Based on the field experiments with different plant-type wheat ( Triticum aestivum ) cultivars and varied population densities, the time-course changes in the angle between stem and sheath (stem-sheath angle) on main stem were observed, and a process-based model was developed for simulating the growth dynamics of stem-sheath angle on the main stem by using system analysis method and dynamic modeling technology. The stem-sheath angle increased with the growth of corresponding leaves, and decreased with increasing population density. The maximum stem-sheath angle decreased with increasing leaf position, except for the first leaf on main stem. The growth dynamics of stem-sheath angle could be described with Logistic equation, and the changes in the maximum stem-sheath angle with leaf position could be quantified with two different equations. The maximal value of stem-sheath angle at the second leaf position was considered as the cultivar parameter to reflect the genetic differences, and the plant number per unit area was used to quantify the effects of population density. The independent field experiment dataset of different wheat cultivars was used to test the model, and the average RMSE between estimated and observed values was 1.7°, suggesting that the present model had good performance and reliability on predicting the growth dynamics of wheat stem-sheath angle, and provided a key module for wheat plant-type simulation and visualization.

基于不同株型品种和不同密度处理的小麦田间试验，连续观察并记录各处理不同叶位叶鞘与主茎之间的夹角，进一步利用系统分析方法和动态建模技术，构建基于过程的小麦叶片茎鞘夹角的动态模拟模型.结果表明：小麦茎鞘夹角随叶片生育进程不断加大，并随密度的增大而减小；从第2叶开始，最大茎鞘夹角随叶位的增加而减小.所建模型利用Logistic方程描述叶片茎鞘夹角随生育进程的动态变化过程，使用分段函数描述最大茎鞘夹角随叶位的动态变化，引入品种参数（第2叶茎鞘夹角的最大值）量化了茎鞘夹角在不同品种之间的差异，并利用基本苗量化了密度对茎鞘夹角的影响.基于独立的田间试验资料对所建模型进行测试与检验，结果显示茎鞘夹角模拟值与观测值之间的均方根差为1.7°.表明模型对小麦主茎叶片茎鞘夹角的动态变化过程具有较好的预测性，为小麦生长过程的可视化表达奠定了技术基础.

【Objective】This study was designed to explore the dynamic changing characteristics of wheat (Triticum aestivum L.) plant type index and the effects of planting density on plant type index.【Method】Based on the field experiments with three cultivars (Aikang 58 with erect leaf, Yangmai 12 and Yangmai 16 with flat leaf) and three planting densities in wheat, the time-course measurements were carried out on the indices of leaf type and stem type at main growing stages of wheat, and then the dynamic changing patterns of plant type indices and the effects of planting density on the dynamics of plant type indices in wheat were analyzed and simulated.【Result】The results indicated that the layer LAI of different plant-type cultivars had a trend of “middle layer> upper layer> lower layer”, and the layer LAI was gradually concentrated in the middle or upper layer with the growing progress. In addition, the larger LAI of the middle or upper layer was observed on high population density. The significant differences of plant height component index (the ratio of the length of rachis and penultimate internodes to plant height, IL) between high and low population densities were observed. The plant height component index (the ratio of the length of n internode to the length of n internode adding (n-1) internode, In) of different plant-type cultivars were all decreased first and increased later from lower to higher leaf positions. In addition, the remarkable effect of planting density was observed on In of upper internode. As for Aikang 58, a relatively constant LOV with a slight “up-down-easing down” trend was observed. As for Yangmai 12, the change pattern of LOV was in “gentle-decrease-gentle” trend. As for Yangmai 16, a trend of “gentle-decrease-increased slightly” was showed. Based on the analysis of plant type index dynamics and the existing morphological model, the dynamics of layer LAI was simulated by using the methods of canopy cutting and leaf area integration, and the dynamics of the plant height component index and LOV were simulated by using combined morphological parameters. In addition, the comprehensive plant type component index was constructed by integrating different morphological indices, and reflected the dynamic changes of the leaf type and stem type synthetically. Testing of the dynamic models of layer LAI, plant height component index and LOV with independent dataset showed that the average RRMSE values of layer LAI and LOV were 17.44%, 7.64%, and 10.66%, respectively.【Conclusion】The results indicated a good performance and reliability of models for predicting plant type index in wheat. The model can not only provide technical supports for the simulation of canopy structure in wheat, but also lay a foundation for the simulation of light distribution and photosynthesis within wheat canopy.

【目的】揭示小麦株型指标变化规律及播种密度对株型指标的影响。【方法】基于不同播种密度和不同株型品种的小麦田间试验，通过连续观测主要生育时期小麦主茎叶型和茎型指标，分析并模拟分层叶面积、叶向值、株高构成指数等株型指标的动态变化规律及播种密度对其的影响。【结果】不同株型品种分层叶面积指数（LAI）均表现为中部>上部>下部的分布特征，并随生育期的推进逐渐向中上部集中，且冠层中上部总是高密度群体LAI较大。所有品种高低密度间株高构成指数（穗下节与倒二节间长度之和与株高的比值，IL）均表现出显著差异，不同株型品种株高构成指数（n节间长与n节间加n-1节间长度之和的比值，In）表现为从下至上先减小后增大的趋势，且上部节间受密度影响较大。较为紧凑的矮抗58叶向值在不同密度下表现平稳，随生育进程略微表现为增大—减小—趋缓的趋势；较为披散的扬麦12号中高密度下随生育进程均表现为平缓—减小—平缓的趋势；扬麦16号则表现为平缓—减小—略微增大的趋势。在分析株型指标变化趋势和课题组已有形态模型的基础上，通过冠层切割和叶面积积分的方法模拟了叶面积指数的分层动态变化，利用组合的形态参数模拟了株高构成指数和叶向值的动态变化，并通过对形态指标的归类分析，构建了综合性株型构成指数，综合体现了叶型和茎型的动态变化。利用独立试验资料对分层叶面积指数、株高构成指数和叶向值的动态变化模型进行了检验，其平均RRMSE分别为17.44%、7.64%和10.66%。【结论】经检验，该模型对上述小麦株型指标具有较好的预测性。

Based on extensive observations and quantitative analysis on leaf sheath and internode growth processes with different variety types, a dynamic model was developed to simulate time-course growth characters of leaf sheath and internode in wheat. The growth

以5个不同株型小麦品种为供试材料,通过对冬小麦品种叶鞘和节间生长过程的连续观测和定量分析,构建了小麦叶鞘和节间生长过程的动态模拟模型。模型采用Logistic方程描述了叶鞘和节间的伸长动态;利用叶鞘与对应节间长度的比例关系模拟了不同节间的长度;利用节间粗与对应节间长的比例关系定量描述了不同节间的粗度。模型检验结果显示,不同叶鞘长、节间长和节间粗预测值的平均RMSE值分别为1.34、1.71和0.06 cm,表明本模型具有较好的预测性和可靠性。

形态可视化技术足虚拟植物研究的关键技术之一.本研究以小麦作物 为对象,在提出小麦形态可视化技术框架的基础上,首先研究了小麦不同器官的三维几何建模技术,构建了基于器官形态特征参数的儿何模型,包括叶、茎秆和麦穗 几何模型.用NURBS曲面来模拟叶片和叶鞘;用圆柱体模拟茎秆的节间;并采用组合单器官的方式来构建麦穗模型:用圆柱体模拟穗轴,用椭球体和域柱体分别 模拟小穗的谷粒及小穗枝梗.然后,基于OpenGL,图形平台,绘制了小麦器官的三维彤态,并提出了颜色渲染、纹理映射、光照处理等真实感图形显示技术; 最后,通过耦合小麦植株的拓扑结构模犁以及小麦个体之间的相互关系,实现了小麦从器官-个体-群体三个层次的形态可视化,从而为构建可视化小麦生长系统奠 定了技术基础.

Crop organ morphological model is one of the key technologies of virual crop. By observing and analyzing the morphological and topological structures of wheat spike, the morphological parameter-based 3D geometric model and visualization method were developed. Based on the existing morphological model of spike in wheat, the 3D morphological geometric model of wheat spike was constructed by integrating the topological structure of spike, including the submodels of ear axis, spikelet (including outer bran, awn and anther) and spike shape. The ear axis was constructed by connected proglottids which were represented by slant cylinder. Based on the surface vertical curve, the outer bran was simulated by approximate semiellipsoid with triangular faces. The awn, with transversal surface as nearly equilateral triangular, was constructed by triangular faces based on the curve of awn. The anther on the top of floret in flowering stage was simulated with NURBS surface. In addition, the spike shape was controlled by using hierarchical model. Then according to the topological structure, the above organ models were organized together to rebuild the whole 3D geometric model of wheat spike. By further integrating the rendering models of color, texture and light, the visualization of growth dynamic of wheat spike was realized based on the platform of Microsoft .Net and CSOpenGL graphic library. The reconstructed geometric model with three dimensions can simulate visualization of growth dynamic of wheat spike under different varieties and treatments. The result will be helpful to realizing the realistic simulation of wheat plant, and the digitalization and visualization of growth dynamic of wheat.

作物器官几何建模是虚拟作物研究的关键技术之一。通过对小麦穗形态结构的观测分析，提出基于形态特征参数的麦穗几何模型及可视化实现方法。在已有麦穗形态模拟模型的基础上，结合麦穗拓扑结构，构建麦穗形态结构几何模型，包括穗轴、小穗（外麸、麦芒、花药等）、麦穗穗形等子模型。其中，穗轴节片使用底面为椭圆的圆柱体进行模拟，节片交错叠加构成穗轴。基于外麸曲面半径变化曲线，以三角面片构造近似半椭球体来模拟外麸；基于麦芒曲线，以三角面片重构横截面近似为等边三角形的麦芒；用非统一有理B样条曲面模拟开花期小花顶端的花药；采用分层模型控制麦穗穗形。然后根据麦穗拓扑结构组合以上各器官，即可构建出麦穗几何模型。进一步结合颜色渲染、纹理映射、光照渲染等真实感显示技术，基于.Net平台，借助CSOpenGL，实现麦穗生长动态的可视化。结果表明，重构出的麦穗具有一定的真实感，能够用于不同品种、不同处理条件下麦穗生长动态的可视化表达。研究结果将有助于实现小麦植株生长动态的数字化、可视化。

 In order to deepen the studies of crop models (CMs), promote its development, and make it to join into international development tide, the methods of systematic analysis, classification, comparison, and mining of epistemology, etc were adopted in this paper. The roles in CMs were set forth through definition and classification of CMs, and the relationships between CMs and digital plant (DP) were analyzed in this paper. The latest studies and application progresses of CMs in China and overseas were reviewed, the issues in their current studies and application were analyzed through comparison of differences in plant growth models among four research groups (DSSAT, School of de Wit, APSIM, and China) and in functional structural plant models (FSPMs) among three research groups (L-Studio, GREENLAB, and China) in the world, and some countermeasures and suggestions for their further development were proposed. At present, although the application of CMs and DP is little, it will have a wide development and application foreground with development of agriculture in China in future, especially, changes in proportion of town and countryside.

为进一步深化与促进作物模型发展，并融入国际潮流，论文以系统学思想为指导，采用系统分析、分类、比较及认识论挖掘等方法，通过作物模型概念、分类、作用及其与数字种植业的关系分析，阐述了作物模型的作用，综述了国内外作物模型研究与应用新动态，比较了国际上作物生长模型四大研究组（DSSAT，School of de Wit，APSRU及中国）和功能-结构植物模型三大研究组（L-Studio，GREENLAB及中国）间作物模型的差异，分析了存在问题，提出了进一步发展的对策和建议。目前，虽然作物模型在数字种植业中的应用较少，但随着中国农业的发展，特别是城乡结构的变化，未来它将具有广阔的应用和发展前景。

摘　要： 【目的】构建基于生物量的水稻叶片主要几何属性模型,为水稻株型设计与调控提供理论依据。【方法】以两优108、86优8、南粳43及扬稻6号为材料,设置品种、氮肥与密度田间试验,观测水稻主茎不同叶位叶片长度和宽度,分析了水稻主茎叶片长和宽的关系、比叶重（SLW）随叶位的变化规律,以及水稻叶片干重与叶长和叶宽的关系,构建基于生物量的水稻叶片主要几何属性模型。【结果】叶长与叶宽的关系可用幂指数方程表达,比叶重随叶位呈二次曲线变化。采用独立的试验资料检验模型,主茎叶片叶长、叶宽模拟值与实测值的根均方差（RMSE）分别为2.55和0.06cm。【结论】几何属性模型可较好地模拟不同生长条件下水稻主茎不同叶位叶片的主要几何属性,为生长模型与形态结构模型的结合奠定了基础。

Maize plant morphology directly influences its eco-physiological function (e.g. biomass production). With the morphology of organs changing as newly produced biomass is allocated into the organs, the maize eco-physiological function is continually modified during each new stage of plant growth and development. In order that maize growth and development be more accurately simulated, we present a maize model which integrates plant architecture and physiological function. We emphasize the development of organ ...

探讨了基于玉米器官生物量模拟其形态的方法 ,并应用 2 0 0 0年田间试验数据提取了玉米节间、叶鞘和叶片的形态构建参数。基于玉米虚拟模型生物量分配模块模拟的器官生物量积累和建立的形态构建方法与提取的参数 ,模拟了 2 0 0 1年玉米不同生长阶段的器官形态 ,模拟结果与田间试验数据吻合较好。应用本模型实现了玉米生长过程中植株各个器官形态变化以及植株高度、叶面积动态的模拟 ,并实现了植株形态的可视化。

【Objective】 The aims of this study were to build the biomass-based main geometric parameter dynamic models of rice root system according to the relationships between the total root length, the total root volume, the total root surface area per plant and the dry weight per plant of different rice cultivars under different fertilizer levels. 【Method】 Three rice cultivars, ‘Liangyou108’ (Hybrid long-shaped rice, V1), ‘86you8’ (Hybrid round-shaped rice, V2), and ‘Nanjing43’ (Round-shaped rice,V3), were planted in pots with two fertilizer levels: fertilizer (N:3.6 g/pot, P2O5:0.8 g/pot, K2O:3.6 g/pot) , and no fertilizer (with loamy soil) to obtain the root system morphological characteristics, the dry weight, etc., which were processed by SPSS v13.0 and Excel 2007. The models developed in this paper were verified using RMSE.【Result】The biomass-based dynamic models of the total root length were set up through analyzing relationships between the total root length and the biomass per plant from the experimental data in 2008, and then, the biomass-based dynamic models of the total root volume and the total root surface area per plant also were developed according to the principles of solid geometry, which were tested by using the experiment data in 2009. The results showed that the RMSE between the simulated values and the observed values of the total root length, the total root volume, and the total root surface area per plant were 490.660 cm/plant, 131.859 cm2/plant, and 2. 532 cm3/plant, respectively. 【Conclusion】 The models developed in this paper were reliable with mechanics, general adaptability, and interpretative characteristics in a certain extent, which would lay a basis for developing Functional-Structure Rice Models.

【目的】建立基于生物量的水稻根系主要几何参数动态模型,为水稻功能-结构模型的研究奠定基础。【方法】于2008和2009年设置3个品种[两优108（V1,杂籼）、86优8（V2,杂粳）和南粳43（V3,常规粳稻）]和2个氮肥水平盆栽试验获取根系形态及根干重等指标,采用SPSS v13.0与Excel 2007处理试验数据,RMSE检验模型。【结果】利用2008年观测资料,通过分析不同品种与施肥处理下水稻单株总根长及根直径与生物量间的定量关系,建立了基于生物量的水稻单株总根长动态模型;根据立体几何原理,构建了基于生物量的水稻总根体积与总根表面积动态模型。经2009年独立试验资料检验,单株总根长、总根体积及总根表面积的实测值与模拟值的RMSE分别为490.660 cm/plant、131.859 cm2/plant和2.532 cm3/plant,说明模型拟合度较好。【结论】所建水稻根系主要几何参数模型具有一定机理性、解释性和通用性,对水稻功能-结构模型研究及水稻可视化奠定了基础。

Three-year experiments with different planting densities were conducted in Anyang, Henan Provence of China. The development and morphogenesis module of COTGROW model was improved based on the allometry relationship between biomass and morphology, which was used to construct cotton model for above-ground organs. The morphology model included several sub-models, such as stem, leaf, petiole, boll, and so on. A visual cotton growth process was displayed through linking the COTGROW and the GroIMP models, thus, the cotton canopy light interception was simulated. The results showed that the dynamic change of each organ size could be characterized by relationship between biomass and morphology based on cotton above-ground organs model of COTGROW. The model was validated by independent experiments in 2010. The root mean squared error (RMSE) between the measured and simulated values for morphological parameters were 3.85, 0.64, 0.52, 0.66, 1.00, 0.15, 1.58, 2.39, 2.54, 0.05, 0.13, and 0.10 cm for plant height, nodes on main stem, the number of fruiting branches, nodes on different fruiting branches, internode length, internode diameter, leaf length, leaf width, petiole length, petiole diameter, boll length and boll diameter, respectively. Various 3D morphology of cotton plant in different environmental conditions and different plant densities was shown, and light interception of canopy also well simulated. Functional and structural model for above-ground organs in cotton could be used to simulate cotton morphological characteristics and display the real growth process of organs and plant, which provides a technical basis for virtual farming.

利用 2008 — 2010 年棉花密度试验 , 分析棉株器官生物量 - 形态间异速生长关系 , 改进 COTGROW 模型中的发育和形态发生模块 , 构建了棉花地上部器官形态建成模型 ; 基于 COTGROW 模型模拟数据 , 与 GroIMP 可视化开发平台的数据链接 , 实现了棉花生长过程的可视化 ; 利用建立的功能 - 结构模型对不同密度棉花冠层的光截获量进行了模拟。利用 2010 年的试验数据检验模型 , 结果表明 , 棉花株高、主茎节数、果枝数、各果枝果节数、节间长度、节间直径、叶片长度、叶片宽度、叶柄长度、叶柄直径、棉铃长度以及铃直径测定值与模拟值间的均方根误差分别为 3.85 、 0.64 、 0.52 、 0.66 、 1.00 、 0.15 、 1.58 、 2.39 、 2.54 、 0.05 、 0.13 和 0.10 cm , 模型效果较好 ; 构建的棉花地上部功能 - 结构模型可以较好地模拟棉花的形态特征 , 并较逼真地显示棉花器官、植株的三维动态生长过程 , 可以反映出不同环境条件、不同密度处理下棉花植株的三维形态 , 在可视化的基础上模拟棉花冠层空间的光截获量。为虚拟棉作研究提供了技术基础。

At first, the thesis introduced social background, scientific values and economic significances of researches for plant morphological structure simulation and visualization, secondly, reviewed its progresses in found and development, collectivity trends and characteristics, institutions and scholars with world advance level and its sign, collectivity level and gap and causes analysis of formation in china, front fields and blank points and weakness taches, et al., lastly, its prospects and some policy suggestions were put forward.

本文较系统阐述了植物形态结构模拟与可视化研究的社会背景、学术价值和经济意义，从创立与发展、研究与发展的总体趋势和特点、研究居世界先进水平的机构或学者以及领先标志等方面综述了植物形态结构模拟与可视化的研究进展；指出了该研究的前沿领域、空白点及薄弱环节，分析了中国在该研究中的总体水平、差距及其成因；最后在研究展望基础上提出了若干政策建议。

本研究在国内外相关研究的基础上，基于2011-2012年不同 品种和氮素水平试验、2012-2013年不同品种以及不同品种、氮素和密度试验，运用系统学原理和数学建模技术，综合油菜各器官形态生长过程与生物量之 间的定量关系，构建了基于生物量的油菜越冬前地上部、分枝叶片等形态结构模型。主要研究结果如下: 　　1.建立了油莱越冬前植株地上 部形态结构模型 　　基于2011-2012年田间试验，在考虑氮肥因素影响的基础上，结合油菜叶片比叶长重 (Ratiooftheleafbladelengthtoleafbladedryweight，RLW)、干重分配系数 （partitioningcoefficientofbladetoplantdryweig...

小麦植株形态建成的模拟模型，对实现小麦生长的可视化表达具有重 要的理论意义和应用价值。本研究基于小麦生长发育规律，以热时间为主线，通过连续观测不同氮肥水平下不同类型品种小麦地上部器官的形态特征，综合研究了不 同处理条件下小麦主要器官生长发育的动力学过程及其受氮素因子的影响，构建了小麦植株主要器官形态建成的模拟模型，具有较好的解释性和预测性，从而为进一 步建立虚拟小麦生长系统奠定了基础。 本研究以不同氮肥水平下不同类型小麦品种的两年田间试验为基础，通过连续观测不同处理条件下小麦主茎和分蘖叶片形态指标(包括叶长和叶...

根据冬小麦根系分布的试验测量参数与生长规律,综合考虑根系生长的生理生态模型和虚拟植物模型,构造了描述小麦根系生长的动态模型.在已建立的根系生长模型基础上,运用分形几何理论与计算机图形学技术,对耕作土壤环境下冬小麦根系构型进行了三维仿真模拟.根据根系实测参数,对冬小麦根系生长模拟进行宏观控制,可以真实再现冬小麦地下根系部分的动态生长过程.

对不同类型冬小麦品种叶形空间分布参数进行了定量描述,建立了叶片形状、叶面积指数随生长期的变化、叶面积随高度的分布及叶倾角分布(LAD)等叶形空间分布的模拟模型及推理系统,提出了叶片形状因子和长势模拟模型,单叶空间最高点、高度层间隔内累积投影叶面积及各组分的空间取向与叶倾角分布解析模型系统及其主要设计算法.上述模型为具有普适意义的冬小麦冠层结构机理模型,其推理系统可以精确计算任意高度层次的投影叶面积分布特性,是评价作物株形结构优劣判断群体结构合理与否的有力工具,同时对于解析和利用多角度遥感数据监测作物长势等也具有重要参考价值. Abstract： Leaf structure parameters of different types of wheat varieties were quantitatively described, and analytic models and a deduction system for simulation of wheat leaf shape and LAI development along with growth stages established. The system can analyze single leaf vertex and cumulative projection leaf area for different wheat height intervals, interspace directions and leaf angle direction distributions. The models can be used for description of winter wheat canopy structure. The deduction system can be used for precise calculation of cumulated projection leaf area for specific height intervals and integrated evaluation of plant shape. The deduction system can also be used in analysis and application of multi-angle remote sensing data to monitor crop growth status.

Taking thirty six wheat cultivars bred in different era and ecological regions as test materials, their seedlings growth under water stress was investigated, and their drought resistance was evaluated by gray correlation grade analysis. Significant difference was observed in the drought resistance among the cultivars. The weighted drought resistance index ranged from 0.6580 to 0.2434. Among the test seventeen morphological and physiological traits, shoot dry mass had the greatest correlation degree (0.9473) with drought resistance, while SPAD had the smallest one (0.5356). The test cultivars were clustered into three groups, among which, eight cultivars belonged to strong drought resistance group, twenty three cultivars belonged to medium drought resistance group, and five cultivars belonged to drought-sensitive group. The shoot dry mass, root dry mass, plant dry mass, plant height, root nitrogen accumulation, leaf area, and tiller number per plant differed significantly among the three groups, which could be used for evaluating the drought resistance of wheat cultivars at seedling stage.

以36个不同育成年代和生态区域的小麦品种为材料，研究了水分胁迫对小麦苗期生长的影响，并基于灰色关联分析评价了小麦品种苗期抗旱性的基因型差异.结果表明：小麦品种抗旱性差异显著，加权抗旱指数在0.2434～0.6580之间；17个形态生理性状中与抗旱性关联程度最大的是地上部干物质量(0.9473)，最小的是叶绿素含量(0.5356).采用聚类分析将36个小麦品种分为3类，其中抗旱型8个、中间型23个、敏感型5个.3类基因型的地上部干物质量、根干物质量、植株干物质量、株高、根系氮积累量、叶面积和单株分蘖数差异显著，可作为小麦品种苗期抗旱性鉴定的直接指标.

The effects of different sowing dates and varieties on development stages of wheat were studied in this paper.The results showed that the emergence of tiller was mainly regulated by the ecological factors rather than the genetic effect.For winter-type variety(Jing 411),most variable growth duration throughout the entire growth cycle occurred from tillering to jointing. In contrast,the timing of single ridge stage was determined by genotypic effect rather than ecological factors.Single ridge to double ridge stage was most sensitive to vernalization progress.For spring sowing of winter-type variety,the vernalization process could last till floral primordium differentiation stage. The corresponding relationships existed between phenological and spike development stages in different sowing dates,although a little variable. Winter-type variety had more ecologically variable leaf primoudia,due to its stronger vernalization requirement. For winter-type variety,the primordium numbers of reproductive organs were not apparently related to the GDD accumulated prior to vernalization completion,while for spring-type variety(Yangmai 158),the numbers of different apex primordia including vegetative and reproductive organs were significantly related to the accumulated GDD during the entire phenological stages as well as before anther separation stage.

以热时间(thermal time)为尺度研究了小麦不同品种和播期对发育阶段的效应.结果表明,小麦分蘖发生的早晚以生态因子调控为主,基因型差异较小;分蘖拔节期为冬性品种(京411)一生中可变性最大的生育阶段.穗分化进入单棱期的早晚以基因型效应为主,生态因子的影响次之;单棱二棱期为春化作用的敏感期,冬性品种晚播(3月2日)春化效应可延迟到小花原基分化期之前.小麦物候期与穗发育阶段的对应关系具有一定的可变性.冬性品种较强的春化作用增加了其生态可变叶原基数;春化过程结束前,物候发育及穗发育阶段累计GDD与相应生殖器官原基分化数的相关性不明显.春性品种(扬麦158)的物候发育及药隔分化期之前的穗发育阶段与各类顶端原基的分化数均具有极显著的正相关关系.

正 在小麦栽培过程中,其低位蘖尤其是第一分蘖往往长不出来,形成分蘖“缺位”现象。由于低位蘖成穗率高,所以缺位现象严重的麦田,每亩成穗数少,产量低。所 谓分蘖“缺位”,就是按照叶、蘖同伸规律,应长出的分蘖没有长出来。对于分蘖缺位现象已有报导,但尚缺少较为系统的研究。因此,进一步研究分蘖缺位的原因 和控制其产生的途径,提出降低低位蘖缺位率的具体栽培术措施,对提高中、低产区小麦生产具有理论

To model the geometry of individual plant or organ, B-splines were used to simulate maize leaf and compute the leaf characteristics of geometry with virtual model. The method needs less parameters and achieves higher precision than other methods, and is a good way for geometry modeling in maize leaf.

针对虚拟作物研究中的作物个体或器官几何造型问题，用三次B样条来拟合玉米叶片的三维形态，并用虚拟模型进行玉米叶片几何特征的计算。与其它方法相比，该方法具有精度高，参数少的特点，是一种适合于玉米叶片三维造型的好方法。

为了精确重构小麦三维空间形态,增强几何模型与品种特性及作物模型间的衔接,通过对小麦植株拓扑结构和形态结构的观测分析,对叶片、穗、茎秆等地上部器官几何造型算法进行了研究.结果表明,小麦叶脉曲线可用比叶重、叶倾角和叶长3个参数确定,进一步与叶形和叶片边缘几何造型模型整合,能够对小麦叶片生长、卷曲以及扭曲等进行精确描述.在麦穗几何造型中,使用偏圆柱体重构穗轴节片,以二次曲面代表颖片、稃片,可以实现麦穗的参数化建模.通过定量化小麦植株拓扑结构和器官的形态特征参数,采用结构化建模途径,在VC++6.0集成开发环境和OpenGL图形平台上驱动器官几何模型,可以快速精确重构出不同生育时期的小麦三维形态,并实现可视化显示,重构出的小麦植株具有较强的真实感.因此,基于形态特征参数的小麦地上部器官几何造型算法能够较好地实现器官及植株的精确重构,且易于交互、可控性强.

根据玉米叶片三维形态特征,应用悬臂梁模型来描述玉米叶曲线,对描述玉米叶片边缘扭曲的数学模型进行改进后,提出了基于特征参数的玉米叶片三维形态数学模型及其实现方法.本模型大大减少了描述全米叶片三维形态的信息量,并具有较高的逼真性,同时适用于描述其它禾谷类作物叶片的三维形态.

Through close observation and research on the morphological formation, as well as growth rules of corn leaf, and combined with some knowledge in agriculture the mathematic model for changes on morphology in corn leaf was brought forward. By the meanings of techniques of Computer Graphics, VC++ and OpenGL, the 3-Dimensional Visualization of leaf morphological formation was realized on computers. The advantages of the model are as follows: the structure is simple, it is apt to be interactive, the images produced on computer with the model has high Sense of reality; and it can simulate the growing process of the corn leaf very well on computer.

为了更好地进行玉米叶片几何造型模拟，基于对玉米叶片形态建成过程的观测研究，首先提取了玉米叶片形态结构和形态建成过程的主要特征，然后构建了参数化的玉米叶片几何模型。该模型用较少几个具有较明确的生物学意义的形态参数，就可实现玉米叶片形态和形变过程的矢量化，再结合VC 和OpenGL，就可在计算机上重现玉米叶片的虚拟生长，模拟结果表明，图像上的效果、产生的数据和实际叶片基本一致，从而为相关领域研究者提供了一个可视化的玉米叶片模型。该模型结构简单、易于交互、真实感强，可较好地模拟玉米叶片建成过程中的形态变化特征。

With the development of computer graphics and crop simulation, virtual crop study, intuitionally expressing crop growth on computer, attracted many scientists to focus on this field. Some scientists have made great progress on the visualization of wheat, maize, soybean, rice and cotton, etc. Leaf shape is a very important characteristic in virtual crop growth modeling, and some empirical curves have been used to describe leaf morphology based on field experiments in the previous study. The fitting curves can help to understand organ morphogenesis, but the fitting parameters obtained from the given leaves and time cannot suit to changed growth process of leaves. So developing a mechanism model to simulate the leaf morphology is critical for virtual crop growth. Organ morphogenesis of plant is decided to its forces. After force analysis on a rice leaf, the gravity fraction in leaf normal direction keeps equilibrium with elasticity, and then a dynamic leaf curvature equation was deduced with some assumption. The equation included the synthetic effect of leaf blade length, leaf blade width, initial leaf angle, specific leaf weight and deformation coefficient on leaf space shape. Then the equation was solved with parameterization. The sensitivity analysis showed that the equation could well reflect the integrated effects of leaf length, leaf width, specific leaf weight and leaf deformation coefficient, consistent with rice plant architecture in practice. A field experiment was conducted at the Nanjing Agricultural University for validating the equation. Two cultivars (SU63 and WYG7) were nursed in dry-bed on May 20, and transplanted on June 20 with single seedling. Water and nutrients were supplied according to high yielding rice management. At jointing and booting stage of rice, the 3-dimension coordinates of several points in leaf midrib were measured with the 3D digitizer, and at the same time leaf blade length, width, initial leaf angle were obtained. Then simulation analyses were conducted on the equation with the experiment data. The results indicated that the leaf curvature equation could reasonably and reliably describe the change pattern of leaf shape characteristics of rice under different conditions. The leaf curve equation could dynamically simulate the space shape of leaves with different initial leaf angles and special leaf weights by reduced parameters of rice leaf, especially in modeling day-to-day crop growth.

通过对水稻叶片的受力分析，推导了叶曲线方程，并进行了影响系数的参数化和方程求解。对叶曲线方程的灵敏度分析表明，方程较好地体现了叶长、叶宽、叶形、比叶重和叶片形变系数等参数对叶曲线的综合影响，与生产中水稻株型特征变化相一致。进一步利用三维数字化仪获得的不同品种类型水稻拔节期和孕穗期叶脉空间坐标试验数据对叶曲线方程进行了模拟分析，结果表明叶曲线方程可以合理而可靠地定量描述水稻叶曲线特征的动态变化规律。