SPAD-502型叶绿素计在估测大面积区域叶绿素含量中的应用

在每株树木中摘取其上、中、下三部分的叶片,每部分选取5～10片叶子进行测定,对每片叶子的6处不同部位进行SPAD值测定,然后取其平均值作为此片叶子的最终SPAD值,再对所有叶片SPAD值取平均值作为树木的SPAD值。利用GPS技术使树木有了空间信息,并于遥感图像能够结合起来进行分析,为估测大面积区域叶绿素含量创造可能性。结果表明,SPAD-502型手持式测定仪携带方便,测定简单迅速,不损害植被,与GPS技术及遥感反演技术相结合,能简便估测大面积区域叶绿素含量。     

红哺鸡竹叶片叶绿素含量影响因子初步研究

以优良笋用竹种红哺鸡竹为试验材料,采用SPAD叶绿素测定仪测定了不同经营水平和林分密度竹林1～3年生立竹的不同竹冠部位(上部、中部、下部)叶片的叶绿素含量,结果表明:竹林经营水平对不同年龄立竹叶片的叶绿素含量有明显影响,集约经营竹林显著高于粗放经营竹林.在实验林分密度范围内,相同经营水平竹林林分密度对立竹叶片的叶绿素含量无显著影响;高林分密度集约经营竹林竹冠下部的立竹叶片叶绿素含量极显著地高于上部和中部,并以中部最小,低林分密度集约经营竹林随竹冠部位的下降而升高,高林分密度粗放经营竹林随竹冠部位的下降而降低,而低林分密度粗放经营竹林差异不显著.     

基于TM数据估测鞍山市不同林分蓄积量

文章以鞍山市2006年Landsat TM数据和ASTER DEM高程数据为数据源,在提取出波段1~5、7这6个波段后,通过波段运算、缨帽变换、主成分分析等方法获取差值植被指数、土壤调节植被指数、大气阻抗植被指数、垂直植被指数、归一化差值植被指数、比值植被指数等,以及亮度、绿度,前3个主成分等24个变量因子。基于这些变量因子和采样点数据,通过逐步回归模型选择最优模型并估测鞍山市不同林分蓄积量。鞍山市总蓄积量估测模型的相关系数R2是0.73,通过进行交叉验证,发现实测蓄积量和交叉估测值之间的相关系数R2是0.58。基于2007年的森林资源规划设计调查,从森林中提取出针叶林和阔叶林,分不同林分建立蓄积量估测模型;针叶林蓄积量、阔叶林蓄积量估测模型的相关系数R2分别是0.73和0.75。     

杨树叶片SPAD值与叶绿素含量的相关性研究

采用SPAD-502叶绿素仪与分光光度法分别测定了杨树叶片的SPAD值与叶绿素含量,建立SPAD值与叶绿素a、叶绿素b和总叶绿素的线性函数、乘幂函数、指数函数及对数函数的拟合方程,并根据决定系数(R2)确定最佳拟合曲线,以探讨SPAD值与叶绿素含量之间的关系。结果表明:杨树叶片SPAD值与叶绿素a、叶绿素b及总叶绿素含量间均存在极显著正相关关系。SPAD值与叶绿素a含量的最优函数模型为y=0.004 219SPAD1.630 2(R2=0.918 7);SPAD值与叶绿素b含量最优函数模型为y=0.071 308e0.055 468SPAD(R2=0.927 9);SPAD值与叶绿素总量的最优函数模型为y=0.003 24SPAD1.792 1(R2=0.924 3)。通过对9个不同品种叶片SPAD值与叶绿素含量实测值与预测值的统计检验发现,叶绿素a与总叶绿素含量的实测值与预测值间不存在显著差异,可以通过回归方程来预测杨树叶片叶绿素的绝对含量。     

葡萄叶片SPAD值与测定位置及光合色素含量的关系

为了实时、准确、无损地检测葡萄叶片中叶绿素的含量水平,以评价葡萄生长发育与营养状况,确保栽培的科学和施肥的合理,以‘夏黑’‘巨玫瑰’‘户太8号’‘阳光玫瑰’‘金手指’‘摩尔多瓦’这6个品种葡萄叶片为试验材料,采用叶绿素测定仪测定了6个葡萄品种叶片不同位置的SPAD值,使用分光光度计测定了葡萄叶片光合色素含量,探寻了葡萄叶片SPAD值的最适测量位点,分析了SPAD值与光合色素含量的关系,并建立了SPAD值与光合色素含量的线性函数拟合方程。结果表明:6个品种葡萄叶片的SPAD值,叶片顶部的均最高,中部的均次之,基部的均最小;其中,葡萄叶片中部的SPAD值最具有代表性。6个品种葡萄叶片的SPAD值与叶绿素a、叶绿素b、总叶绿素和类胡萝卜素含量均显著相关,其与叶绿素a含量的相关性最高;在不同品种葡萄叶片的SPAD值与叶绿素a、叶绿素总含量、类胡萝卜素含量的线性函数拟合方程中,‘户太8号’的拟合方程决定系数值最高,其叶绿素a、叶绿素总含量、类胡萝卜素含量的决定系数值分别为0.903 5、0.867 2、0.749 9;在叶绿素b与葡萄叶片SPAD值的拟合方程中,‘金手指’的拟合方程为y=0.034 7x-0.084 0,其决定系数R2值(0.773 4)最高。单一品种葡萄叶片的SPAD值与光合色素含量的回归模型的拟合准确率比6个葡萄品种汇总拟合回归模型的要高。     

基于近红外光谱的紫丁香叶片叶绿素含量的估测研究

近红外具有快速无损检测特点,利用该特点能够对紫丁香叶片叶绿素的含量进行估测。采用的试验方法是采取东北林业大学城市示范实验林场中的紫丁香叶片60片,从中随机抽取40片作为建模集,其余20片为验证集,并用偏最小二乘法建立建模集的叶片的近红外光谱和叶绿素含量的关系模型。再利用该模型来估测验证集紫丁香的叶绿素含量。本次试验,建模集的预测集和校验集的R2分别达到0.86和0.73,相关系数均达到85%以上,并且验证集的R2值达到0.82,相关系数为90.85%,说明近红外技术具有应用于叶片叶绿素含量估测的潜力。     

紫丁香叶片面积测量方法的研究

选取５个地点典型紫丁香叶片为材料，用回归相关和乘常数法研究了紫丁香叶片长、宽与叶片面积的关系。结果表明：叶片面积与叶片长、宽的相关系数均达到１％祖显著水平，与叶片长、宽的直线关系（ｙ＝ａ＋ｂｘ）及与叶片长、宽的两种曲线关系（ｙ＝ａｘ￣ｂ、ｙ＝ａ＋ｂｌｏｇｘ）成立；用它们去估测叶片面积，能得到极相似的结果。用乘常数法估测叶面积简便、易行。两种方法的估测值与实测值之间差异均不显著，都具有不需离体、准确、快速及易于推广等优点。     

基于Landsat TM数据的高山松林生物量研究

以香格里拉地区高山松林为对象,对香格里拉地区高山松林生物量进行了研究。生物量模型以香格里拉地区2009年Landsat-5TM遥感图像数据和2011年野外调查获得的45个样地调查数据为基础,利用遥感数据提取各波段灰度值、植被指数和地学数据共14个因子作为自变量,分别运用逐步回归分析方法和主成分分析方法提取的的主成分建立了以样地实测生物量为因变量的生物量估算的回归模型。两个模型经方差分析及相关性检验,均达到显著相关水平,相关系数R分别为0.519和0.581,可用于高山松林生物量的估测,但是估测精度都较低。其中利用主成分分析建立的模型精度高于利用逐步回归分析法建立的生物量模型。     

基于RS的闽江流域马尾松林分蓄积量估测模型研究

从福建省第5次森林资源一类调查落在闽江流域的样地中抽取马尾松林样地130个,以RS可提取因子及样地林分立地条件因子为可选变量,利用3倍标准差法进行异常数据的筛选,对林分立地条件定性因子进行数量化处理,通过逐步回归构建闽江流域马尾松林分蓄积量估测模型,研究结果所构建的蓄积量估测模型的相关系数为0.735。经模外抽取30个样地对估测模型适用性检验和精度验证表明,在可靠性α=0.01条件下模型估测值与外业实测值无显著差异,模型的林分蓄积量估测精度达85.03%,为此,本研究的蓄积量估测模型对森林经营管理具有现实意义。     

利用航空象片估测林分蓄积生长量与生长率初探

利用落叶松林分和白桦林分连年生长量(Z)与林龄(t)的数学模型;以及落叶松林分和白样林分的蓄积生长率估测模型,模型分别为:Z_落=3.8795t~(-0.3775)、Z_白=4.2252t~(-0.3587);P_(M落%)=0.6225/t、P_(M白%)=0.6413/t。只要在航片上能准确的判读小班林龄,就能估测出小班林分蓄积生长量(Z)及生长率(P%)。而林龄(t)与优势木冠幅(G_k)相关极为紧密,有如下关系:t落=9.2692G_k~(1.4039)(R=0.9927)、t白=16.1089G_k~(1.1964)(R=0.9509)。在航片上可量测优势木冠幅(G_k)得林龄(t),再将林龄(t)代入上式各式,即可得林分蓄积生长量(Z)及生长率(P%)。     

3种木兰科植物叶片SPAD值的分布特征及其与叶绿素含量的关系

为探讨3种木兰科植物灰木莲Manglietia glauca、醉香含笑Michelia macclurei和乐昌含笑Michelia chapensis叶片SPAD值的分布特征及其与叶绿素含量之间的关系,采用SPAD叶绿素计和分光光度法分别测定了三者叶片SPAD值和叶绿素含量.结果表明:3种植物叶片SPAD值的差异主要...     

不同经营模式对毛竹叶片特性和竹笋产量的影响

为了研究不同经营模式对毛竹Phyllostachys heterocycla ‘Pubescens’笋用林叶片特征以及竹笋产量的影响,以不同经营模式(带状、层状、加客土和常规经营)的毛竹笋用林为研究对象,对毛竹叶片SPAD值(soil and plant analyzer development value,SPAD value)和叶面积指数(Leaf Aea Index,LAI)进行监测,并于次年春统计春笋产量。结果表明:不同经营模式下的毛竹叶片SPAD值随时间呈现先升高后下降的变化趋势,而LAI变化不明显;机械化带状经营模式中处理D_3(条带宽度1 m,保留条带内立竹和适当竹鞭)的SPAD值及LAI均高于常规经营,且其LAI显著高于(P<0.05)层状和加客土经营中的各处理。层状经营模式中处理C_2(去除竹林地0～25 cm土层的竹鞭)的SPAD值和LAI均较低于同时期的其他处理;机械化经营模式中的处理D_3和处理T_6(加客土6 cm)的春笋产量最高;毛竹SPAD值、LAI及春笋产量三者均呈极显著正相关(P<0.01),其中SPAD值与春笋产量呈极显著正相关(P<0.01)。     

Relationships between reflectance and absorbance chlorophyll indices with RGB (Red,Green, Blue) image components in seedlings of tropical tree species at nursery stage

Methods based on RGB (Red, Green, Blue) image segmentation may emerge as a new and low-cost method for estimation the quality of tree seedlings. However, the vast number of indexes based on the use of the RGB image segmentation and the lack of references in the literature still hinder the widespread use of this technology. Thus, we conducted a study aiming to test the relationships between methods based on absorbance and reflectance, widely used for the estimation of chlorophyll contents and physiological status of trees, and ten indexes based on RGB component analysis. We used leaves of five tropical tree species, belonging to different botanical families. Leaf absorbance was measured using the handheld chlorophyll meter SPAD-502, reflectance was measured using a spectrometer and the RGB indices were obtained from digitalized images of the leaves using a flatbed scanner. Modified linear regression models including all five species were used to relate RGB indices to absorbance and reflectance indices. Data collected from leaves of seedlings of five tropical tree species indicated that digital image processing technology can be a useful and rapid nondestructive method for assessment of physiological status of tree seedlings at nursery stage. Among the RGB indexes tested in this study the R, 2R*(G???B)/(G?+?B) and 2G*(G???B)/(G?+?B) are the most promising for analysis the tropical seedlings physiological status and quality.

     

严重水分失衡状态下四照花蒸腾表面的削减

应用RGB图像分析的方法,研究了日本山口市街区生长的四照花（Comus kousa Buerg.）对2007年夏季干热多风的环境的响应。结果表明,许多四照花叶尖叶缘出现焦枯,清晰的暗棕色防护带显示在焦枯的叶片上。这些防护带逐渐从叶尖向叶基退缩直到成功控制焦枯为止,且留下许多不成功的防卫痕迹。焦枯的叶片呈现鲜明的逻辑斯蒂函数式变化趋势。依据气象数据分析,四照花叶片退缩型焦枯几乎与干燥峰值期同步。这表明在干燥度突然升高期间,极端的水分亏缺诱发了四照花的防卫反应,从而保护其余部分免于进一步的失水。像素分析结果表明,截止到2007年8月底四照花样树通过局部叶片退缩型焦枯减少了40.2%的叶面积。相比之下,鉴于上半年雨量充足,2008年,相同的样树只有13.2%叶面积减少。不管怎样,四照花的确削减了蒸腾表面积,并且表现出一种独特的蒸腾表面减少方式。既不同于落叶也不同于地上部枯死。依据脱水过程的分析,四照花在突然的干热胁迫下叶尖始发的干缩和叶片防卫反应的共同作用被认为是其蒸腾表面削减的关键所在。     

短序润楠春梢叶色及SPAD值变化

短序润楠(Machilus breviflora)是华南地区极具开发潜力的园林树种之一。文章在分析短序润楠生物学特性基础上,对3 a 生短序润楠实生苗春梢嫩叶生长过程的色彩及 SPAD 值变化情况进行了观测研究。结果表明：短序润楠试验样株春梢的叶色在春季呈现不同的变异类型,可分为橙色、红色和紫色3个色系;嫩叶叶色变化过程中出现紫色系、褐色系、橙色系和绿色系;嫩叶生长过程中,SPAD 值逐步增加。     

A theoretical analysis of the influence of heterogeneity in chlorophyll distribution on leaf reflectance

Attempts to determine the vitality of vegetation and to detect vegetation stress from remotely sensed data have focused on chlorophyll concentration, because it influences the reflectance of vegetation and tends to correlate with vegetation health and stress. Pollution, pathogens and pests can cause localized regions of chlorosis and necrosis across a leaf surface, but the extent to which these patches influence the overall reflectance and spectral signature of the leaf and canopy has not been tested. A conifer leaf model (LIBERTY), which simulates the influence of leaf biochemical concentrations of chlorophyll, water, lignin, cellulose and protein on the reflectance of leaves from 400 to 2500 nm, was used to determine the effect of patches of chlorosis on leaf reflectance. A fraction of the leaf f is assumed to be chlorotic with a chlorophyll concentration C(1). The remainder of the leaf has chlorophyll concentration C(2) such that mean leaf chlorophyll concentration, C(mean) = fC(1) + (1 - f)C(2), is constant for a range of f and C(1) values. LIBERTY can be used to estimate the reflectance of a leaf with a particular chlorophyll concentration at a particular wavelength R(lambda,C) (assuming other leaf properties remain constant), thus we can estimate the reflectance of the chlorotic leaf as fR(lambda,C(1))+ (1 - f)R(lambda,C(2)). The model indicated that small areas of chlorosis have a disproportionately large influence on overall leaf reflectance. For example, a leaf with 25% of its area chlorotic can have the same reflectance (400-700 nm) as a homogeneous leaf with 60% less chlorophyll. Thus, determination of chlorophyll concentration from remotely sensed data is prone to underestimation when chlorophyll is nonuniformly distributed. Hence, attempts to model leaf and canopy reflectance using radiative transfer models will need to consider how to incorporate nonuniform chlorophyll distribution.     

Evaluating Beech Tree Phenology in a Deciduous Broadleaf Forest in Northern Iran Using Ground Observation and MODIS Images

We selected 15 beech trees (Fagus orientalis) from the study area in a mountainous region from 520 to 1310 m above sea level. Ground observations of the beech tree growth process from January to December 2004 in 7- to 15-day intervals were performed both visually and by measuring leaf chlorophyll concentration (chlorophyll meter SPAD-502). Results for the regression analysis showed that the leaved period positively correlated with the air temperature (r?=?.894). Anthesis and SPAD measurements have a negative relationship with air temperature and as temperature increases they appear earlier in the year. Anthesis and SPAD measurements had correlation coefficients of r?=??.883 and r?=??.855, respectively. The anthesis and bud bursting and leaf tip appearance have a negative relationship with increasing altitude from sea level and as altitude increases they appear later in the year. To make phenological events in deciduous broadleaf forests recognizable, we used a seasonal 8-day composite Moderate Resolution Imaging Spectroradiometer/Normalized Difference Vegetation Index (MODIS/NDVI). Prior to leaf expansion, NDVI increased from the 109th day of the year or earlier. Existence of the evergreen plants (Ruscus hyrcanus) on the ground and snow-melting exert an influence on inconsistency of phenology monitoring of MODIS/NDVI images. Regression analysis showed that there is a positive relationship between NDVI and SPAD measurements (chlorophyll content) in beech trees.     

利用 SPAD-502对高山杜鹃氮素营养的快速诊断研究

利用SPAD-502型叶绿素计测定了不同氮水平下高山杜鹃不同生长时期、不同叶位的SPAD 值,分析SPAD值与叶绿素含量和叶片总氮含量的关系。结果表明,不同生长期第1轮和第2轮叶片的SPAD值与叶绿素含量均呈显著线性正相关,其中新梢生长期第1轮叶片的SPAD值与叶绿素含量的相关性最强,而叶绿素各参数中对SPAD值影响最大的是叶绿素b的含量。在不同氮水平下, SPAD值及相对叶色差与单位干重的总氮含量具有显著线性正相关关系, SPAD值的变化能够反映60％的单位干重叶氮含量的变化。因此,可以利用SPAD-502型叶绿素计对高山杜鹃进行快速、无损的氮素营养诊断。