基于上部叶片SPAD值估算小麦氮营养指数

快速、准确的监测诊断小麦氮营养状态对于评价小麦长势、指导氮肥运筹并预测籽粒产量均具有重要的意义.基于2009-2011年的大田试验,系统分析了小麦上部4张单叶不同叶位的SPAD值和归一化SPAD指数(NDSPADij)与氮营养指数的定量关系,通过简单分组线性回归筛选出在不同年际和不同品种间表现稳定的氮营养指数(NNI)定量方程.结果表明,小麦上部不同叶位SPAD值和NNI随施氮量提高而提高,而NDSPADij随施氮量的提高而降低.小麦单叶SPAD值与NNI的关系呈显著正相关,但这种关系在品种或年份之间不稳定,对小麦氮素诊断存在风险;除NDSPAD12外,NDSPADij与NNI之间呈显著负相关,经简单分组线性分析发现NDSPAD14与NNI之间在年份和品种之间表现最稳定,能够较好的定量估算氮营养指数,从而快速诊断小麦氮素是否亏缺.     

木棉叶片叶绿素荧光参数和SPAD值对干旱胁迫的响应

采用盆栽控水干旱法模拟干旱逆境,对1年生木棉(Bombax ceiba)盆栽苗进行不同程度的胁迫处理,测定干旱胁迫时其叶片叶绿素SPAD值和荧光参数动态变化。结果表明,干旱胁迫下,木棉叶片叶绿素相对含量逐渐降低;初始荧光(Fo)随着干旱程度的加剧而呈上升趋势,而最大荧光(Fm)、潜在光化学效率(Fv /Fo)、最大光化学效率(Fv /Fm)、光化学淬灭系数(qP)和表观光合电子传递速率(ETR)下降,在中度和重度干旱胁迫时差异显著(P＜0.05);非光化学淬灭系数(NPQ)变化不显著。干旱胁迫导致木棉植株出现光抑制,植株可通过降低光化学淬灭、增加热耗散的形式增强对干旱的适应能力。     

广义岭回归在家禽育种值估计中的应用

讨论了岭回归方法应用于混合线性模型方程组中估计家禽育种值的方法,其实质是将传统的混合线性模型方程组理解为一种广义岭回归估计,为确定遗传参数的估计提供了一种途径;同时,以番鸭为例,考虑了一个性状和两个固定效应,采用广义岭回归法对公番鸭育种值进行了估计,并与最佳线性无偏预测法(BLUP 法)进行了比较,结果表明,广义岭回归方法和BLUP 法估计的育种值及其排序非常接近,其相关系数和秩相关系数分别达到了0.998~(**)和0.986~(**),且采用广义岭回归法预测的误差率低(在±10%以内);表明在混合线性模型方程组中使用广义岭回归估计动物育种值的方法具有可行性,并可省去估计遗传参数的过程,使BLUP 法在动物选育中的应用更具实用性.     

辽西北主要绿化树种叶绿素含量分异特征及与SPAD值关系

采用分光光度计和便携式叶绿素计测定辽西北主要绿化树种叶绿素含量与SPAD值,并对二者进行相关性分析。结果表明,辽西北主要绿化树种叶片叶绿素a/b为2.35~3.83,当欧氏距离为10时,可将树种划分为3类,即低叶绿素a/b(平均值为2.50)树种6个,中等叶绿素a/b(平均值为2.97)树种29个,和高叶绿素a/b(平均值为3.52)树种20个,3者差异显著(P0.05)。低叶绿素a/b往往反映出植物更能利用弱光,上述结果能够一定程度上反映辽西北各树种耐阴程度的高低。各树种单位鲜重和单位面积叶绿素含量及SPAD值变化范围分别为0.73~4.61 mg·g-1、0.21~0.99 g·m-2和29.42~75.51;变异系数分别为43.6%、35.2%和23.0%。SPAD值与单位鲜重叶绿素b和总叶绿素含量均无显著相关关系(P0.05),而与单位面积叶绿素a、叶绿素b和总叶绿素含量均呈极显著正相关(P0.001),并且与叶绿素a的相关性(R=0.67)高于总叶绿素(R=0.61),高于叶绿素b(R=0.56)。辽西北主要绿化树种叶绿素含量较低,SPAD值可以反映种间单位面积叶绿素含量差异,而不能反映单位鲜重叶绿素含量,根据各树种的耐阴性可以进行合理的树种选择与配置。     

流溪河森林公园六种常见阔叶树SPAD 值的变化与种间差异

为探讨亚热带树木叶片叶绿素SPAD 值的分布规律, 以流溪河森林公园常绿阔叶林的鸭脚木(Scheffleraoctophylla)、罗浮锥(Castanopsis faberi)、黄樟(Cinnamomum porrectum)、猴耳环(Pithecellobium clypearia)、中华杜英(Elaeocarpus chinensis)和黧蒴(Castanopsis fissa)6 种植物为研究对象, 分析植物种间SPAD 值的差异, 不同方向叶片SPAD 值的差异以及SPAD 在叶片各部位的分布。结果表明: 植物种间SPAD 值存在显著差异, 物种与叶片方向和叶片部位对SPAD 值存在显著的交互作用。各树种叶绿素SPAD 值普遍以西边的叶片较低, 体现出与北半球西南朝向受到太阳辐射时间更长这一现象呈负关联。叶绿素SPAD 值在叶片不同部位的分布则表现为: 叶基的SPAD 值最大, 其次为叶中部, 叶尖SPAD 值最小, 中华杜英和黧蒴叶基和叶中部的SPAD 值无显著差异, 叶基和叶尖则差异显著; 其余4种植物SPAD 值在叶片各部位的分布则差异不显著。通过监测该森林公园主要树种的叶绿素SPAD 值, 可以及时获取其光合作用效能和营养状况等信息, 了解其生态系统的生态功能。将SPAD-502 叶绿素计测定叶片叶绿素含量的方法应用于阔叶树的研究中, 以期为野外测定树木叶片叶绿素含量提供参考, 为完善SPAD-502 叶绿素计在林业方面的的应用提供科学依据。     

低N胁迫下巴西橡胶实生苗叶片SPAD值、N素营养及农艺性状的变化

对3个品种(GT1、RRIM600、PR107)巴西橡胶(Hevea brasiliensis)实生苗进行不同N素(0%N,50%N,100%N)处理,分析比较叶片SPAD值、N素营养和农艺性状的变化及其关系。结果表明:(1)缺N胁迫明显降低了叶片SPAD值、叶片N含量和硝酸还原酶活性,缩小了叶蓬距、叶面积,且影响幅度随胁迫强度的加大而增大;(2)不同品种橡胶树实生苗对缺N胁迫的响应程度不同,总体上GT1较为敏感,PR107次之,RRIM600较不敏感;(3)橡胶树实生苗叶片SPAD值、叶蓬距、叶面积与叶片N含量、硝酸还原酶活性之间均呈显著或极显著正相关。因此,有可能采用测定叶片SPAD值、叶蓬距和叶面积等简易方法判断橡胶树新生叶蓬的N素营养状况。     

基于叶绿素荧光参数的小麦叶片叶绿素相对含量估算方法

叶绿素含量是植物学和农业相关研究领域常用的生理指标.叶绿素含量和叶片光合功能密切相关,但是现有的叶绿素含量的测定方法无法实现叶绿素含量和光合功能的同步测定和关联分析.为解决该问题,本研究通过测定35个小麦品种旗叶的SPAD值和叶绿素荧光诱导动力学曲线,分别使用不同时间的快速叶绿素荧光动力学曲线的荧光值,以及33个常用荧...     

深圳福田两种红树林植物叶片分解研究

利用分解袋法研究两种红树林植物(秋茄、桐花)叶片在野外实地分解过程中的干物质和有机C、N、P变化情况.结果表明,秋茄叶片野外分解的速度要比桐花叶片快得多,初始非灰分物质干重(AFDW)损失一半所需的时间秋茄为12d,桐花35d左右.分解开始后,两种叶片的N含量均迅速上升,到达峰值后逐渐下降;而P含量则先略为下降,之后慢慢回升;叶片有机C含量则始终保持在相对较为稳定的水平上.试验的结果还表明,桐花叶片在红树林系统内沿潮汐梯度的不同滩面位置上分解时,各地点的分解速率间无显著差异.     

几种测定植物叶绿素含量的方法比较

植物叶绿素含量的测定大致可分为分光光度计法和活体叶绿素仪法两大类,目前还有人在研究反射型的活体叶绿素仪。本文就这些测定方法作些简要介绍和比较,以供读者参考。 1.分光光度计法由于所用提取叶绿素的溶剂不同,分光光度计法又有多种测定方法。 (1)丙酮法丙酮法是Mackinney(1941)首先     

茶蚜对不同SPAD值绿色的趋性

以茶蚜(Toxoptera aurantii)为研究对象,研究其对模拟SPAD值(叶色值)绿色和不同施氮量处理茶梢的趋性。结果表明:不同虫态茶蚜对不同SPAD值绿色的趋性存在显著差异,茶树叶片含氮量与其SPAD值之间存在显著的线性关系,茶蚜各虫态对模拟绿色趋性最强的SPAD值的相应含氮量分别为:低龄若蚜在2.83%左右,高龄若蚜在2.83%~3.14%,有翅和无翅成虫在3.14%左右;而各虫态表现出最大趋性的茶树叶片相应含氮量分别为:低龄若蚜在2.64%~3.13%,高龄若蚜在2.68%~2.83%,无翅成虫在2.42%~2.84%,有翅成虫在2.63%~3.13%。表明不同虫态茶蚜对茶树叶片含氮量的需要存在差异,其结果可为茶园合理施肥以及控制蚜虫危害提供依据。     

福建华安竹园一些竹类植物叶的热值研究

在冬季对福建省华安县竹园14属46种（含变种和栽培型）竹类植物叶的热值和灰分含量进行了研究。结果表明：竹类植物叶的灰分含量在8.05%-28.14%之间,平均为15.18%;干重热值在14957.3-19111.4J/g之间,平均为17672.1J/g;去灰分热值在19473.1-24646.2J/g之间,平均为20845.6J/g;竹类植物叶干重热值和灰分含量有显著的线性关系,相关方程为Y＝－169.21X 20241(r=0.7370,df=44）,高灰分含量是竹叶干重热值相对较低的重要原因之一。     

A non-destructive determination of leaf chlorophyll in Vitis vinifera

A portable leaf greenness meter (SPAD-501) has been used to provide a rapid and non-destructive measurement of leaf chlorophyll in Vitis vinifera. Leaf extracted chlorophyll was related linearly to SPAD readings. It is suggested that separate linear equations should be developed for each cultivar so as to maximise the accuracy of estimating leaf chlorophyll content as a function of SPAD readings.     

A rapid method for computing the inverse of the gametic covariance matrix between relatives for a marked Quantitative Trait Locus

The inverse of the gametic covariance matrix between relatives, G^-1, for a marked quantitative trait locus (QTL) is required in best linear unbiased prediction (BLUP) of breeding values if marker data are available on a QTL. A rapid method for computing the inverse of a gametic relationship matrix for a marked QTL without building G itself is presented. The algorithm is particularly useful due to the approach taken in computing inbreeding coefficients by having to compute only few elements of G. Numerical techniques for determining, storing, and computing the required elements of G and the nonzero elements of the inverse are discussed. We show that the subset of G required for computing the inbreeding coefficients and hence the inverse is a tiny proportion of the whole matrix and can be easily stored in computer memory using sparse matrix storage techniques. We also introduce an algorithm to determine the maximum set of nonzero elements that can be found in G^-1 and a strategy to efficiently store and access them. Finally, we demonstrate that the inverse can be efficiently built using the present techniques for very large and inbred populations.     

标记辅助选择改良数量性状的研究进展

本系统地介绍了近年来有关标记辅助选择改良数量性状的研究进展,主要包括标记辅助回交、指数选择与最佳线性无偏预测的理论和应用研究概况。理论与计算机模拟表明标记辅助选择比常规表型选择更有效,但在实际育种中并不理想。同时本还就当前标记辅助选择存在的问题和前景进行了讨论。     

Efficiency of genomic prediction for boar taint reduction in Danish Landrace pigs

Genetic selection against boar taint, which is caused by high skatole and androstenone concentrations in fat, is a more acceptable alternative than is the current practice of castration. Genomic predictors offer an opportunity to overcome the limitations of such selection caused by the phenotype being expressed only in males at slaughter, and this study evaluated different approaches to obtain such predictors. Samples from 1000 pigs were included in a design which was dominated by 421 sib pairs, each pair having one animal with high and one with low skatole concentration (≥0.3 μg/g). All samples were measured for both skatole and androstenone and genotyped using the Illumina SNP60 porcine BeadChip for 62 153 single nucleotide polymorphisms. The accuracy of predicting phenotypes was assessed by cross‐validation using six different genomic evaluation methods: genomic best linear unbiased prediction (GBLUP) and five Bayesian regression methods. In addition, this was compared to the accuracy of predictions using only QTL that showed genome‐wide significance. The range of accuracies obtained by different prediction methods was narrow for androstenone, between 0.29 (Bayes Lasso) and 0.31 (Bayes B), and wider for skatole, between 0.21 (GBLUP) and 0.26 (Bayes SSVS). Relative accuracies, corrected for h², were 0.54–0.56 and 0.75–0.94 for androstenone and skatole respectively. The whole‐genome evaluation methods gave greater accuracy than using only the QTL detected in the data. The results demonstrate that GBLUP for androstenone is the simplest genomic technology to implement and was also close to the most accurate method. More specialised models may be preferable for skatole.     

Identification of gametes and treatment of linear dependencies in the gametic QTL-relationship matrix and its inverse

The estimation of gametic effects via marker-assisted BLUP requires the inverse of the conditional gametic relationship matrix G. Both gametes of each animal can either be identified (distinguished) by markers or by parental origin. By example, it was shown that the conditional gametic relationship matrix is not unique but depends on the mode of gamete identification. The sum of both gametic effects of each animal – and therefore its estimated breeding value – remains however unaffected. A previously known algorithm for setting up the inverse of G was generalized in order to eliminate the dependencies between columns and rows of G. In the presence of dependencies the rank of G also depends on the mode of gamete identification. A unique transformation of estimates of QTL genotypic effects into QTL gametic effects was proven to be impossible. The properties of both modes of gamete identification in the fields of application are discussed.