水稻叶龄与叶面积指数动态的模拟研究

 依据不同类型品种的播期试验和氮肥试验结果,建立了水稻叶龄与叶面积指数(LAI)的模拟模型。叶龄模型采用幂函数描述叶片出生与播后累积热时间(TTS)的关系,TTS的计算定量了温度与出叶速率之间的非线性关系。叶面积指数模拟包括两个阶段:在指数生长阶段,LAI随播后累积生长度日(GDD)呈指数式增长,同时受到氮素营养水平调节;当LAI≥1.6时进入非指数生长阶段,采用比叶面积法模拟,LAI是比叶面积与绿叶干物质量的乘积。绿叶干物质量是绿叶分配指数与地上部干物质量的乘积,比叶面积(SLA)为GDD的函数,同时考虑植株氮素营养因子对SLA的影响。利用生态条件和栽培条件差异较大的试验资料对模型进行了验证。结果表明,模型能较好地模拟不同条件下叶片的出生动态和LAI变化动态,表现出较强的适用性,具有参数少、易确定、简便实用的特点。     

华杂6号叶面积简易测定方法

研究了在直播条件下，华杂6号的叶长、叶宽、长宽乘积与叶面积，单叶面积与整株叶面积的关系。结果表明，华杂6号的单片叶面积与叶长、叶宽、长宽乘积都呈幂函数关系，但单片叶面积与长宽乘积关系最密切，其次是叶宽，最后是叶长。单株叶面积与单片叶面积呈一元线性函数关系，但相关性最好的叶片所处叶位，随绿叶数的增加而降低。     

玉米黄绿叶突变体SN62及其光合特性的研究

以中绿叶色的SN12和浓绿叶色的丹340两个玉米自交系为对照,对黄绿叶色突变体SN62的形态特征、叶面积指数、叶绿素含量、光合速率、产量进行比较研究。结果表明,该突变体受1对隐性基因控制;植株发育正常;产量和叶面积指数介于丹340和SN12之间;叶绿素含量明显较低,但光合速率与SN12和丹340差异不大;在生育后期,SN62的光合速率高于两个对照。     

种植密度和施氮量对鲜食糯玉米叶片光合生理特性的影响

不同密度和施氮量下,鲜食糯玉米植株单株可见绿叶数和展开绿叶数、单株叶面积、叶面积指数、光合势、功能叶的叶绿素a、叶绿素b和叶绿素a b、功能叶净光合速率等变化均呈单峰曲线。这些生理指标均随施氮量的增加而增加;除叶面积指数及光合势随密度增加而增加外,其余指标均随密度的增加而下降。     

利用无人机数字图像监测不同棉花品种叶面积指数

叶面积指数是表征作物光合作用能力大小的重要参数。本文利用无人机数码相机获取9个棉花品种全生育期冠层数字图像，基于归一化绿－红差值指数Normalized green-red difference index，NGRDI、 可见光大气阻抗植被指数（Visible atmospherically  resistant  index，VARI）、过绿指数（Excess green index，ExG）、过绿减过红植被指数（Excess green minus excess red index，ExGR）和绿叶植被指数（Green leaf index，GLI）5种常用的可见光颜色指数，通过多阈值分割，提取小区中心部位植被覆盖指数，研究不同植被覆盖指数反映棉花叶面积指数的差异。通过设置相机不同曝光时间筛选出在自动曝光下表现较稳定的基于颜色指数的植被覆盖指数GLI、NGRDI与ExG。然后研究了棉花叶面积指数以及基于GLI、NGRDI与ExG的植被覆盖指数变化规律，以及两者的相关性。结果表明：叶面积指数随播种后时间的增加先增大后减小，花铃期叶面积指数达到峰值；基于 ExG、GLI、NGRDI 的3种植被覆盖指数在生育期内都呈现开口向下的二次曲线；叶面积指数与基于NGRDI、ExG的植被覆盖指数呈显著线性相关，尤其是在吐絮期前，决定系数（R2）分别为0.913、0.912，基于NGRDI的估测效果显著好于ExG。利用基于NGRDI的植被覆盖指数预测试验田叶面积指数并形成分布图。因此，利用无人机搭载普通数码相机获取棉田叶面积指数是可行的，该方法可为指导生产管理提供参考。     

新陆早33号丰产潜力研究

研究了新陆早33号单产皮棉2772kg·hm^-2的叶面积指数、冠层结构、光合速率和干物质积累与分配等特征。结果表明：新陆早33号前期营养生长的速度快、强度大；生育中后期叶面积指数高，且下降慢，高值持续期长，保证了充足的光合面积；叶绿素含量高，保证了光合作用的高效进行；光合产物分配合理且比例高，保证了该品种的高产稳产。     

不同基因型玉米间作研究初报

连续两年(1997～1998)的不同基因型玉米间作试验表明：不同基因型玉米杂交种合理间作有利于高产和稳产。吐丝后叶面积指数大于相应的单作或增加幅度较大，绿叶面积持续时间长，对穗粒数、粒重提高显著，而且田间株高整齐度趋于一致。     

春小麦源库特性及其关系的研究（Ⅰ）——群体源的形成及其特性分析

为了了解春小麦群体源的形成与特性以及群体源在产量形成中的作用,通过试验对不同密度和施肥处理下两个品种的叶片性状变化进行了研究。结果表明,在不同处理下春小麦群体叶面积指数争光合劳均呈单峰由线变化,两个品种间在不同生育阶段的叶面积指数争光合势有差异。随着生育进程的推进,两品种的光合劳与产量相关性增强。在开花期争乳熟期,干物质积累与叶面积指数(LAI)争光合势(LAD)呈显著或极显著正相关,比叶重、叶绿素含量争群体光合速率等叶片性状与群体干物质生产密切相关。因此,在合理的栽培技术措施下,采取适宝的密度与合理的配方施肥技术,建立合理的群体叶面积,将最大叶面积指数控制在适宜的范围内,尽可能长时同地保持绿叶面积,增强叶片光合能力,提高群体生长速率,是扩大干物质(源)生产的主要途径。     

“促稳保”施肥法的生理效应研究

比较了研究了“促保”施肥法“与重底早追”施肥法影响头季和再生稻产量的一些生理指标。“促稳保”在施穗以前，其叶片含氮量，叶面积指一直部干物质积累速度比“重度早追”的低，群体比其小，施穗粒肥后，其叶片含氮量，叶绿素含量，绿叶面积，地上部干物质积累速度和光合作用速率比“重低早追”的高。     

玉米-大豆带状套作中荫蔽及光照恢复对大豆生长特性与产量的影响

大豆在玉米-大豆带状套作模式中经历了荫蔽期和光照恢复期,本研究比较了两个大豆品种(贡选1号、桂夏3号)在带状套作荫蔽期和光照恢复期的生长特性及产量,以期为选择适宜带状套作的大豆品种提供依据。结果表明,在套作荫蔽期大豆表现为地上部干物质、叶面积降低,干物质分配呈"茎增叶减"趋势;贡选1号的干物质在叶中的分配比例显著高于桂夏3号,地上部干物质、叶面积的反应指数均低于桂夏3号。在光照恢复期大豆的地上部干物质、叶面积快速增加,干物质"茎增叶减"的分配趋势减弱;贡选1号的地上部干物质、叶干物质分配比例、叶面积均高于桂夏3号。两个大豆品种在套作下的产量差异不显著,但桂夏3号显著低于其单作对照。套作大豆产量与光照恢复期地上部干物质、叶面积呈正相关。大豆产量在套作下的降低程度与两个时期的地上部干物质、叶面积受影响程度呈正相关。因此,在光照恢复期能积累较多干物质,形成较大叶面积,且荫蔽期生长状态受影响程度低的品种适宜带状套作。     

Simulating Organ Growth in Wheat Based on the Organ–Weight Fraction Concept

Abstract

Quantifying dry matter partitioning into individual organs of plants is a key component for simulating crop growth and yield formation. This study was undertaken to develop a dynamic module of biomass partitioning over the entire duration of growth in wheat. The partitioning fraction of shoot or root was defined as the fraction of its dry weight in plant biomass, and partitioning fraction of green leaf, stem or ear as the fraction of its dry weight in shoot mass of wheat. The functional relationships of the partitioning fraction with physiological development time for the entire growth period were established, in which harvest index (HI) regulated partitioning fraction of ear to shoot biomass as a genetic parameter. The dry weight of individual organ was the product of the respective partitioning fraction and plant weight or shoot weight. Test of the model with the field experiment data sets involving different sowing dates, plant densities and nitrogen fertilization strategies indicated a good agreement between the predicted and observed values.     

氮素供应对春玉米产量及冠层部分指标的影响与相关分析

采用辽宁地区5个地方品种进行低、中、高3个氮素水平的比较试验(N0:不施氮、N1:112 kg/hm~2、N2:225 kg/hm~2),探究氮素对玉米冠层指标的影响及与产量因素的相关性。相关、逐步回归分析表明,随着施氮量升高,品种产量和穗粒数显著提高。不同氮素水平下,冠层指标与产量因素相关性有差异。穗粒数在N0处理下,与吐丝期叶氮比(SLN)和叶片氮浓度呈负相关,相关强度排序为吐丝期SLN吐丝期叶片氮浓度;N1处理下,与乳熟期LAI呈正相关,与吐丝期叶片氮浓度和吐丝期绿叶数呈负相关,相关强度排序为吐丝期叶片氮浓度乳熟期LAI吐丝期绿叶数;N2处理下,穗粒数与冠层指标相关性不显著。百粒重在N0处理下,与吐丝期穗位叶SPAD值呈正相关,与吐丝期LAI和乳熟期穗位叶SPAD值呈负相关,相关强度排序为吐丝期LAI吐丝期SPAD乳熟期SPAD;N1处理下,与乳熟期穗位叶SPAD值呈正相关,与乳熟期LAI呈负相关,相关强度排序为乳熟期LAI乳熟期SPAD值;在N2处理下,与吐丝期比叶面积(SLA)、SLN、乳熟期绿叶数呈负相关,相关强度排序为吐丝期SLN、SLA乳熟期绿叶数。     

Growth rate, senescence and photosynthesis of ryegrass swards cut to maintain a range of values for leaf area index

An experiment was carried out in which simulated swards of ryegrass (cv. S23) were grown in boxes. In the first instance the swards were cut at weekly intervals to maintain five levels of leaf area index (LAI) from LAI 1 to 4–5 in simulation of continuous grazing. Measurements were made of growth, senescence and net growth rate and of net canopy photosynthesis at constant irradiance. The results showed that the swards adapted to the defoliation regimes mainly by changes in tiller population density and pseudostem length. When the swards had equilibrated to the cutting regime growth rate increased with LAI but, since tiller density and the partitioning of growth between herbage harvested and that lost by sensecence also changed with LAI, net growth rate was constant over the LAI range 2–4·5. Maximum weight of herbage harvested was obtained between LAI 2 and 3.
After 10 weeks of weekly cutting all the swards were cut back to LAI 1 and allowed to regrow. Growth rate showed almost no response to the previous culling treatments. The relationship of net canopy photosynthesis to LAI was linear for the frequently defoliated swards and curvilinear for regrowing swards. The reasons for this difference were examined.     

不同施氮量玉米超高产群体特征研究

在采用高产品种密植、深耕、精细播种、灌溉等高产栽培管理措施的条件下,研究不同施氮量对与高产形成有密切关系的群体特征进行了分析。结果表明,随施氮量增加,玉米单产逐渐增加,施氮量为450kg/hm²时单产高达13980.84kg/hm²;生物学产量、收获指数、叶面积指数、群体粒数、粒叶比等反映群体特征的大部分指标随施氮量增加均有不同程度的增加,少数指标如百粒重的变化则不明显。综合分析得出:与收获指数相比,生物学产量对子粒产量的贡献大,玉米营养体建成期间的干物质积累是超高产形成的基础,而灌浆期间的干物质积累则是超高产形成的关键;对产量与其构成因素的通径分析表明,群体粒数是产量的主要贡献因子,百粒重对产量的直接效应不大;玉米超高产群体具有较高的最大叶面积指数(LAI),且其群体叶面积变化动态比较平稳;群体源与库通过增施氮肥均增加的同时,反映源与库在量上相对关系的粒叶比也得到增加。     

Minimizing errors in LAI estimates from laser-probe inclined-point quadrats

Leaf area index (LAI) measurement by the method of inclined point quadrats has recently been automated using laser-induced chlorophyll fluorescence to detect green leaves. The simplest implementation of this approach assumes (i) leaves are randomly distributed, both in azimuth and in horizontal position. and (ii) the laser beam is infinitely thin. These assumptions are violated by heliotropic plants, crops grown in rows, and real-world lasers. Mathematical modeling was used to analyze the resulting errors and to evaluate possible solutions. One model treated crop rows as rectangular prisms filled with leaves categorized by inclination and azimuth angle. Nonrandom leaf azimuth and crop arrangement in rows were predicted to decrease the accuracy of laser-probe LAI estimates. It was also shown that such errors can be reduced to < 15% by averaging LAI estimates from an appropriate range of laser beam azimuths. Sample size was found to be most critical for LAI < 0.5 or > 4. A second model predicted the laser-induced chlorophyll florescence signal (assumed proportional to laser-illuminated leaf area) as a circular laser spot was scanned across a rectangular leaf. Laser beam diameter was predicted to be a significant source of error whenever the radius of the laser beam exceeded the leaf width. This prediction was confirmed experimentally, using rice seedlings growing underwater.     

A model of leaf area development and senescence for winter oilseed rape

In winter crops, leaf area is a major determinant of the final yield, and is substantially affected by losses occurring during vegetative growth. Here, we propose and test a submodel simulating the development of leaf area and pod area, along with leaf senescence, for winter oilseed rape (Brassica napus L.), which was included in a CERES-type model for rape adapted from CERES-N Maize. This crop model, called CERES-Rape, has components for crop phenology, net photosynthesis, N uptake, and assimilate partitioning. As a new feature compared to previously published work, the leaf area submodel includes senescence from shading due to competition for light in the canopy, and from leaf N deficiencies. The model has been developed and parameterised on a 1-yr-long experiment with three fertilizer N treatments in northeastern France, during which measurements of senescing parts allowed calibration of the equations for leaf area index (LAI) senescence and total generated LAI. The leaf area submodel, once coupled to the CERES-Rape model, was tested against two additional experiments from Denmark and northern France. This process-oriented submodel proved accurate for the simulation of actual LAI whether in the calibration or in the validation phase, with an overall Root Mean Square Error (RMSE) of 0.496 m² m⁻², falling close to the mean experimental standard deviation. Extrapolation did not require any further adjustment, although a different cultivar was involved.     

基于库调节的温室番茄干物质生产与分配

研究了库调节对温室番茄（Lycopersicon esculentum Mill．）品种“Capita”干物质生产与分配的影响。结果表明，温室番茄干物质生产主要由LAI决定而与果穗座果数无直接关联，在果穗修剪为恒定的6（或3）个果实时，叶片修剪能显著降低LAI，从而导致植株总干物质生产的显著降低。增加果穗座果数与叶片修剪均能显著提高植株果实的累积干物质分配率。增加植株密度并不能提高植株果实干物质分配率，但可以提高LAI。高密度处理中单位面积植株果实干重的增加主要是由于总的干物质生产增加的缘故。     

Effect of forage removal at the first detectable node stage on the growth of winter and spring triticale

The effect of forage removal on the growth of five winter and five spring triticale genotypes was studied in 1992 and 1993 in field experiments in north-eastern Spain. When cut, winter triticales produced more biomass and leaf area than spring types owing to their higher tillering capacity. The leaf area index (LAI) at anthesis was similar in both groups in both clipped and uncut plots, but spring triticales had a greater leaf area on the main stem than winter types. Winter types had a greater leaf area on the tillers than spring types. Spring and winter types had a similar physiological response to forage removal, except for modifications in flag leaf area. In spring types triticale flag leaf area was reduced by clipping, whereas in winter types flag leaf area was increased. Forage removal resulted in less dry-matter accumulation in all plant parts, maximum weight of the plant being reduced by about 20% and the rate of growth by around 13%. LAI at anthesis decreased by 37% as a result of clipping, and the leaf area duration from anthesis to maturity decreased by 36%. The duration of growth increased after clipping. Heading, anthesis and maturity dates were delayed by clipping, but grain filling duration was not affected.