【作者】 李国强；

【导师】 曹卫星；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2011， 博士

【摘要】 良好的小麦株型是获得高产的重要基础,因此,研究并构建小麦高效冠层的调控途径,具有重要的理论意义和应用价值。本研究以不同株型特征的小麦品种(紧凑型高秆宁麦9号、紧凑型矮秆矮抗58、中间型扬麦12和松散型淮麦17)为对象,研究不同施氮水平下,小麦叶型、茎型和群体冠层结构特征的变化规律,以及株型特征与籽粒产量和构成因素之间的关系,并最终提出理想株型的调控途径。本研究以不同氮素水平下、不同株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叶片形态指标(包括叶长、叶宽、茎叶夹角、叶间距等),综合分析了小麦叶片形态指标随生育进程的变化规律,以及氮素和株型对叶片形态的调控效应。结果表明,随着生长度日的逐渐增加,小麦主茎叶片长度和宽度、茎叶夹角、单株叶面积均呈“S”形曲线变化,而叶片SPAD值,至开花期达最高值,随后逐渐下降。随着叶位的增加,小麦叶长和叶宽、茎叶夹角均符合二次多项式曲线,而单叶面积呈“升-降-升-降”的变化趋势。不同株型小麦品种顶部三张叶片的叶型指标差异主要表现在顶部三张叶片的叶长和SPAD值,旗叶与倒二叶间距及倒三叶基角。施氮量对不同株型小麦品种叶型指标的建成过程有显著影响,但对不同品种的影响程度有差异。通过连续观测不同处理条件下小麦株高和主茎节间构成,综合分析了小麦株高及其构成、节间直径和长度随生育进程的变化规律,及氮素和株型对其的调控效应。结果表明,小麦株高随生长度日的动态伸长过程可以采用Logistic方程进行描述。小麦主茎顶四节的节间长大小顺序为：穗下节间>倒二节间>倒三节间>倒四节间,且均以穗下节间最细；紧凑型宁麦9号和矮抗58以倒四节间最粗,而松散型淮麦17和中间型扬麦12以倒二节间最粗。株高拟合方程的参数及衍生参数在不同施氮量和株型间存在显著差异。小麦主茎顶四节间的节间长和节间粗、穗长与施氮量呈正相关。在拔节、齐穗、灌浆和成熟期,施氮量对株高均有显著影响,而在返青期对株高的影响不显著。于齐穗、灌浆和成熟期,施氮量和株型对节间长和直径有显著影响,但对株高构成指数影响不显著。基于不同氮素水平下、不同株型小麦品种叶面积指数、叶面积密度分布、透光率和光合速率等冠层特征的连续观测数据,综合分析了小麦冠层结构特征随生育进程的变化规律,以及氮素和株型对其的调控作用。随生育进程的推进,叶面积指数和群体茎蘖数的变化均呈单峰曲线,且分别于孕穗期和拔节期达到峰值。叶片净光合速率随生育进程先增加后下降,开花期达到峰值,于花后,叶片净光合速率逐渐下降。群体透光率的日变化呈抛物线状,且于14时达到最大值。不同株型小麦品种的叶面积指数、SPAD值、冠层绿叶面积和比叶重均存在差异,但群体茎蘖数差异不显著。于植株定形时,紧凑型品种宁麦9号和矮抗58、松散型品种淮麦17和中间型扬麦12的冠层垂直剖面绿叶面积的分布分别呈中部大上下两端小的直立“椭圆形”、上下基本一致的“柱形”、上小下大的“梯形”和上大下小的“倒梯形”。最大叶面积密度以紧凑型品种矮抗58的最大,中间型品种扬麦12的最小。施氮量对叶面积指数、SPAD值、比叶重均有显著影响。于孕穗期到成熟期,氮素对群体茎蘖数的调控效应显著。随施氮量增加,紧凑型品种宁麦9号和矮抗58的SPADmax、GDDmax、Rinf2和GDDinf2与中间型品种扬麦12和松散型品种淮麦17的变化趋势相反。施氮增加了小麦的茎蘖数、比叶重、净光合速率和最大叶面积密度,且提升了最大叶面积密度所在的叶层高度。通过连续观测和定量分析不同处理下小麦干物质、氮素含量、籽粒产量及其构成,综合分析了不同株型小麦碳素、氮素积累与转运规律,以及籽粒产量构成差异。采用Richards和VP方程准确描述了不同处理下小麦干物质积累及其在不同器官间的分配比例动态。不同株型小麦干物质积累与分配对施氮量的响应差异主要表现在千物质积累的起始生长势、渐增和快增持续期,以及各器官的最大分配比例、分配比例最大下降速率和最大增长速率。不同器官的总糖转运量和转运率大小顺序分别为：茎鞘>叶片>穗部营养体,茎鞘>穗营养体>叶片。施氮量对4个株型小麦品种的叶、茎鞘和穗营养体可溶性总糖转运量的调控作用存在显著差异。不同株型小麦品种的茎鞘、穗营养体和叶片氮素输出量差异明显。施氮提高了4个株型小麦品种的花前氮积累量和成熟期氮积累量,但不同株型小麦品种在花后氮同化量上表现不一致。不同株型小麦产量差异主要来自千粒重和穗粒数,而穗数主要受氮素调节。通过取样观测不同小麦品种和施氮水平下,株型形态特征、冠层结构特征、干物质和氮素积累与分配、及籽粒产量等指标,综合分析了籽粒产量及其构成因素与株型形态特征、冠层结构特征、碳氮积累与转运特征之间的相关关系。籽粒产量、千粒重与旗叶叶片特征呈显著正相关,但与倒二和倒三叶叶片特征的相关性较差；而穗粒数与顶部三张叶片特征均呈显著正相关。籽粒产量、千粒重和穗粒数与穗下节间长和倒四节间长均显著正相关,千粒重与倒二节间长、穗粒数与倒三节间长的相关性也达到显著水平。随生育进程的推进,籽粒产量和穗数与群体茎蘖数的相关性逐渐增强,而千粒重和穗粒数与群体茎蘖数的相关性未达到显著水平。籽粒产量、千粒重、穗粒数和穗数与花后干物质积累量、花前贮存物质转运量和花后物质积累对籽粒产量的贡献率(CPA)呈显著正相关,而与花前贮存物质对籽粒产量的贡献率(CTA)呈负相关。籽粒产量、千粒重和穗粒数与花前贮存物质转运率(TAR)呈显著正相关,而穗数与TAR呈显著负相关。籽粒产量、千粒重、穗数与氮转运量、氮转运率、花后氮同化对籽粒产量的贡献率呈显著正相关,而与花后氮转运对籽粒产量的贡献率呈负相关。在相同种植密度下,株型造成的产量差异是由于花后干物质同化量积累差异造成的千粒重和穗粒数差异。更多还原

【Abstract】 The objective was to establish the regulation approaches of ideal plant type for high yielding. The split plot design was conducted with main plot of nitrogen fertilizer, and sub-plot of wheat cultivars differing in plant types (compact-high stalk type, Ningmai 9; compact-low stalk type, Aikang 58; Middle type, Yangmai 12; loosely type, Huaimai 17). This study focused on the effect of plant type and nitrogen fertilizer application rate on morpho-physiological characters of leaf and stem, canopy structure and light distribution, accumulation and translocation of carbon and nitrogen, grain yield, and the relationships among those characters.The change patterns of leaf morphology with growth progress were characterized based on leaf morphological properties of main stems under different nitrogen rates with four wheat cultivars. The result showed that the trend of leaf length and width, and leaf angle looked like "S" shape with GDD. In contrast, Leaf SPAD increased gradually with GDD and reached the maximum at anthesis, and then decreased slowly. Leaf length and width, and leaf angle exhibited quadratic polynomial with different leaf position. Nevertheless, single leaf area had an "up-down-up-down" trend with leaf position. Leaf characteristics had a remarkable difference between cultivars at major growth stage. Nitrogen rate affected greatly leaf length and width, leaf angle, SPAD, and leaf area just at anthesis and grain filling period. Leaf length and width, leaf angle of different leaf position as affected by plant type and nitrogen rate had not the same response, but SPAD and distance between neighboring leaves of different leaf position had the same response. Difference of top two leaves leaf angle in Yangmai 12 and Huaimai 17 was larger than in Ningmai 12 and Aikang 58. The distance between neighboring leaves associated not only with plant type, but with also plant height. The distance between flag leaf and top 2nd leaf was the main difference of wheat cultivars with different plant type, as well as distance between top 2nd leaf and top 3rd leaf. Nitrogen rate strongly affected leaf length, leaf angle and SPAD, but had no effect on leaf width, leaf area, and distance between neighboring leaves at major growth stage. Nitrogen rate significantly affected leaf length of top three leaves and leaf width of top two leaves, but did not affect leaf width of top 3rn leaf. Nitrogen rate affected length and width of flag leaf more than that of top 2nd and 3rd leaf. Nitrogen rate increased leaf SPAD and leaf angle of top three leaves.The pattern of stem characteristics and the effect of plant type and nitrogen rate on plant height, and length and width of internode was analyzed based on time-course observation on plant height and internode length and width of main stems. Plant height changed like "S" shape, and fitted well to Logistic equation during growing stage. Top four internode length was in the order: internode below ear> top 2nd internode> top 3rd internode> top 4th internode. The 4th internode width of Ningmai 9 and Aikang 58 and the top 2nd internode of Huaimai 17, and Yangmai 12 were the maximum. Nevertheless width of internode below ear was the minimum. Parameters derived from equation of plant height had great difference between nitrogen rates and plant types. Internode length and width correlated positively with nitrogen rate. Nitrogen rate strongly affected plant height at stem elongation period, full heading period and maturity, not yet at returning green. Nitrogen rate and plant type significantly affected internode length and width, but did not affect plant height index. Nitrogen rate and plant type influenced spike length, and nitrogen rate were positively related with spike length. So, there is a significant difference in plant height and internode of different plant type and nitrogen rate. Nitrogen rate greatly increase plant height, internode length and width, spike length.Wheat canopy structure characteristics pattern was analyzed based on time-course observations on canopy characteristics under different nitrogen rates with four cultivars. The result showed that leaf area index and tiller number, which reached the maximum at booting stage and jointing stage, presented a single-peak curve, respectively. Net photosynthetic rate of leaf decreased gradually from flowering. Population light transmittance changed like parabola curves in diurnal course, and reached the maximum at noon. There was a great difference of plant type in LAI, SPAD, canopy green leaf area and specific leaf weight, not yet in population tiller number. The vertical distribution of green leaf area in four cultivars had significant difference. Nitrogen rate significantly affected LAI, SPAD and specific area weight. Nitrogen fertilization had a remarkable difference on population tiller number at booting and harvest. Ningmai 9 and Aikang 58 had a increase trend in SPADmax、GDDmax、Rinf2 and GDDinf2 with nitrogen rate increasing, but Yangmai 12 and Huaimai 17 had a reverse trend. Nitrogen rate enhanced tiller number, specific leaf weight, net photo synthetic rate and maximum leaf area density, and made level of maximum leaf area density gone up.Carbon and nitrogen accumulation and translocation pattern and difference of grain yield in four cultivars were analyzed based on time-course observation on dry matter, nitrogen content, grain yield and its components. The result showed that relative dry matter and proportion of organs to biomass with relative thermal time from sowing fitted better to an Richards model and vapor pressure model, respectively. The dry matter accumulation duration of early stage decreased with nitrogen rate increasing under different wheat cultivars, whereas that of the third stage increased, and that of the second stage obviously differed from cultivars. Although the average growth rate Ra and maximum growth rate Rmax of dry matter increased with nitrogen rate increasing, that of dry matter dry mater decreased when nitrogen rate exceeded 150 kg ha-1, Transfer amount of soluble sugar ranked in the order of stem and sheath, leaf blades, and spike. Translocation rate of soluble sugar ranked in the order of stem and sheath, spike and leaf blades. Nitrogen fertilization affected remarkably transfer amount of soluble sugar in leaf, stem and sheath and spike of wheat cultivars. Nitrogen translocation amount of stem and sheath, spike and leaf in four wheat cultivars had significant differences. Nitrogen increased pre-anthesis nitrogen accumulation and nitrogen accumulation at maturity, but response of post-anthesis nitrogen assimilates in four wheat cultivars to nitrogen fertilization were different.Dry matter and nitrogen accumulation and translocation, grain yield, correlation between grain yield and its components and plant type characteristics, canopy characters, carbon and nitrogen accumulation and translocation were analyzed based on time-course sampling observations. The result showed that grain yield and 1000-grain weight correlated significantly with the characteristics of flag leaf, but did not with that of the second and third leaf. Grain number per spike positively associated with characteristics of top three leaves. Moreover, grain yield,1000-grain weight, grain number per spike positively associated with length of upmost internode and second internode from top.1000-grain weight also significantly associated with length of second internode, and grain number per spike remarkably correlated with third internode. Grain yield and spike number closely associated with stem and tillers number, but 1000-grain and grain number per spike did not correlated with stem and tillers number. Grain yield,1000-grain, grain number per spike, and spike number significantly associated with post-anthesis dry matter accumulation, translocation amount of pre-anthesis stored assimilate, contribution of post-anthesis stored assimilate to grain yield, but had no relationship with contribution of pre-anthesis stored assimilate to grain yield. Grain yield,1000-grainweight and grain number per spike positively associated with translocation rate of pre-anthesis stored assimilate (TAR). Spike number with TAR showed a negative correlation. Grain yield,1000-grain and spike number with nitrogen translocation amount, nitrogen transportation efficiency, contribution of post-anthesis nitrogen assimilation to grain had a positive correlation, and with contribution of translocation amount of nitrogen accumulation to grain had a negative correlation.更多还原