基于生理生态过程的大麦顶端发育和物候期模拟模型

为改进已有的大麦生理发育时间模拟模型(YDmodel),以扬州地区5个品种春播条件下的顶端发育和物候发育观测资料和历史资料为依据,构建了基于生理发育时间的顶端发育和物候期机理模型.模型量化了热效应、光周期、春化效应对发育的影响,引入了7个遗传参数,分别为播种到出苗所需的有效积温、灌浆期发育基点温度、生理春化时间、临界日长、光周期反应起始点、最短苗穗期、最短灌浆期.本模型在YDmodel基础上的改进主要有3点:(1)将每日生理发育时间的增量乘以水肥丰缺因子,改为除以水肥丰缺因子表现水肥对大麦发育的影响,客观体现了大麦在水肥丰缺条件下的发育延迟或提早现象;(2)将三段线性函数改为非线性函数表达春化效应和相对热效应,确立了不同品种相对春化效应和相对热效应的曲线族;(3)将线性函数改为正弦函数表达不同品种光周期效应.经测算,各大麦品种到达单棱期、二棱期、雌雄蕊分化期、药隔形成期、雌蕊柱头二裂分叉期、雌蕊柱头毛状突起期等顶端发育阶段的生理发育时间分别为2.6、5.6、11.3、13.1、15.3、18.2、28.7d,到达出苗期、拔节期、抽穗期、灌浆期和成熟期等主要物候期的生理发育时间为0、13.1、28.7、32.8、51.5d,形成了不同大麦品种在不同气候和栽培条件下统一的衡量发育的定量尺度.     

基于生理生态过程的大麦顶端发育和物候期模拟模型检验

为测试研究I 模型BarleyGrow,采用4个生态区(南京、扬州、武汉、昆明)、10个大麦品种在不同播期下的顶端发育和物候期资料,对BarleyGrow、YDmodel和SUCROS模型进行对比检验和评价.利用遗传-模拟退火算法确定各品种的遗传参数,提高了应用程序求算参数的精度.从模型的整体预测效果来看,BarleyGrow对不同地区、不同播期、不同品种的各顶端发育和物候期预测准确而稳定,均方差RMSE在1.06～7.94d之间,而YDmodel为6.26～13.35d,SUCROS为11.22～20.28d.各参试品种对BarleyGrow中灌浆期基点温度、生理春化时间、临界日长、最短苗穗期4参数反应敏感.经改进的生理发育时间(PDT)模拟模型(BarleyGrow)对中国广大地区不同温光条件下的大麦顶端发育和物候发育均具有较好的预测效果,尤其对药隔期、二裂期、毛状期、抽穗期、灌浆期、成熟期的模拟精度高而稳定,表现出较强的机理性以及较好的预测性.     

城市雨洪SWMM 模型的敏感参数研究综述

伴随城市化的发展, 城市降雨径流水文机制发生改变, 城市内涝频繁发生和水质恶化严重, 最终造成城市水生态环境退化现象日益凸显。由美国EPA 研发的SWMM 模型成为城市降雨径流模拟研究的重要工具, 广泛应用于城市降雨径流产生、输移过程及其管理措施效果等方面的模拟研究, 但其参数的确定是其应用的关键性问题。可见, 对SWMM 模型敏感参数进行识别分类及其敏感性研究, 不仅有利于降低SWMM 模型应用时参数选取的工作量, 还可以提高其模拟结果的准确度。将SWMM 模型的主要敏感参数分为6 类: 汇水区性状参数、透水性地表与不透水性地表相关参数、下渗相关参数、传输模块参数、污染物累积冲刷相关参数和其他参数, 并分析得出敏感参数主要受模型输出变量类型、降雨强度和土地利用类型等因素的影响。在此基础上, 提出了针对SWMM 模型参数敏感性方面今后研究的重点, 以期为SWMM 模型在国内的应用与研究提供参考。     

糯大麦与非糯大麦颖果发育过程的解剖学与组织化学研究

为了明确糯大麦与非糯大麦颖果发育的差异,该研究以糯大麦代表性品种(‘白青稞’、‘甘垦5号’)和非糯大麦代表性品种(‘扬农啤10号’和‘苏裸麦1号’)为材料,采用体视显微镜观察、组织化学染色、树脂半薄切片和光学显微镜观察等方法,比较研究了糯大麦与非糯大麦颖果及其胚乳淀粉体发育的过程。结果显示:(1)糯大麦和非糯大麦颖果的形态变化,以及鲜、干重和含水率等的变化规律基本一致,生长曲线均呈"S"型。(2)两类大麦颖果胚乳和果皮的I2/KI染色结果不同,糯大麦胚乳的I2/KI染色结果为红褐色,其果皮被染为蓝黑色,而非糯大麦胚乳和果皮均被I2/KI染成蓝黑色,表明糯大麦和非糯大麦的颖果果皮里直链淀粉含量都较高,且糯大麦胚乳内以支链淀粉为主,而非糯大麦的胚乳内以直链淀粉为主。(3)糯大麦胚乳淀粉体的出现时间早于非糯大麦,且其中小淀粉体的比例高于非糯大麦,淀粉体充实状况也好于非糯大麦。(4)与非糯大麦相比,糯大麦表观直链淀粉以及总淀粉含量较低,但可溶性糖含量较高。研究表明,糯大麦颖果生长规律与非糯大麦类似,但内含物淀粉的积累规律不同。     

昆虫发育模型研究进展

<正> 昆虫发育模型描述温度对昆虫发育过程的影响。目前,国内外广泛使用的昆虫发育模型归纳起来有3类:(1)发育速率模型;(2)发育时间分布模型;(3)随机发育模型。下面简要介绍各类模型的特点及应用情况。     

大麦胚和胚乳发育的相关性及贮藏营养物质的积累

大麦(Hordeum vulgare L.)开花后1d,见合子及退化助细胞,游离核胚乳尚未形成;开花后2～3d,胚为5及10个细胞,胚乳为游离核期;开花后4及5、6d,胚为梨形及长梨形,胚乳达细胞化期;开花后8d,胚为胚芽鞘期,糊粉层原始细胞产生;开花后10d,胚具1叶,糊粉层1～2层;开花后13d胚为2叶胚,亚糊粉层发生;开花后17d,3叶胚形成,糊粉层多为3层并停止分裂,菱柱形及不规则胚乳细胞分化;开花后21～29d,胚为4叶胚,胚乳进一步分化;开花后33d,胚为5叶成熟胚,胚乳亦成熟。淀粉、蛋白质在胚中积累始于开花后13d。在盾片中由基向顶发生,在胚芽鞘及叶原基中,首先在顶端出现。成熟盾片顶端的淀粉消失。开花后6d,胚乳开始积累淀粉;开花后10d,糊粉层及胚乳细胞积累蛋白质。开花17d后胚乳的蛋白质体多聚集,29d后蛋白质体显著减少。开花后17d,在盾片及糊粉层细胞中检测到油脂。果长或果长与稃片长之比和盾片长可作为不同发育期胚和胚乳的形态指标。     

冷敏感植物的低温光抑制及其生化保护机制

阐述了冷敏感植物光抑制的发光机理、光与低温在光抑制中的关系及冷敏感植物在低温光抑制过程中的生理化变化,并结合冷锻炼对植物的影响,介绍了植物防制光破坏的生化机制。     

水稻感光性和光敏不育性的发育遗传关系

在人工气候室控制的光长与温度下,用光敏不育系7001S与早中熟粳稻(Oryza sativa ssp,japoni-ca)感光性弱的“秋光”、“有芒早粳”和“CPSLO-l7”3个品种分别杂交,分析了杂种F_1、F_2植株育性与感光性的表现,以及两者的关系。结果表明:这3个组合的恢复亲本均属于具两对光敏不育的恢复基因的品种。F_1植株均倾向晚熟亲本,说明控制感光性强的基因属于显性。F_2植株在长日照下表现为不育株的感光性均倾向感光性强的亲本;且有不少不育株为晚熟超亲;在少数弱感光性的植株中没有不育株。说明光敏不育基因与感光性基因关系密切,可能两者有连锁关系,光敏不育基因要在感光性基因表达的基础上才能表达。     

Molecular mapping of the photoperiod response gene ea7 in barley

 The gene ea ₇ determining photoperiod insensitivity under short day length was mapped on the short arm of chromosome 6H near the centromere. The gene was linked to the two flanking markers Xmwg2264 and Xmwg916 by 6.7 and 13.0 cM, respectively. Compared to Ppd-H1 (chromosome 2H) and Ppd-H2 (chromosome 1H), ea ₇ determines the strongest effect on flowering time with 55 and 18 days difference compared to photoperiod sensitive genotypes grown under short and long photoperiods, respectively. Allelic and homoeologous relationships to major genes and quantitative trait loci controlling flowering time in barley and wheat are discussed. Received: 10 March 1998 / Accepted: 7 April 1998     

生态过程模型敏感参数最优取值的时空异质性分析——以BIOME-BGC模型为例

生态过程模型是当前研究陆地生态系统水循环、碳循环有力的工具,但此类模型参数众多,参数的合理取值对模型模拟结果有重要影响.以往研究对模型参数的敏感性以及参数的优化取值有诸多的分析和讨论,但有关参数最优取值的时空异质性关注较少.本文以BIOME-BGC模型为例,在常绿阔叶林、落叶阔叶林、C3草地3种植被类型下,通过构建敏感性判别指数,筛选出模型的敏感参数,并在每种植被类型下选取两个试验站点,使用模拟退火算法结合实测通量数据构建目标函数,获取各站点敏感参数逐月的最优取值,然后构建时间异质性判别指数、空间异质性判别指数和时空异质性判别指数对模型敏感参数最优取值的时空异质性进行定量分析.结果表明:BIOME-BGC模型在3种植被类型下遴选出的敏感参数大部分一致,少数有差异,但参数的敏感性强弱在不同植被类型下的表现不尽相同;BIOME-BGC模型敏感参数的最优取值,大都具有不同程度的时空异质性,但不同植被类型下,敏感参数最优取值的时空异质性表现各异;敏感参数中与植被生理、生态相关的参数,其时空异质性相对较小,而与环境、物候相关的参数,其时空异质性普遍较大;在3种植被类型下,模型敏感参数最优取值的时间异质性与空间异质性表现出显著的线性相关性;依据其最优取值的时空异质性,可对BIOME-BGC模型敏感参数进行类型划分,以便在实践应用中采取不同的参数率定策略.本研究结论有助于加深对生态过程模型参数特性及最优取值的理解,可为实践应用中模型参数的合理取值提供一种思路和参考.     

Morphology and ultrastructure of 11 barley shrunken endosperm mutants

Summary Eleven Na-azide induced barley shrunken endosperm mutants expressing xenia (sex) were characterized genetically and histologically. All mutants have reduced kernel size with kernel weights ranging from 11 to 57% of the wild type. With one exception, the mutant phenotypes are ascribable to single recessive mutant alleles, giving rise to a ratio of 31 of normal and shrunken kernels on heterozygous plants. One mutant (B10), also monofactorially inherited, shows a gene dosage dependent pattern of expression in the endosperm. Among the 8 mutants tested for allelism, no allelic mutant genes were discovered. By means of translocation mapping, the mutant gene of B10 was localized to the short arm of chromosome 7, and that of B9 to the short arm of chromosome 1. Based on microscopy studies, the mutant kernel phenotypes fall into three classes, viz. mutants with both endosperm and embryo affected and with a non-viable embryo, mutants with both endosperm and embryo affected and with a viable embryo giving rise to plants with a clearly mutant phenotype, and finally mutants with only the endosperm affected and with a normal embryo giving rise to plants with normal phenotype. The mutant collection covers mutations in genes participating in all of the developmental phases of the endosperm, i.e. the passage from syncytial to the cellular endosperm, total lack of aleurone cell formation and disturbance in the pattern of aleurone cell formation. In the starchy endosperm, varying degrees of cell differentiation occur, ranging from slight deviations from wild type to complete loss of starchy endosperm traits. In the embryo, blocks in the major developmental phases are represented in the mutant collection, including arrest at the proembryo stage, continued cell divisions but no differentiation, and embryos deviating only slightly from the wild type.     

A novel late embryogenesis abundant protein and peroxidase associated with black point in barley grains

Black point of barley grain is a disorder characterised by a brown-black discolouration at the embryo end of the grain. Black point is undesirable to the malting industry and results in significant economic loss annually. To identify proteins associated with barley black point we utilised a proteomic approach with 2-DE to compare proteins from whole grain samples of black pointed and healthy grain. From this comparison two condition-specific proteins were identified: a novel 75 kDa late embryogenesis abundant (LEA) protein and a barley grain peroxidase 1 (BP1) that were specifically more abundant in healthy grain and black pointed grain, respectively. Although LEA protein was less abundant in black pointed grain, LEA gene expression was greater suggesting protein degradation had possibly occurred in black pointed grain. Similarly, the increase in BP1 in black pointed grain could not be explained by gene expression. Western blot analysis also revealed that the identified LEA protein is biotinylated in vivo. The role that each of these proteins might have in black point development is discussed.     

Development of STS markers closely linked to the Ppd-H1 photoperiod response gene of barley (Hordeum vulgare L.)

A BC₂ population of 353 plants segregating for the Ppd-H1 photoperiod response gene was developed from a cross between the winter barley ’Igri’ and the spring barley ’Triumph.’ Bulk segregant analysis identified six AFLP markers closely linked to the Ppd–H1 gene and three strongly amplified AFLP bands that mapped 0.8-cM distal, 0.6-cM proximal and 2.3-cm proximal to Ppd-H1 were cloned and sequenced. Southern-blot analysis showed that the cloned fragments were single-copy sequences in ’Igri’, the variety from which they were derived. Two of the sequences were absent from ’Triumph’ while the third detected a single-copy sequence. The cloned fragments were used to design specific sequence tagged site (STS) primer pairs to assist in the construction of a high-resolution map of the Ppd-H1 region. Received: 22 March 2000 / Accepted: 10 April 2000     

Sister chromatid exchanges in barley

Summary A mean frequency of 20.6 sister chromatid exchanges (SCEs) per cell has been observed in a reconstructed karyotype of Hordeum vulgare by application of the FPG technique after unifilar incorporation of BrdU into chromosomes. The involvement in SCEs of the 48 segments into which the chromosome set had been subdivided was, with a single deviation, length proportional and independent of the segment's heterochromatin content. Asymmetric bands, indicative of an uneven distribution of adenine and thymidine between the DNA strands in adenine (A)-thymidine (T) rich chromosome regions, could not be detected after incubation of the cells in BrdU for one cycle of DNA replication.     

Cloning and expression of the tubulin genes in barley

Tubulins are encoded by small gene families in plants. Based on the barley EST collection, cDNAs for alpha-, beta-, and gamma-tubulins were selected. Five genes for alpha-tubulin, eight newly identified beta-tubulin sequences and one gamma-tubulin gene were found to be expressed in barley. In silico analysis of relative abundance of the distinct tubulin sequences among ESTs derived from different libraries revealed that the various tubulin genes differed in their level of expression, and to some extent were tissue specific.     

Effect of autopolyploidy on quantity and quality of protein in barley

Summary The range and mean protein content of autotetraploids of high-lysine Notch-2 mutants of barley were consistently higher than the diploids in C₃ and C₄ generations of colchicine treated seeds. Amino acid analysis of whole grain meal of diploid Notch-2 and one strain of its autotetraploid revealed differences in the amino acid composition. The proportion of albumin in the diploid and the autotetraploid Notch-2 was higher by 21% and 45% respectively, in comparison to the parent N.P. 113, whereas the glutelin fraction was significantly higher in the autotetraploid. The autotetraploid, with increased glutelin and decreased prolamin, showed no increase in lysine. It is possible that the recessive high-lysine gene may be lacking dosage effect, resulting in no increase in lysine in the autotetraploid, whereas protein content, a polygenically controlled trait, is enhanced due to genome duplication.