As an important organ of absorbing water and nutrients for crops, root system architecture (RSA) has become a bottleneck in-depth study of crop roots due to the observing obstacles of soil. Three dimensional and visualization are important methods for studying and recognizing the morphological and structural traits of plants. In the aspect of crop root phenotype, these methods have a significance for characterizing the growth appearance of roots and for the influence of water, nutrients and other substances in the soil on RSA. In this paper, from the three dimensional perspective, the research progresses in detecting methods, three dimensional reconstruction and visualization of RSA in recent years were reviewed. Destructive and in situ detection methods of RSA were introduced. Destructive detecting methods mainly include (i) direct mining, (ii) protective soil block mining and cleaning, (iii) root scanning and image analysis, etc. These destructive methods have great advantages in obtaining global or local topology and extracting the plane geometric parameters. Meanwhile, in situ method mainly include six classes: (i) installation of root observation windows in field, (ii) ground penetrating radar, (iii) cultivation in controllable environment, (iv) CCD camera imaging, (v) 3D digitizing and (vi) X-ray computed tomography (CT), etc. These in situ methods retained the distribution information of RSA in space. However, most of the in situ detecting methods are only available for young or grown in controllable environment roots. Because a great deal of the detected data of RSA exist in the form of two-dimensional image, studies on extraction and analysis of plane geometry RSA parameters from two dimensional images were introduced as well, including root identification and parameter extraction algorithms and manual extraction software. Analysis showed that, the crop root data acquisition still exist some problems, such as time-consuming and laborious, redundant limitations, low integrity, difficult to integrate of each other, etc. Therefore, detecting and analyzing morphological traits of roots will still be the focus of RSA research. On the basis of RSA detecting technology, 3D modeling and visualization methods of RSA were reviewed on the aspects of 3D static modeling and dynamic growth simulation. 3D static modeling of RSA includes two kinds of methods: 3D modeling based on simulating algorithms and 3D reconstruction based on in situ detecting. Combining the computer simulation algorithms and understanding of RSA, the 3D modeling methods using simulating algorithms construct virtual roots with high morphological similarity of the real one. In contrast, 3D reconstruction based on in situ detection, which mainly includes XCT and 3D digital methods, could reflect the actual morphological structure of the RSA. Finally, the paper prospected the research on 3D reconstruction of crop roots under the condition of data missing. It was considered that 3D measurement and analysis of root topology could be realized using current technical means, while the 3D reconstruction of spatial distribution of RSA was difficult, especially in the premise of in situ measurement of crop roots in field. In addition, current 3D root data mainly have the data missing and low integration problems, so it is necessary to introduce the statistical methods like small sample theory and data fusion method into the research of 3D reconstruction of crop root to achieve a better reconstruction strategy by using multiple RSA data effectively in the premise of data missing.

根系是作物获取水分和养分的重要器官,由于土壤的观测阻碍,根系三维形态的认知与表达成为作物根系深入研究的瓶颈。三维数字化、可视化是研究和认知作物形态结构的重要方法,研究具有表征根系长相长势及土壤中水分、养分等物质对作物根系构型的影响具有重要意义。本文从三维角度,综述了近年来作物根系构型探测手段、三维重构与可视化方面的研究进展。首先从破坏性探测与原位探测两方面介绍了近年来根系构型三维探测的方法。破坏性探测主要包括直接挖掘法、土块保护挖掘清洗法和平板扫描图像分析法,破坏性探测方法在获取全局或局部根系拓扑结构与平面几何构型参数方面具有较大优势；原位探测方法主要包括土壤中安置观察装置法、地面穿透雷达法、特殊培养环境法、CCD相机法、三维数字化方法及穿透射线成像法等,作物根系的原位探测保持了根系构型的空间分布信息,但大部分方法仅能针对作物生长初期或可控生长环境下的作物根系开展数据获取。由于作物根系探测数据大多以局部二维图像形式存在,文章综述了基于二维图像的作物根系平面几何构型解析的相关内容,包括基于二维图像的根系识别与参数提取的算法与相关软件。分析表明,目前作物根系数据获取仍存在：（1）数据获取费时费力；（2）方法局限性大；（3）数据完整性低；（4）各种方法所获取数据融合应用度低等问题。在根系探测的基础上,从三维建模与生长建模两方面介绍了作物根系三维建模与可视化方面的相关工作。其中,根系三维建模包括了基于模拟算法的几何建模和基于原位探测的三维重建两部分,基于模拟算法的几何建模是在人们对作物根系认识的基础上,结合计算机模拟算法,构建与实际根系具有形态相似性的根系三维几何模型；与之相比,基于原位探测的三维重建更能真实地反映作物根系的实际形态,其主要包括XCT、三维数字化等方法。最后,文章展望了数据缺失条件下的作物根系三维重建研究,认为在目前技术手段前提下,已可实现根系拓扑结构三维解析,但根系的空间分布重建难度较大,尤其是在大田环境下作物根系原位测量的前提下；此外,目前作物根系三维数据主要存在着数据缺失、各种数据各为己用等问题,认为有必要将小子样理论与数据融合相关方法引入到作物根系三维重建研究,实现缺失数据条件下有效利用多种数据获取手段的作物根系三维重建。

为实时获取浅根系作物的根系生长形态，设计了一种可用于多点测量的微型根系形态实时原位采集系统。系统主要由微型摄像头和光学放大元件等组成（体积1.5 cm3），采集的图像通过无线模块发送至终端。采用基于区域生长的根系图像分析方法，以腐蚀图像为出发点，膨胀图像为终止点，结合相似性准则进行区域生长、区域标记和区域保留，来滤除土壤孔隙和杂质等对图像产生的干扰，从而提取根系轮廓，并通过图像形态学计算得到根长密度、根系平均直径等形态参数。以此系统采集樱桃番茄、辣椒根系形态参数，试验结果表明，根系长度测定值的绝对误差不超过1.5 mm，相对误差不超过5.3%；根系平均直径绝对误差不超过0.09 mm，相对误差不超过6.7%。与土壤采样法测定值相比，在0～10、>10～20、>20～30和>30～40 cm 4个土壤层内2种测定方法根系平均直径决定系数R2>0.87（P 0.81（P<0.01）。证明本文设计的微型根系形态实时原位采集系统具有较高的准确性，可用于浅根系作物形态的多点观测。

In order to clarify the mechanism of nitrogen,potassium and their interactions on sweet potato growth,we utilized sand culture methods and made four treatments:CK,N,K and NK and explored the effects of nitrogen,potassium and their interactions on nutrients uptake,agronomic traits,root development,NR,SS,SPS and ADPGPPase of sweet potato.The results showed that N treatment significantly increased the shoot and root nitrogen content;SPAD value,leaf number,leaf area of sweet potato; total root length,root surface area,root average diameter and root volume,NR activity,SS activity and SPS activity were 5.9%,12.1%,1.9%,3.6%,14.1%,13.6% and 19.5% higher in N treated plants than in CK plants;ADPGPPase activity in N treated plants was 7.1% lower than in CK plants.Compared with CK,N treatment's tubers rates were decreased by 7.9%,while the proportion of middle-root (root only waste nutrients) was increased by 7.7%.Compared with CK,K treatment significantly increased the shoot and root potassium content,root activity,total root length,root surface area,root volume and root mean diameter,SS activity,SPS activity,ADPGPPase activity were increased by 16.2%,28.2%,10.1%,39.3%,12.6%,14.9%,20.1% and 14.5%.Compared with CK,K treatment's fibrous roots and tubers were increased by 0.2% and 12.4%;while the proportion of middle-root was decreased by 12.6%.Compared with N and K treatments,respectively,NK had interactive effects on the growth of shoot and root of the sweet potato and increased the proportion of fibrous roots and tubers,significantly promoted the tuber formation.The table of two-factor analysis showed that NK treatment exist significant positive interaction effects on shoot and root nitrogen and potassium content,root activity,root diameter,NR activity,SPS activity,ADPGPPase activity.The results revealed the interaction mechanisms of nitrogen and potassium from the root morphology and shoots two enzyme changed and provided a theoretical basis for high yield and quality of sweet potato cultivation.

为阐明氮、钾营养及其交互作用对甘薯分根结薯期根系分化及叶片酶活性的影响,采用砂培研究方法,设氮钾正常供给(正常)、多氮(N)、多钾(K)和氮钾配施(NK)4个处理。探讨了氮、钾及其交互作用对甘薯苗期养分吸收、农艺学性状、根系发育、硝酸还原酶(NR)、蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS)和腺苷二磷酸焦磷酸化酶(ADPGPPase)的影响。结果表明,与氮钾正常供给处理相比,N处理显著提高了甘薯地上和地下部氮吸收量、SPAD值、叶片数、叶面积;N处理总根长、根表面积、根体积、平均直径和NR活性、SS活性和SPS活性分别提高了5.9%,12.1%,1.9%,3.6%,14.1%,13.6%,19.5%,而ADPGPPase活性降低了7.1%;另外N处理块根比例减少7.9%,中等根(徒耗养分的根)分化比例升高7.7%。与氮钾正常供给处理相比,K处理显著提高了地上和地下部氮吸收量,且K处理根系活力、总根长、根表面积、根体积、根平均直径、SS活性、SPS活性、ADPGPPase活性分别提高了16.2%,28.2%,10.1%,39.3%,12.6%,14.9%,20.1%,14.5%;氮钾配施(NK)处理须根和块根分化比例升高0.2%和12.4%,中等根(徒耗养分的根)分化比例降低12.6%。与N和 K处理相比,氮钾配施(NK)处理能够调控甘薯苗期地上和地下部生物量比例(T/R值),同时提高须根和块根分化比例,显著促进了薯块的膨大。双因素分析表明,氮钾配施(NK)对地上和地下部氮钾含量、根系活力、根平均直径、NR活性、SPS活性、ADPGPPase活性均存在显著的正交互效应。从地下部根系形态和地上部酶学变化两方面揭示氮钾交互机制,为甘薯高产优质栽培提供理论依据。

It is important and significant to know the spatial distribution pattern of fine roots for understanding the utilization status of the available resources belowground. The objective of this study was to investigate the fine root dynamics of Caragana korshinskii Kom, a shrub species widely planted to control soil erosion and land desertification in the semiarid area of China, in a 5-year-old plantation in the Loess Plateau area of Northwest Shanxi, China. Using the minirhizotron technique. The minirhizotron tubes were installed at two horizontal distances (0 cm and 50 cm) from the plant stems in the top 100-cm of soil. Based on the data sampled in the growing season (from April to September) of 2009, we analyzed the spatial-temporal patterns of fine root length density ( RLD , mm/cm 2 ) and fine root surface area density ( RAD , mm 2 /cm 2 ) in the plantation, and explored the relationships of RLD and RAD with the environment factors such as air temperature, soil temperature, rainfall and soil water content. The results showed that (1) there were certain differences in both vertical distribution patterns and seasonal change trends of fine roots between the two horizontal sites, and the obvious difference was that the values of RLD in the upper 0-60cm soil layers at the 0cm horizontal site were greater than those at the 50 cm horizontal site, and that the values of RLD ( RAD ) measured in every month for the former were larger than those for the latter. Therefore the RLD and RAD for the former (4.04 mm/cm 2 and 4.67 mm 2 /cm 2 ) were significantly larger than those for the latter (3.07 mm/cm 2 and 2.99 mm 2 /cm 2 ). (2) As a whole (for the average of two horizontal sites), the maximum value of RLD ( RAD ) appeared in 40-50 cm soil layer while the minimum value in 60-70 cm soil layer in the 100 cm soil profile. The RLD ( RAD ) showed a common seasonal trend with the peak value in the middle period of growing season. The total averages of RLD and RAD of fine roots in the growing season were 3.55 mm/cm 2 and 3.83 mm 2 /cm 2 , respectively. (3) For 0 cm horizontal site, 50 cm horizontal site or the average of two horizontal sites (i.e. the plantation), the seasonal change course of RLD was significantly and positively related with air temperature and soil temperature, respectively. The above results showed that the horizontal distribution of the fine roots of young Caragana korshinskii was characterized by appearing mainly around the taproots, and the seasonal change trend of RLD was highly consistent with the change of temperature factor. Although the correlation coefficients between the seasonal change courses of RLD ( RAD ) and water indices (rainfall and soil water content) were not significant, this did not imply that fine root growth was not affected by water factor. Further research is required on the mechanisms of fine root dynamics in the annual growing season because of the internal and external controls of fine root growth.

以晋西北黄土高原区5年生柠条( Caragana korshinskii )人工林为研究对象,应用Minirhizotron技术,分别在距茎干水平距离0 cm和50 cm处设点(以下简称为0 cm位点和50 cm位点),对林地0-100 cm土层深度范围内的柠条细根进行了观测。以2009年生长季(4-10月)的细根根长密度( RLD ,mm /cm 2 )和表面积密度( RAD ,mm 2 /cm 2 )数据为基础,结合同期环境因子(气温、降雨量、土壤温度和土壤含水量等)数据,对0 cm和50 cm两个位点的细根动态特点进行了比较研究。结果表明:(1)两个水平位点的细根垂直分布和季节变化趋势均具有一定差异,主要差异是0 cm位点0-60 cm各土层的 RLD 均大于50 cm位点,前者各测定期的 RLD ( RAD )均大于后者。因此,0 cm位点的细根分布量(4.04 mm/ cm 2 和4.67 mm 2 / cm 2 )显著大于50 cm位点(3.07 mm/ cm 2 和2.99 mm 2 / cm 2 )。(2)就整体(两个位点平均值)而言, RLD ( RAD )的垂直分布以40-50cm土层最大,以60-70cm土层最小。 RLD ( RAD )的季节变化具有由小变大再变小的趋势。年生长季幼龄柠条细根的 RLD 和 RAD 总平均值分别为3.55 mm/ cm 2 和3.83 mm 2 / cm 2 。(3)就0 cm位点、50 cm位点或整个林地而言,细根 RLD 的季节变化与气温和土壤温度的季节变化均具有显著正相关性。以上结果表明,幼龄柠条细根的水平分布具有"近主根"特点; RLD 的季节变化与温度因子的季节变化具有高度一致性。

In order to study the growth rhythm of maize root, a large root monitoring system was used in an experimental filed to analyze maize ('NO. 46 Tunyu') root. The minirhizotron observation method and the quadrate monolith method were used to monitor the main parameters such as maize root length, root length density and root length ratio at milky and maturity stage. Meanwhile, underground glass windows were used to measure root length and width. The results showed that root length density ratios measured by the minirhizotron observation method and the quadrate monolith method were consistent with the increase in soil depth at milky and maturity stage, with correlation coefficients of 0.987 and 0.717, respectively. Root length density ratios estimated by the two methods were highest in 0 20 cm soil layers. The 0 60 cm soil layers were the primary growth zone of fine roots, with average net root length density 4 times that in the 70 220 cm soil layer measured by the quadrate monolith method. Root length densities from the two methods were not significantly different, with a correlation coefficient of 0.830. The horizontal width of roots in the upper soil layer became narrower with increasing vertical depth from milky stage to maturity stage. This suggested that roots still grew during late developmental stage. Differences were noted in root depth between the quadrate monolith method and the underground glass window method, probably due to inconsistent environmental conditions.

为了研究玉米生长后期根系的生长发育规律, 利用中国气象局固城农业气象试验站大型根剖面系统, 采用微根管观测系统及方形整段标本法和地下根系室玻璃窗, 对'屯玉46号'玉米根系的生长状况进行了试验研究。结果表明: 垂直方向上, 方形整段标本法和微根管法测得的根长密度占整层总根长密度比例的变化趋势一致, 相关系数分别为0.987和0.717, 且两种方法在0~20 cm土层的根长密度比例均为最大。0~60 cm土层为玉米根系生长活跃区, 方形整段标本法测得根长密度生长量为其余层的4倍。两种方法测得的根长密度无显著差异, 相关系数为0.830, 均匀性水平较好。玉米成熟期根系的水平幅度较乳熟期窄, 下层根系仍处于生长中, 垂直深度增加。玻璃窗与方形整段标本法观测的根深测定结果存在差异, 这可能与观测环境条件不一致有关。

Difference of nitrogen utilization efficiency and distribution of mineral nitrogen in soil profile by barley/maize, wheat/maize, faba bean/maize intercropping systems and corresponding sole cropping systems with nitrogen application of 0 and N 225 kg/ha were conducted in field microplot experiment. The results indicated that competitive ability of crops for nutrition closely related to the concentration and accumulation of mineral nitrogen in crops root zone. Accumulation of mineral nitrogen under barley and wheat strip intercropped with maize decreased 203-282 and 107-171 kg/ha compared with faba bean intercropped with maize in 0-100 cm soil profile, respectively. Accumulation of mineral nitrogen under maize strip intercropped with barley and wheat reduced 93-120 and 56-87 kg/ha compared with maize intercropped with faba bean, respectively. Crops, interspecific competition and soil condition affected accumulation of mineral nitrogen in soil profile. Interspecific interaction increased nitrogen recovery efficiency for barley and wheat intercropped with maize, however, decreased that for maize intercropped with barley and wheat. Nitrogen utilization efficiency was highest in low soil fertility for competitive intercropping system. Nitrogen harvest index was reduced in barley and wheat with N fertilizer applied, but increased in maize and not changed in faba bean. Crops competition, soil fertility, rate of fertilizer application and cultural measure should be considered carefully in order to achieve intercropping advantage when we choice associated crops. Complement system of legumes/cereals were planted in low soil fertility and competitive system of cereals/cereals in high soil fertility.

田间小区试验，研究大麦/玉米间作、小麦/玉米间作和蚕豆/玉米间作及其对应单作体系，在不施氮和施氮225 kg/hm 2 情况下，对氮素吸收利用效率和土壤剖面无机氮变化的影响。结果表明，作物对养分的竞争能力与其根区土壤无机氮浓度和累积量密切相关。两作物共生期不施氮肥时，0—100 cm土层，土壤剖面无机氮残留量是间作大麦和间作小麦根区分别比间作蚕豆根区减少203～282和107～171 kg/hm 2 ; 与大麦和小麦间作的玉米根区分别比与蚕豆间作的玉米根区减少93～120和56～87 kg/hm 2 。土壤无机氮累积量受作物类型、种间相互作用强度及实时土壤环境条件影响。种间相互作用提高了间作大麦和小麦的氮素当季回收率，但使与其间作的玉米氮素当季回收率降低。大麦/玉米和小麦/玉米竞争体系在不施氮肥时氮素利用效率最高。施用氮肥使大麦、小麦氮素收获指数降低，玉米氮素收获指数升高，对蚕豆无影响。在选择配对作物时，为获得间作优势要充分考虑作物竞争能力、土壤基础肥力条件、施肥水平及配套栽培措施等。低肥力土壤宜选择豆科/禾本科互惠体系，高肥力土壤宜选择禾本科/禾本科竞争体系。