玉米粗脂肪含量高光谱估算模型初探

通过测定不同品种玉米不同器官（叶片、茎、穗和叶鞘）的室内光谱反射率及其对应的粗脂肪含量,采用相关性分析以及单变量线性拟合分析技术,对粗脂肪含量与原始光谱反射率、光谱反射率一阶微分之间的关系进行了分析。结果表明,采用高光谱反射率对玉米粗脂肪含量进行估算具有可行性。对所构建的方程采用3类指标进行精度检验,认为由1 954 nm处光谱反射率一阶微分所构建的指数模型可对玉米粗脂肪含量较好地预测。     

基于回归分析的玉米冠层叶绿素含量高光谱反演分析

以长期定位氮肥梯度试验地为靶区,采集的42个玉米冠层叶片SPAD值作为训练样本,利用无人机为平台搭载高光谱相机获取玉米冠层高光谱影像,从中提取17个光谱参数,采用相关性分析方法遴选出4个与数学变换(R、lgR、1/1gR、1/R、√R、√1/R)前后SPAD值密切相关的光谱参数,并用来构建一元、多元回归方程作为SPAD...     

高光谱数据与棉花叶绿素含量和叶绿素密度的相关分析

 通过获取棉花不同品种、不同种植密度单叶和冠层关键生育时期的反射光谱,与其相应的单叶叶绿素含量（CHL.C,下同）和冠层叶绿素密度（CH.D,下同）进行多元统计的逐步相关分析。结果表明,棉花冠层CH.D在其反射光谱762 nm波段处的相关系数达最大值（R_CH.D=0.8134^**,n=94）;对于一阶微分光谱,单叶CHL.C和冠层CH.D的敏感波段均发生在750 nm波段处,基于750 nm波段的微分数值,建立了棉花CHL.C和CH.D线性相关模型(R_CHL.C=0.7382^**,RMSE=0.1831,n=66;R_CH.D =0.9027^**,RMSE=0.3078,n=94）,为利用高光谱遥感技术精确提取反映棉花生长状况的叶绿素信息提供了依据。     

高光谱反演植被水分含量研究综述

高光谱反演技术凭借快速、有效和不破坏植被的优势,已成为评估植被水分含量的重要方法。本研究概述了利用高光谱数据反演植被水分含量的研究进展。重点介绍了反演植被水分含量模型所用高光谱参数、指数的选择与变换方法,以及建立植被水分含量模型的几种常用方法,并分析了各种方法的适用条件。最后针对目前的研究进行了展望。     

稻瘟病胁迫下水稻叶片叶绿素含量与光谱特征参数的相关性研究

为实现受稻瘟病侵染水稻叶片叶绿素含量的高光谱反演,以‘陵两优268’为研究对象,测定受稻瘟病侵染的85个水稻叶片样品的叶绿素含量和高光谱反射率,分析受稻瘟病侵染的水稻叶片高光谱反射率与叶绿素含量间的相关关系,使用线性与非线性回归技术建立叶绿素含量反演模型。结果显示:叶绿素含量与原始光谱及一阶导数光谱的敏感波段分别发生在700 nm和752 nm,基于光谱特征参数SDr的回归模型均方根误差为1.27,平均相对误差为10.2%。研究表明受稻瘟病侵染水稻叶片光谱反射率差异明显,基于光谱特征参数SDr的回归模型预测叶绿素含量具有较高的精度。     

基于高光谱的棉花叶片磷含量估测模型

研究不同施磷条件下棉花叶片叶绿素含量的变化规律,旨在建立基于高光谱的叶片磷含量估测模型,实现棉花叶片磷含量快速监测。在盆栽试验条件下,设置不同的磷肥量,测定棉花功能叶叶绿素含量与磷含量,并利用植被指数和叶绿素含量的相关性构建磷含量的光谱变量,从而实现利用高光谱对棉花叶片磷含量的定量监测。结果表明：(1)棉花播种后100天左右,叶片磷含量与叶绿素呈现显著关系(决定系数R²=0.96)。(2)利用多个植被指数(X)和叶绿素含量(I)的相关性构建倒一叶、倒二叶、倒三叶、倒四叶的磷含量光谱变量,其中各叶片相关性最优的模型：倒一叶(L₁)为I₁=2.6131X_RENDVI-0.4275,X_RENDV为红边归一化植被指数,R²=0.71,RMSE=0.2;倒二叶(L₂)为I₅=0.0142X_TVI+0.3274,X_TVI为三角植被指数,R²=0.76,RMSE...     

基于高光谱遥感的玉米叶片SPAD值估算模型研究

灌浆期玉米叶片叶绿素含量对玉米光合作用及产量形成具有重要作用。为通过高光谱特征准确、高效估测玉米叶片叶绿素含量,以SPAD值表征叶绿素相对含量,构建了基于光谱特征参数的传统回归模型、基于全谱和光谱特征参数的PLSR模型和BP神经网络模型,并进行了比较分析。结果表明：基于全谱构建的PLSR模型SPAD值拟合效果最好（R ²=0.910,RMSE=2.071）,而基于光谱特征参数所建立的PLSR模型拟合效果可达到与全谱PLSR模型相近的水平。但后者的实测值与预测值拟合效果（R ²=0.867,RMSE=2.581,RPD=2.628）优于全谱PLSR模型,且建模时间短,模型复杂程度降低。BP神经网络模型相较于两种PLSR模型预测效果略差,但优于传统回归模型。综合来看,基于光谱特征参数建立的PLSR模型估测效果最好。     

秋玉米SPAD值的光谱估算模型研究

研究不同秋玉米品种叶片SPAD值与一阶微分光谱的相关关系,筛选出8个品种的敏感波长和一阶微分光谱参数,建立不同品种SPAD值的一元线性、指数、多项式和基于一阶微分光谱参数的预测模型,计算建模集和验证集的均方根误差RMSE和相对误差RE。结果发现,不同秋玉米品种SPAD值与光谱一阶微分相关系数较高,均在0.8以上;不同秋玉米品种光谱一阶微分的敏感波段位于650~680nm;基于敏感波长建立的SPAD值预测模型均表现出较好效果,多项式模型效果最佳,模型估测精度在不同品种间存在差异;在8个秋玉米品种中,正大999的多项式预测模型表现最佳,其建模集RMSE和RE分别为2.762和3.643%,其验证集RMSEv和REv分别为3.322和4.518%。     

夏播“京早7号”玉米叶片叶绿素含量消长规律的研究

研究表明,玉米植株叶片间的叶绿素含量(a+b,a、b,a/b值)变化有明显的区别.基部第一叶,叶绿素含量高峰出现早,维持时间短,呈单峰曲线变化;其余叶片为双峰曲线或多峰曲线变化.随叶位的升高而出现高峰期推迟,顶住叶稍晚;中上位叶最晚.全株叶片中,以17叶(穗位上1—2叶)含量最高,其次为以穗位叶为中心的中上位叶.全株叶片在不同生育期间叶绿素含量的变化,以子粒灌浆高峰始期为最高,在此以前又在展2—3叶期,雄穗生长锥伸长——裂片期;雄穗小花分化——四分体期,抽雄——雌穗叶丝期,出现4个峰期.与叶片干物质积累输出动态有相应的变化.不同序位叶片叶绿素含量以上位叶>中位叶>下位叶,而a/b值则以下位叶>上位叶>中位叶.     

玉米叶绿素含量测定方法研究

以玉米幼苗绿叶为试材，研究了6种叶绿素提取液的吸收光谱和提取效率及低温冷冻对叶绿素提取的影响，结果表明：6种叶绿素提取液的吸收光谱基本相似，可以沿用Arnon法的计算公式进行叶绿素含量的测定；室温下，浸提法要优于研磨法，混合液浸提叶绿素比单独用丙酮或乙醇浸提要快，其中丙酮乙醇（水）配伍提取速度较快而稳定，是最佳的叶绿素提取方法。叶片冷冻后快速浸提确实能加速叶绿素提取速度，但叶绿素易受光热破坏，故应注意遮光。     

Hyperspectral Estimation Model of Chlorophyll Content in Cotton Canopy Leaves under Drip Irrigation at Different Growth Stages

[Objective] This article is aimed to estimate the chlorophyll content of cotton canopy leaves in drip irrigation fields at different growth stages in northern Xinjiang and establish a model for estimating chlorophyll content in growth time series by using hyperspectral. [Method] Using Xinluzao 45 as the experimental material, the chlorophyll content and the corresponding spectral reflectance of cotton canopy leaves at different nitrogen levels and growing stages were measured, and the relationship between 12 indices and the chlorophyll content was analyzed. The estimation models of the chlorophyll content in cotton canopy leaves under drip irrigation were established. [Result] The correlation coefficient between the chlorophyll content of canopy leaves and Vogelmann red edge index was high in the four growing periods of cotton, and the correlation coefficient was 0.944, 0.907, 0.895, 0.930, respectively. And the spectral reflectivity was the highest at the flowering and boll period. The precision of the model established by the multivariate regression method is higher than that of the single exponential linear model with the determination coefficient more than 0.8 and the root mean square error smaller than that of the single exponential linear model. The model of the budding stage (y＝82.509_x1＋89.937_x2－94.438) has the best precision. [Conclusion] The chlorophyll content can be estimated by the models established at different growth stages, and the budding stage model has the best monitoring effect.     

利用高光谱参数预测水稻叶片叶绿素和籽粒蛋白质含量

通过温室水培试验,测定2个品种、4个供氮水平的水稻剑叶在抽穗期后不同生育期的高光谱反射率,及对应叶片的叶绿素、全氮以及籽粒蛋白等生化组分的含量。结合水稻光谱曲线特征以及氮素营养胁迫特点,利用统计相关分析法,研究了9个植被指数和8个微分参数与叶片叶绿素、全氮含量的相关性,结果表明这些相关性均达到正显著水平     

基于近红外波段玉米叶绿素含量最佳预测模型研究

为了进一步探究近红外波段玉米光谱反射率与其叶绿素含量之间的关系,笔者采用线性和非线性法对玉米叶绿素含量与近红外波段光谱反射率及植被指数之间的关系进行分析,建立叶绿素含量最佳预测模型。结果表明：在近红外波段,光谱反射率与玉米叶绿素含量的相关性较大;叶绿素含量与RVI(R1001/R760)、RSI(R765/R720)、NDVI(R990-R760)/(R760+R990)、NDSI(R813-R763)/(R813+R763)、CCI(D794/D763)等植被指数均达极显著相关,其中与NDVI的相关性最大,为0.91。基于近红外波段的植被指数建立玉米叶绿素含量预测模型中,采用RVI、RSI、NDVI、NDSI所建的二次多项式模型其决定系数R2均高达0.75以上。采用990、760nm处的归一化植被指数NDVI建立的二次多项式为玉米叶绿素含量最佳预测模型,其具有最大决定系数(R2=0.855),较小RMSE(2.433)和RE%(0.61%),为利用高光谱信息反映玉米生长状况的叶绿素信息提供了基础。     

Hyperspectral Models for Estimating SPAD Value of Cotton Leaves under Waterlogging Stress

[Object] To setup the hyperspectral sensing models for estimating SPAD value of cotton leaves under waterlogging stress. [Method] Irrigation and drainage controllable plots were introduced to simulate the waterlogging stress treatment in the flowering and boll forming stage, during which the change characteristics of the cotton leaf spectral reflectance and SPAD value were observed after 1 d, 3 d, 6 d, 9 d waterlogging, respectively. To find out the hyperspectral sensing models for estimating SPAD value of cotton leaves under waterlogging stress, the correlation and regression relationships between SPAD value and spectrum parameters were analyzed. [Result] (1) The SPAD value of the fourth cotton leaf from the top was significantly lower than control when suffers from waterlogging for 3 d, when waterlogged 9 d the SPAD value decreased by around 15% compared with the control. (2) The cotton suffering from waterlogged damage in the flowering and boll forming stage caused the reflection peak in green light wave band became steep, while the near infrared spectral reflectance increased, and caused the reduction of red absorption and red edge position blue shifts, the red edge position drifts towards short wave with 4～5 nm when suffers from waterlogging for 9 d. With increase of the waterlogged days, the red edge slope and red edge area increased with a maximum value at 6 d of waterlogging, meanwhile, the skewness and kurtosis of red edge increased. (3) After waterlogging, the SPAD value of the fourth cotton leaf from the top (chlorophyll content) had a remarkable correlation with red edge slope(Dr), red edge position(λr), green peak reflection(Rg), green peak position(λg), red well position(λo), blue edge area(SDb), yellow edge skewness(Sy), yellow edge kurtosis(Ky), red edge skewness(Sr), red edge kurtosis(Kr), etc. An experience linear, polynomial and exponential models for estimating SPAD value had been built through using the Sy, Sr, Kr as independent variables, respectively, their determination coefficient (R²) were greater than 0.9, and the root mean square error (RMSE) were less than 1; and an experience binary linear regression equation for estimating SPAD value had been built through multivariate regression using the λg, SDr/SDb(VI3), Sb, Sy, Ky as independent variables, the R² was as high as 0.973, and the RMSE was 0.393. [Conclusion] The model can be remote sensing model used as estimating leaf SPAD of cotton value under waterlogging stress.     

玉米叶绿素含量基因效应分析

为了研究控制玉米叶绿素含量的遗传规律,以叶绿素含量存在显著差异的2个普通玉米自交系组配的P₁、P₂、F₁、BC₁、BC₂、F₂ 6个世代为试验材料,运用主基因+多基因遗传模型分析方法,探明玉米叶绿素含量的遗传模型,并进行遗传参数估计。结果表明,F₁叶绿素含量杂种优势表现为正向离中亲优势,无超亲优势;玉米叶绿素含量的遗传受2对加性-显性-上位性主基因+加性-显性多基因共同控制,以主基因遗传为主,非加性效应大于加性效应;2对主基因与多基因的加性效应均为减效,显性效应均为增效,上位性效应累计为正向;BC₁、BC₂、F₂叶绿素含量主基因的遗传率分别为74.58%、78.62%、20.84%,多基因的遗传率分别2.84%、7.69%、68.11%。     

DCPTA对低温胁迫下玉米幼苗叶片叶绿素含量及其荧光特性的影响

以郑单958为盆栽试验材料,设置3个昼夜温度梯度(18℃/9℃、16℃/7℃、14℃/5℃),研究喷施不同浓度DCPTA对玉米幼苗叶片的叶绿素含量以及叶绿素荧光特性的调控机制。结果表明,低温胁迫下喷施DCPTA玉米幼苗的叶绿素含量比对照(清水处理)高23.62%~144.55%;玉米叶片Fo(初始荧光)比对照低4.55%~39.53%,Fv/Fo(PSⅡ潜在活性)、Fv/Fm(PSⅡ最大光化学效率)、qN(非光化学猝灭系数)分别比对照高出30.26%~112.39%、7.47%~32.96%、5.98%~57.52%;浓度为50mg/L的DCPTA喷施玉米幼苗叶片后,对低温胁迫下玉米叶片光合系统的保护效果最好,这有利于提高玉米幼苗叶片的抗冷性。     

金光杏梅叶绿素含量变化规律研究

为研究杏梅叶绿素含量变化规律,以金光杏梅为试材,采用直接浸提法,对杏梅不同时期以及不同枝条叶绿素含量进行了测定。结果表明,不同时期杏梅叶片叶绿素a+b含量呈高低起伏波动变化趋势,峰值分别出现在5月中旬、7月中旬和9月上旬;有果短枝、无果短枝叶片叶绿素a+b含量表现出3个高峰和2个低谷,而营养枝叶片叶绿素a+b含量表现出2个高峰;不同时期叶片和不同枝条叶片叶绿素a/b值变化基本均呈"V"字形,在7月中旬出现谷值。次研究可为生产上确定合理灌溉和施肥时期提供参考。     

日光温室甜樱桃叶片叶绿素含量影响因子初探

为探索日光温室甜樱桃叶片叶绿素含量的影响因子,试验测定不同温室方位、不同树体方向、不同树形、不同品种以及叶面肥处理下甜樱桃叶片叶绿素a、叶绿素b和总叶绿素含量。结果表明,温室东部甜樱桃叶片叶绿素含量显著低于温室西部和中部;树体南向和东向叶绿素含量显著大于树体西向和北向;甜樱桃品种间叶绿素a、叶绿素b和总叶绿素含量不同,且差异性不同;施用叶面肥可显著提高温室甜樱桃叶片叶绿素含量;试验中3种树形之间甜樱桃叶片叶绿素含量差异不显著。