【作者】 石强；

【导师】 李德志；

【作者基本信息】 华东师范大学 ， 生态学， 2008， 硕士

【摘要】 植物构筑特征可以反映植物的生产性能。本实验探讨了棉花的形态可塑性、叶片格局分布、茎叶动态变化等特性，试图从这几方面探讨棉花高产的构筑特性和高产调控方法。主要结果如下：一、棉花占据空间的特性：在生育期内具有好的长势，在群体最大时期植株能够充分占据空间，并且茎、叶能够对太阳辐射、对疏密不同的空间做出适应性响应，是群体充分利用环境资源的表现之一。最明显的标志是群体可以形成适宜的结构。1．植株所占据的空间不同（株行距不同），各生育阶段的长势不同，才可能形成高产的群体结构。本实验中，密度为5×10⁴株／hm²，长势旺，小区产量高。蕾期LAI最大日增长量为0．156，节长和最快增长阶段日增长量为1．5cm（现蕾初期-现蕾盛期）；花铃期-吐絮期LAI日增长量0．092。密度为25．6×10⁴株／hm²，长势较弱，小区产量也较高。蕾期LAI最大日增长量为0．03，节长和最快增长阶段日增长量为1．4cm（现蕾初期-现蕾盛期）；花铃期-吐絮期LAI日增长量0．012。衡量棉花生长的关键时期可以通过形态可塑性大小来推断。可塑性最大的时期是棉花生长的关键时期。棉花叶片的分枝叶面积可塑性大小，可用于判定棉花的生长情况。长势正常的植株在吐絮期的单株分枝叶面积≥720cm²。它与单株铃数的关系为：单株分枝叶面积在720cm²-2000cm²，单株结铃数y=-13．2424+3．10068ln（x）；单株分枝叶面积在2000cm²以上，单株结铃数y=2．7078+0．005182x-8．37148E-07x²+1．02373E-10x³（式中，x-单株分枝叶面积）。2．植株的茎叶能够占据稀疏空间时，单株的生产能力强。在株行距确定的条件下，长势旺盛的植株，能够通过枝叶生长占据稀疏空间（行间）；长势弱的植株，可能会被长势旺的植株挤入行间。当植株的光照和通风条件得到改善时，植株的生产能力得到提高。3．当棉花叶片的倾角、光叶夹角、方位角能对太阳辐射做出适应性反应时，自身潜力能够得以发挥。在结铃盛期和结铃末期，至少有两个叶片角度指标能够对太阳辐射角度变化做出响应时，单株结铃数多。4．用Lewis-Leslie模型可基本模拟和反映棉花在打顶前LAI的动态变化趋势。该趋势可以作为了解棉花群体变化特性的参照。二、棉花结构特性当棉花茎叶形成一定的空间结构时，有利于充分利用太阳辐射、CO₂等资源。1．叶片的聚集分布：叶片聚集类别数与不同尺度呈幂指数关系。单株叶片及其聚集成的不同层次的类别数越多，单株结铃数也越多；满足幂律关系的范围越大（如7．3-28．4cm），该范围的初值越大（即叶片平均直径较大），小区产量越高。2．叶片的分形结构：当棉花封行后，单株、群体叶片的分维值（容量维或关联维）较大（如D₀=1．751或D₂=2．294）但两者相差不大、无标度区较大（如单株6．5-28．9cm，群体8．9-52．5cm），且群体无标度区范围大于单株无标度区范围和单株冠层幅宽时，棉花产量较高。3．叶片的格局分布：单株和群体叶片分布格局规模较大（如叶片数格局≥14cm，叶面积格局≥32cm），是棉花丰产的特性。如果存在多尺度格局，更有利于棉花生产潜力的发挥。4．单株冠层特性：当在棉花结铃盛期，单株冠层幅宽较大（不同密度群体的适宜冠层幅宽不同，如对于低密度群体，单株冠层幅宽68．7cm，对于高密度群体，32．9cm）、冠层垂直高度大（如对于低密度群体，冠层垂直高度64cm，对于高密度群体，42cm），从结铃盛期到结铃末期冠层幅宽和垂直高度变化小、冠层形状比率在1左右时，单株结铃数多。三、植株生长调控调控棉花植株生长主要采取水肥调控的方法。由于棉花是覆膜栽培，在苗期底墒充足或降水较多的情况下，会导致表层土壤水分过多影响根系生长。由于地膜的提墒作用，导致浅层土壤水分偏高，这不利于苗期根系向下生长，且容易导致蕾期或初花期植株抗旱能力下降，甚至表现出缺水伤害，因此需要提前灌水。在棉花蹲苗后，灌水量逐次增大，有利于棉花从缺水状态进入正常需水状态。根据棉花的生长状况，三种灌水方式[棉花前期灌水量少（73．6mm，现蕾中后期-盛花期前），灌水量每次逐渐增加；中期（结铃盛期）灌水量大（20天左右灌水144mm）；后期（结铃末期-吐絮期）灌水量小（30天左右灌水量108．4mm），每次灌水量逐渐减少]，对主茎叶面积、分枝叶面积、株高、茎粗、结铃数和单铃重等的提高都有积极意义。氮肥对棉花前期生长作用明显。当前期施氮肥多（尿素450kg／hm²）时，对株高、主茎叶面积、分枝叶面积等有促进作用；施氮肥少（尿素150kg／hm²）时，蕾铃脱落增加；施氮量适中（尿素300kg／hm²）时，落叶少。当后期施氮肥量低时，对株高增长有利，有助于减少叶片脱落。在蕾期施用磷肥有促进主茎叶面积增加的作用；在开花期施磷肥量居中（三料300kg/hm²）时，有利于主茎叶面积增大。施磷肥量大（三料450kg/hm²）时，则植株增高明显。施磷肥量居中时，蕾铃脱落减少，主茎叶片数、主茎绿叶数等指标增加。在现有栽培条件下，以下措施有利于提高棉花产量：灌水量为3600m³／hm²或360mm，密度为5×10⁴株/hm²（籽棉产量：0．5617kg/m²）或17．8×10⁴株／hm²（籽棉产量：0．6227kg／m²），氮肥（尿素）为300kg／hm²，磷肥（三料磷肥）300kg／hm²，缩节胺67．5g／hm²，打顶在初花期至盛花期。更多还原

【Abstract】 Plant architecture can reflect the productivity of plant. In this paper, the characteristics of morphological plasticity, foliage distribution pattern and the dynamics of stem and leaf growth were studied. The characteristics of high-yield architecture of cotton population and the regulation methods were analyzed. The main results are as follows:1. The spatial characteristics of cotton populationThe performances of cotton population taking full advantage of environmental resources are such as good way in growth, fully occupation of space, active responses of stem and leaf to solar radiation and different space, among which the most obvious sign is the structure formed by cotton population.（1） When cotton plants can occupy different spaces and have different growth rates at different growing satges, they tended to form high-yield population structure. This experiment showed that when population density was 5×10⁴/hm², cotton plants grew quickly and the population yield was high. The maximum increment of LAI per day was 0.156 in the bud stage of cotton. The biggest increment of the sum of internodes per day was 1.5cm from the beginning to the peak of bud stage. The increment of LAI per day was 0.092 from the blooming period to the wadding stage. When population density was 25.6×10⁴ /hm², the cotton was growing slowly but the population yield was high too. The maximum increment of LAI per day was 0.03 at the bud stage. The biggest increment of the sum of internodes per day was 1.4cm from the beginning to the peak bud of stage. The increment of LAI per day was 0.012 from the blooming period to the wadding stage.The degree of morphological plasticity might be used to infer the critical period for cotton growth. When morphological plasticity showed biggest degree, it might be regarded as the critical period for cotton growth. The morphological plasticity of leaf area of branch might be used to judge the cotton growth. If the leaf area of branch per cotton plant was not less than 720cm² at the wadding stage, the plant might be regarded as normal in growth.The relationship between the number of bolls and the leaf area of branch per cotton plant was y= -13.2424+3.10068ln（x）, when the leaf area of branch per plant was between 720cm²-2000cm²; and y=2.7078+0.005182x-8.37148E-07x²+1.02373E-10x³, when the leaf area of branch per plant was more than 2000cm² （here, y: the number of bolls per plant; x: the leaf area of branch per plant）.（2） When the stems and leaves could occupy the sparse space, the productivity per plant was high. When the distances between rows and plants were determined, the plants that grew quickly could occupy the space between rows by the growth of stems and leaves, whereas the plants that grew slowly tended to hedge the competition from the strong plants and grew in the sparse space. When the situations of illumination and ventilation were improved, the productivity increased.（3） When the leaf inclination angles, azimuth angles, angles between leaf and solar ray could adaptively respond to the solar radiation, the potential of productivity of cotton plant could be played. When at least two indices of leaf angles responded to the angles of solar radiation, cotton plant could bear more bolls at the peak boiling stage and the late boiling stage.（4） LAI dynamic trend before topping could be simulated by Lewis-Leslie model, which could be used as a reference for understanding the changes of the characteristics of cotton population.2. The structural characteristics of cotton populationWhen the stems and leaves of cotton plants formed certain spatial structures, solar radiation and carbon dioxide could be fully used.（1） Aggregate distribution of foliage. The relationship between the number of category of leaf assemblage and the scales was power exponential function. When there were more number of category of assemblage of leaves and layers, the number of bolls per plant tended to be more. When the range that met the relationship of power exponential function was broad, such as 7.3-28.4cm, and the initial value （i.e. the mean diameter of leaves） of the range was big, the plot yield tended to be high.（2） The fractal structure of foliage. When the values of fractal dimensions of single and population were big, such as D₀=1.751 or D₂=2.294, and the difference between them was small, and the scale invariant range was broad, such as 6.5cm-28.9cm for the single plant and 8.9cm-52.5cm the population, and the scale invariant range of the population was wider than that of single plant and the canopy breadth of single plant. the plot yield tended to be high.（3） The foliage distribution pattern. When the scales of distribution patterns of leaves of single plant and population were big, such as not less than 14cm for the pattern of number of leaves, and not less than 32cm for the pattern of leaf areas, the plot yield tended to be high. If there was a multi-scale pattern, the potential of productivity of cotton population tended to be played fully.（4） The canopy characteristics of single cotton plant. When the canopy width was broad, such as 68.7cm for the population with lowest density, and 32.9cm for the population with highest density, the vertical height of canopy is high at the peak boiling stage, such as 64cm for the population with lowest density, and 42cm for the population with highest density, and the changes of width and vertical height of canopy were small from peak boiling stage to late boiling stage, and crown shape ratio was about 1, there tended to be more bolls per plant.3. The control of growth of cotton plantThe main methods used to control the growth of cotton plants were water- and fertilizer-control methods.Since cotton plants were cultivated under plastic film mulch, if soil water storage or rainfall was enough during seedling stage, surface soil would contain too much water affeting the growth of root system. The coverage of plastic film increased the surface soil moisture, which inhibited the growth of root system deeply and decreased the drought-resistant ability of plants, and even damage the plants. In this case, irrigation should be carried out in advance. After hardening of seedlings, gradually increased irrigation helped cotton plants grow up from water-scarcity state to normal state of water demand. According to the stages of cotton growth, using three irrigation methods increased the leaf areas of the main stems and the branches, stem height, diameters of the stems, number of bolls and single boll weight.The effects of nitrogenous fertilizer to the growth of cotton was obvious in the initial period. The application of more nitrogenous fertilizer, such as 450kg/hm² for urea, promoted the growth of stem heights, leaf areas of the main stems and of branches at the initial period of cotton growth. The application of less nitrogenous fertilizer, such as 150kg/hm² for urea, the shedding of buds and fruits increased. The application of suitable amount of nitrogenous fertilizer, such as 300kg/hm² for urea, the falling of leaves decreased. When applying less amount of nitrogenous fertilizer at the late growing stage, promoted the growth of stem height and decreased the falling leaves.The application of phosphate fertilizer promoted the increase of leaf areas of the main stem at the bud period. At the blooming period, when applying phosphate fertilizer at the medium level, the leaf areas of the main stem increased, whereas when increased the application of phosphate fertilizer, the stem height increased obviously. When applying phosphate fertilizer at the medium level, the number of shedding buds, total leaf and green leaf of the main stems increased.At the present cultivation conditions, the following treatments might promote the yield of cotton: irrigation: 3500m³/hm² or 360mm water, population density: 5×10⁴ /hm² or 17.8×10⁴ /hm², nitrogenous fertilizer （urea）: 300kg/hm², phosphate fertilizer （double superphosphate）: 300kg/hm², DPC: 67.5g/hm², date of topping: from the beginning of blooming period to the peak blooming period.更多还原