呈极显著的正相关关系,这三者与根平均直径、总根长、根表面积、根体积亦分别表现为极显著的正相关关系。【结论】施肥显著促进了西南桦幼苗的生物量和根系生长发育,且存在无性系差异。综合幼苗的生物量和根系形态指标,认为西南桦无性系FB4⁺在处理5(N 200 mg/株+P 70 mg/株)条件下生长表现最优。     

Molecular mapping of QTLs for root response to phosphorus deficiency at seedling stage in wheat (Triticum aestivum L.)

Phosphorus (P) deficiency in the soil is one of the major abiotic stresses that limit plant growth and crop productivity throughout the world. Development of cultivars with improved P-deficiency tolerance is an efficient strategy for sustainable agriculture. Plant roots play an important role in crop growth and development, especially in nutrient uptake and improvement of P-efficiency. Mapping quantitative trait loci (QTLs) for root traits and their response to low P stress at seedling stage will facilitate the development of P-efficient wheat cultivars. In this study, 30 QTLs (LOD>2.0) were mapped for the three root traits, such as root length, root number and root dry matter under different P supply conditions and their response to P-stress. These QTLs were distributed on 14 chromosomes, with each of the 5 QTLs explaining more than 10% phenotype variance. Analyses showed that root traits and their response to P-deficiency were controlled by different QTLs. In addition, alleles with positive effects were separated on both parents, and wheat cultivars with improved P-efficiency could be developed by accumulating these positive effect alleles together.     

水稻缺铁胁迫条件下根部形态及电镜观察

为研究缺铁胁迫条件下植物的适应机制,首次使用植物凝胶培养方法对不同条件下的水稻根进行形态学观察,结果发现苗期水稻缺铁诱导的根毛和侧根明显增多,幼根周围有分泌物出现.进一步利用电镜制样技术和超薄切片技术在透射电子显微镜下观察两种处理的水稻根尖细胞中膜泡的分布和形态.发现缺铁培养的水稻根尖细胞中膜泡的个数较多,而且较明显.为水稻在适应缺铁胁迫下根部细胞内膜泡运输增强提供了证据.     

北疆高产棉花根系生长规律的研究Ⅱ栽培措施对根系及地上部生长的影响

在北疆大田条件下 ,研究种植密度、灌溉、覆膜等栽培措施对棉花根系与地上部生长影响的结果表明 ,棉花根系具有较强的自动调节能力 ,群体根量在生育前期与密度呈正相关 ,生育后期密度间差异不显著 ;此外根系开始发生调节的时间早于地上部。生育期间干旱胁迫后 ,根量减轻、地上部衰老加快 ,根系生产力下降 ,籽棉产量降低。覆膜的棉花根系建成提前。棉花根量同地上部生物量及籽棉产量间存在显著的线性相关关系     

柽柳根系构型对干旱的适应策略

本文分析了塔里木河下游2个不同林龄柽柳(Tamarix spp)根系的构型参数,以了解柽柳对干旱的适应策略.结果表明:1)柽柳的根系拓扑结构受生境和林龄的不同而存在差异,表现为四年生柽柳的根系分支模式接近叉状分支,一年生柽柳根系的分支更趋于鱼尾形分支,且远离积水区一年生柽柳根系的拓扑指数较近积水区一年生柽柳大,根系分枝更简单,表明一年生柽柳在受到水分胁迫时会通过降低根系分支来适应干旱.2)不同生境、林龄的柽柳均表现出长的根系连接长度,但远离积水区较近积水区的一年生柽柳根系连接长度有增加趋势,表明干旱可以促使一年生柽柳根系伸长生长.3)较小的总分支率是柽柳根系的分支特点.一年生柽柳和四年生柽柳根系的分支率存在差异,一年生柽柳较小的主根分支和较大的逐级分支率有助于资源的获取速率和促进主根的向下生长.四年生柽柳主根分支较丰富,逐级分支率由主根向低级根逐级减小,一方面可以满足柽柳对资源的需要,同时通过长的连接长度可以避免根系的重叠和根系间资源的竞争.     

Molecular mapping of QTLs for root response to phosphorus deficiency at seedling stage in wheat (Triticum aestivum L.)

Phosphorus (P) deficiency in the soil is one of the major abiotic stresses that limit plant growth and crop productivity throughout the world. Development of cultivars with improved P-deficiency tolerance is an efficient strategy for sustainable agriculture. Plant roots play an important role in crop growth and development, especially in nutrient uptake and improvement of P-efficiency. Mapping quantitative trait loci (QTLs) for root traits and their response to low P stress at seedling stage will facilitate the development of P-efficient wheat cultivars. In this study, 30 QTLs (LOD>2.0) were mapped for the three root traits, such as root length, root number and root dry matter under different P supply conditions and their response to P-stress. These QTLs were distributed on 14 chromosomes, with each of the 5 QTLs explaining more than 10% phenotype variance. Analyses showed that root traits and their response to P-deficiency were controlled by different QTLs. In addition, alleles with positive effects were separated on both parents, and wheat cultivars with improved P-efficiency could be developed by accumulating these positive effect alleles together.     

柄扁桃根系水分共享特性研究

研究了沙地灌木柄扁桃根系的水分共享状况．结果表明，柄扁桃根系具有水分共享的潜力,在土壤水分分布不均匀的条件下，若主根水分相对丰富而侧根水分相对匮乏，则水分可以由主根转移到侧根中；若侧根水分相对丰富而主根水分相对匮乏，则水分可以由侧根转移到主根中，主根中的水分可以进行反向运输；若土壤水分分布均匀，则根系水分由侧根向主根转移，在主根中水分由形态学上端向下端转移，以保证对地上部分的水分供应．     

模拟酸雨对水芹根部NH4+、NO3-、H+离子通量的影响

氮素是植物生长发育必需的营养元素,利用水生植物吸收水体中的氮素是富营养化水体生态修复的重要途径。以水芹(Oenanthe javanica)为研究材料,在中富营养和超富营养两种水平下,探讨模拟酸雨对水芹根部H+、NH4+和NO3-离子流及根系活力的影响。结果表明,酸雨对水芹根系吸收水体中氮素产生影响,并随富营养化水平提高其影响加大。分析发现:(1)水芹对NH4+有吸收偏好;(2)与对照相比,模拟酸雨降低了根部H+的外排,相应地减弱了NH4+的内流,增加了NO3-的外排,但对根系活力无显著影响;(3)超富营养水平下,酸雨对水芹离子流的影响增强,并使根系活力显著降低。     

Change of water use efficiency and its relation with root system growth in wheat evolution

Raising crop water use efficiency (WUE) is the physiological basis to implement crop high efficiently using water. The present soil column and field experiments are designed to investigate the change of wheat WUE (Triticum aestivum L.) at whole plant level and root system growth in evolution and the relationship between WUE and its root system growth using 10 wheat evolution genotypes with different ploidy chromosomes sets. Results show that in wheat evolution from 2n→6n, WUE at whole plant level increases with the increase of ploidy chromosomes, and root system growth (root weight, root length) and root/shoot ratio of wheat decrease with the increase of ploidy chromosomes under dry and irrigated conditions. WUE is negatively correlated with root weight and root/shoot ratio of wheat in evolution, significantly. Root system growth has an adverse redundancy for WUE in wheat evolution, and the root redundancy reduces with the increase of ploidy chromosomes, which result in the increase of wheat WUE at whole plant level.     

氮素营养对园林植物根系生长与生理特性影响的研究

以落叶松、橡胶树等园林植物和大田作物为基础,阐述了园林植物根系在氮素营养条件下发生的一系列形态与生理变化。在一定施氮浓度下,随着施氮浓度的增加,园林植物根鲜重、干重逐渐增加,根系总表面积、侧根数、根冠比增大,根系变细变长;不同施氮时期的影响也较为显著,其中早施氮肥对根系生长有利;对根系而言,硝态氮效应比其他形态的氮素效果好;同时,一定的施氮量可以明显增加根系吸水量和根系活力,增加根系分泌物质量,促进碳氮代谢,减少根系内游离氨基酸的数量,维持根系内氮素代谢的平衡。     

富贵竹提取液对几种植物插条生根的影响

利用易生根植物─—富贵竹的水或甲醇提取液浸泡绿豆、扶桑、露水松和毛杜鹃的插条，可增加插条的不定根生成数目，影响生根范围和最长根长度；甲醇提取液可提高绿豆、露水松和扶桑插条的生根范围．除毛杜鹃外，以基部提取液处理插条对不定根的促进作用最好．