气候变化对内蒙古中部草原优势牧草生长季的影响

研究温性典型草原优势牧草生长季与气候因子变化的关系,对于监测草地环境变化及保护利用,评估区域气候变化对优势牧草生长的影响,指导畜牧业生产等具有重要的科学意义和实践价值.基于内蒙古中部草原3个牧业气象试验站1983-2009年克氏针茅和羊草的物候期、气象资料,对返青、黄枯日期、生长季与气温、降水量之间的关系进行了统计分析.结果表明:(1)27a间,该区的年、春季、夏季和秋季平均气温均呈显著升高趋势,春季升温幅度最大,气候倾向率为0.71-0.84℃/10a;各时段降水量变化除春季呈微量增加趋势外,总体呈减少态势.可见,内蒙古中部温性典型草原区暖干化趋势明显.(2)27a间,锡林浩特克氏针茅和羊草返青日期表现为推后趋势,并与4月降水量呈显著正相关;镶黄旗和察右后旗克氏针茅和羊草返青日期呈提前趋势,并与3-5月气温、降水量呈显著负相关,气温每升高1℃、降水量每增加10mm,优势牧草返青日期约提前3.0-5.1d和1.3-2.1d.(3)该区克氏针茅和羊草黄枯日期均呈提前趋势,与8-9月气温均呈显著负相关,降水量为正相关,气温每升高1℃,克氏针茅黄枯日期提前1.7-10.7 d,羊草黄枯日期提前3.5-11.3d,降水量的影响相对较弱.(4)该区克氏针茅生长季延长趋势明显,羊草生长季缩短趋势明显.克氏针茅生长季与4-10月均温正相关系数最大,羊草生长季与水热系数的正相关系数最大.     

气候变化对内蒙古鄂温克旗典型草原植物物候的影响

植物物候作为气候变化敏感的指示指标,已成为全球气候变化研究的焦点。利用内蒙古典型草原区鄂温克牧业气象试验站1959—2017年的气候资料和1983—2017年的植物物候观测资料,采用趋势倾向率和逐步回归等方法,分析了鄂温克旗气候变化特征,代表性牧草大针茅和羊草返青期、开花期、黄枯期及生长季的变化趋势,并通过偏相关分析探讨了气温、降水和日照时数与牧草生育期的关系,建立了主要牧草物候期的气候模型。结果表明:(1)鄂温克旗近60年平均气温呈极显著波动增加趋势,年降水量和年日照时数的变化很小;(2)30多年来,鄂温克旗大针茅和羊草返青期总体呈推迟趋势,倾向率分别为2.2 d/10a和1.4 d/10a;开花期的变化趋势不明显;黄枯期分别以2.8 d/10a和1.5 d/10a的趋势提前;生长季长度呈明显缩短趋势;(3)3月和4月气温是影响研究区牧草返青最主要的气候因子,气温升高返青期提前;前2个月降水量对大针茅开花期的影响较大;气温升高使得黄枯期提前,而降水量增加则使得黄枯期推迟。     

内蒙古草原羊草物候与气象因子的关系

研究温带草原植物物候与气象因子变化的关系,对于提高草原净初级生产量和碳收支估算的精度,掌握放牧的时宜及其区域差异,具有重要的科学意义和实践价值.该文利用内蒙古草原7个牧业气象试验站1983～2002年的羊草物候观测数据,对返青和黄枯日期与气温和降水量的关系进行了统计分析.结果表明:(1)所有站点的年平均气温均呈显著升高的趋势,多数站点的年降水量呈不显著减少的趋势;同时,各站羊草返青期和黄枯期均以显著提前的趋势占优势,多数站点的生长季节(返青到黄枯的期间)呈缩短的趋势.(2)在区域尺度上,羊草返青日期与返青前一个月均温的负相关最为显著,气温每升高1℃,返青期约提前2.4d;在站点尺度上,森林草原区站点的羊草返青期早晚主要受返青前一个月均温(负相关)的影响,典型草原区站点的羊草返青期早晚主要受前一年10月或11月到返青期累积降水量(负相关)的影响,森林草原区最北部额尔古纳右旗的返青期早晚受返青前一个月均温和前一年10月到返青期累积降水量的共同影响.(3)在区域尺度上,羊草黄枯日期与黄枯前一个月均温的负相关最为显著,气温每升高1℃,黄枯期约提前3.7d;在站点尺度上,羊草黄枯期早晚与前期气温以负相关为主,与前期降水量以正相关为主.     

气候变化对内蒙古草原典型植物物候的影响

自然物候期是气候变化最直观的植物信号记录,自然物候变化是气候与自然环境变化的综合指标。基于1983—2009年内蒙古草甸草原、典型草原和荒漠草原区典型植物马兰草、霸王、贝加尔针茅和羊草生长期物候观测资料和同时段的气象观测资料,利用数理统计等方法,分析了不同草原区典型植物物候期与气候要素间的相互关系,结果表明:(1)1983—2009年内蒙古草原区植物物候期总体呈提前趋势,但地域差异明显,典型草原区植物萌芽返青、开花及黄枯期等物候提早趋势最为明显,说明不同草原区植物物候对气候变暖的区域响应不同。(2)内蒙古草原区植物物候期与气候变化密切相关。春季3—5月累积气温与植物萌芽返青期和开花期呈显著负相关,与日照时数为正相关,降水量对其影响不同草原区差异较大。荒漠草原和典型草原区植物黄枯期早晚与黄枯前1—2个月平均气温呈显著负相关,草甸草原区植物黄枯期与前1—2个月的降水量和日照时数有关,与气温关系不显著。(3)随着气候变暖,马兰草生长期缩短,霸王、贝加尔针茅和羊草生长期延长,其中典型草原区主要植物针茅生长季延长趋势最为明显,荒漠草原次之,草甸草原延长最少。     

新疆天山山区禾本科牧草物候区域差异及其驱动力分析

天山山区地形复杂,同种植被因所处地理位置、地形特征的不同,其生育期对气候变化的响应特征差异明显。基于天山山区1990—2015年气象及物候观测数据,利用数理统计及空间插值等方法,分析了典型禾本科牧草物候空间差异及其关键驱动因子,结果表明:(1)26年来,天山山区年平均气温和年平均0 cm地温明显上升,北坡升温幅度大于南坡;年降水量增加,大致为"北坡趋多,南坡趋少";气候总体呈明显暖湿化趋势。(2)天山山区4个牧业气象观测站所共有的优势禾本科牧草物候呈现较明显的差异,春季返青期普遍提前,黄枯期大多为提前,生长季变化差异较大。(3)返青期主要受温度影响,与当月及春季平均气温、平均0 cm地温显著负相关,春季平均温度每升高1℃,返青日期提前1.98—5.77 d,春季平均0 cm地温每升高1℃,返青日期提前1.40—5.08 d;黄枯期主要受前期气温、0 cm地温和降水的综合影响,与前三个月的气温、0 cm地温显著负相关,与降水显著正相关。(4)在热量条件适合时,降水增加,对牧草的生育期是促进作用,相反,若热量条件不足时,降水增加,则会对牧草的发育产生抑制作用。(5)牧草生育期对于海拔高度的敏感性存在明显差异,随海拔高度的增加,物候对气候变化的响应程度更为显著。     

内蒙古主要草原类型植物物候对气候波动的响应

物候是气候变化的指示者,由于不同地区植被类型不同,导致其对气候波动的响应方式不同。利用2004—2013年内蒙古草原区生态监测站群落优势种物候观测资料和同时段的气象资料,分析了不同草原类型区优势种物候期变化及其与气候因子间的相互关系,结果表明:(1)2004—2013年内蒙古草原区各时段气候波动趋势均不显著,返青前以气温降低、降水增加趋势为主;黄枯前草甸草原、典型草原以气温降低、降水增加趋势为主,荒漠草原变化趋势相反。(2)2004—2013年典型草原植物返青期平均提前4.01 d,黄枯推后10.35 d,生长季延长14.36 d;草甸草原返青期提前2.04 d,黄枯期推后12.68 d,生长季延长14.72 d;荒漠草原物候变化趋势最小,返青期平均提前了1.32 d,黄枯期平均推后了9.58 d,生长季延长了10.90 d。(3)内蒙古草原区植物返青期主要受气温波动的影响,草甸草原返青期与前3个月平均气温的负相关最为显著,气温每升高1℃,返青期约提前1.123 d;典型草原、荒漠草原返青期与前2个月平均气温的负相关最为显著气,气温每升高1℃,返青期约提前1.137 d和1.743 d。(4)典型草原区植物黄枯期受前1—2月平均气温和累积降水的共同影响,与夏季平均气温和当月降水量的相关最为显著,夏季气温每升高1℃,黄枯期约提前2.250 d,当月降水每增加1 mm,黄枯期约推后0.119 d。草甸草原、荒漠草原植物黄枯期与各时段降水、气温的相关均不显著,影响黄枯机制比较复杂。     

东北地区植被物候对气候变化的响应

使用1982—2003年GIMMS-NDVI数据和气候数据,借助GIS空间分析和统计分析方法,分析了东北地区不同植被物候期与气候变化的关系。结果表明:22年东北地区年均温度以升高趋势为主,年降水量以减少趋势为主;针叶林、针阔叶混交林、阔叶林、草甸和沼泽植被生长季开始日期提前受春季温度升高影响显著(P<0.05)。春季降水对植被生长季开始日期变化影响较小,仅对针叶林生长季开始日期的推迟有显著的影响(P<0.05)。植被生长季结束日期受温度变化影响较小,仅草原植被生长季结束日期提前受秋季温度降低影响显著(P<0.05)。降水对东北地区植被生长季结束日期的变化影响高于温度。随着秋季降水量的减少,针阔叶混交林、草原和农田植被生长季结束日提前(P<0.05)。草丛生长季结束日期提前受夏季降水减少的影响显著(P<0.05);农田生长季结束日期提前亦受夏季和9月降水量减少的显著影响(P<0.05)。阔叶林和沼泽植被生长季延长受春季温度升高影响显著(P<0.05);灌丛植被生长季缩短受春季降水量减少影响显著(P<0.05);草丛和农田植被生长季延长受夏季降水量增加影响显著(P<0.05)。     

内蒙古克氏针茅草原植物物候及其与气候因子关系

 植物物候作为气候变化敏感的生物圈指示计, 已经成为全球变化研究的热点。利用1985~2002年地面物候观测数据, 构建了内蒙古克氏针茅(Stipa krylovii)草原植物物候的时间序列谱, 并分析了植物物候的时间变异与气候因子之间的相关关系。结果表明: 1) 从1985~2002年内蒙古克氏针茅草原的气候朝着暖干趋势发展, 主要表现在春、夏气温的显著性增加与秋季(9月)降水的显著性减少; 2) 主要植物物候的变化整体呈返青期推后其它物候期提前趋势; 3) 植物生长盛期(7、8月)对气候变化最敏感; 4) 光照和温度是影响内蒙古克氏针茅草原植物物候格局的主要因素, 年内最寒冷的1月月均温和2、3月的光照对春季返青期具有负效应, 而其它物候期与7、8月的光照则呈显著的负相关关系, 6、7月的降水对发育盛期的花序形成、抽穗与开花具有显著的负效应, 8、9月的降水量能显著推后枯黄期的结束, 从而有利于生长季的延长。     

近20年青藏高原东北部禾本科牧草生育期变化特征

利用1988—2010年青藏高原东北部地区5个站点牧草生育期地面观测数据,分析了近20年代表性牧草返青、开花、黄枯期及生长季的变化趋势,并通过偏相关分析探讨了气温和降水对牧草生育期的关系。结果表明,近20年青藏高原东北部牧草生育期北部推迟南部提前的特征明显。南部的三江源区域返青、开花与黄枯期总体呈显著提前趋势,其中曲麻莱羊茅返青期提前的倾向率达到-4 d/10 a,开花期为-13 d/10 a,黄枯期达到-9 d/10 a,且均通过0.01的显著性检验水平。北部环青海湖区域的海北西北针茅生育期则表现出一定的推迟趋势。生长季长度北部地区延长,而南部除甘德(垂穗披碱草)外均呈明显缩短趋势。近20 a黄枯期的变化幅度明显大于返青期,使得生长季长度的变化更多地受黄枯期变化的影响。1月和3月气温是影响研究区牧草返青最主要的气候因子,气温增高返青提前。开花期南北差异明显,北部与同期气温呈明显负相关关系,南部则主要与开花前2—3个月的降水量密切相关,降水增多大部地区开花期提前。此外,降水也是各地牧草黄枯的主要影响因子。     

内蒙古围封草原枯落物累积对大针茅和羊草生长发育的影响

围封草原枯落物累积通过改变水分和热量的再分配影响植物的生长发育。为探究不同植物种群对枯落物累积的适应性,2015—2017年在内蒙古围封典型草原设置了枯落物去除实验,对土壤温度和水分进行了原位监测,也对群落优势物种大针茅(Stipa grandis)和亚优势物种羊草(Leymus chinensis)种群的生长发育过程及种群数量特征进行了测定。结果表明：枯落物累积显著降低生长季表层和深层土壤温度(1.3—4.6℃和1.5—3.2℃),并提高表层和深层土壤水分(1.4%—10.4%和1.0%—5.0%)。枯落物累积对大针茅种群返青时间的延迟(16.9—24.2 d)显著高于羊草种群的(5.2—6.7 d),但对大针茅和羊草种群的营养生长期无显著影响。枯落物累积显著提高大针茅种群的高度但显著降低其盖度和地上生物量,引起大针茅种群的重要值显著降低(0.38→0.22)。枯落物累积显著提高羊草种群的高度、盖度和地上生物量,进而显著提高其重要值(0.16→0.28)。大针茅和羊草种群重要值排序的更替驱动围封草原植物群落演替。本研究从植物种群的角度为阐明围封草原群落结构与功能改变提供新视角,也为科...     

Numerical approaches towards life cycle interpretation five examples

The ISO-standard for LCA distinguishes four phases, of which the last one, the interpretation, is the least elaborated. It can be regarded as containing procedural steps (like a completeness check) as well as numerical steps (like a sensitivity check). This paper provides five examples of techniques that can be used for the numerical steps. These are the contribution analysis, the perturbation analysis, the uncertainty analysis, the comparative analysis, and the discernibility analysis. All five techniques are described at a non-technical level with respect to basic concept, possibilities, tabular and graphical representation, restriction and warnings, and all are illustrated with a simple example.     

影响水稻光合日变化的酶和相关因素的分析

水稻叶片的最大光合速率出现在上午１０：００时,Ｒｕｂｉｓｃｏ初始活力也在此时达到最大,然后逐渐降低,下午１４：００时略上升后又下降．Ｒｕｂｉｓｃｏ初始活力与光合速率之间极显著相关,相关系数为 ０．９４７４．运用相关性分析、回归分析、通径分析,对晴（有时有云）天气水稻叶片的光合速度、光合关键酶及有关因素的日变化进行综合评估,结果发现中午光合下降主要来自气孔限制,同时Ｒｕｂｉｓｃｏ活性也下降;Ｒｕｂｉｓｃｏ活性是影响光合日变化的又一重要生化因子．体内Ｒｕｂｉｓｃｏ活性受Ｒｕｂｉｓｃｏ活化酶的调节．     

Discrimination of higher plant calluses based on embryogenic capacity and taxonomic classification by pyrolysis mass spectrometry

Pyrolysis mass spectrometry (PyMS) is a rapid, simple, high-resolution analytical method based on thermal degradation of complex material in a vacuum, and has been widely applied to the discrimination of closely related microbial strains. Minimally prepared samples of embryogenic and non-embryogenic calluses derived from various higher plants (sweet potato, morning glory, Korean ginseng, Siberian ginseng, and balloon flower) were subjected to PyMS for spectral fingerprinting. A dendrogram based on the unweighted pair group method, with arithmetic mean of pyrolysis mass spectra, divided the calluses into Siberian ginseng embryogenic callus and the others, which were subsequently divided into embryogenic and non-embryogenic callus groups, regardless of plant species from which the calluses were derived. In the non-embryogenic callus group, the dendrogram was in agreement with the known taxonomy of the plants. These results indicate that PyMS analysis could be applied for discriminating plant calluses based on embryogenic capacity and taxonomic classification.     

Intraspecific variation in Licuala glabra Griff. (Palmae) in Peninsular Malaysia– a morphometric analysis

We studied vegetative and reproductive characters of 74 herbarium specimens of Licuala glabra Griff. (Palmae) collected from 22 localities throughout Peninsular Malaysia. To test the null hypothesis that there are no distinct groups within the species, cluster analysis (nearest neighbour), principal coordinates and principal components analyses were performed on the set of 43 qualitative and quantitative characters. The results obtained suggested that: (1) there are three infraspeciflc groups within the species, viz., the two published varieties glabra and selangorensis as well as a possible third novel taxon; (2) there is clustering of individuals corresponding to their geographic localities; (3) clusters generated using only reproductive characters indicate a biogeographic distribution of populations correlated with the mountain ranges in the peninsula.     

Some remarks about the analysis of active control studies

In an active-controlled trial, the experimental treatment can be declared to be non-inferior to the control if the confidence interval for the difference excludes a fixed pre-specified margin. Recently, some articles have discussed an alternative method where the data from the current study and placebo-controlled studies for the active control are combined together into a single test statistic to test whether a fixed fraction of the effect of the active control is preserved. It has been shown that, conditional on nuisance parameters from the active-controlled study, a fixed margin can be defined that will be operationally equivalent to this latter method. In this article, we will discuss statistical properties associated with these approaches. Specifically, the interim monitoring boundaries and level of evidence will be considered.     

Fish ecoregions of Kansas: stream fish assemblage patterns and associated environmental correlates

Synopsis Principal components analysis was performed on fish presence/absence data for 39 common fish species from 410 stream sites in Kansas. The analysis confirmed ten ecologically meaningful fish assemblages, based on species associations. Factor scores based on these assemblages were then clustered into six geographic areas or fish ecoregions. Canonical discriminant analysis identified environmental variables that distinguished the derived fish ecoregions. Mean annual runoff, mean annual growing season, and discharge appear most important. Mean width, mean depth, chloride concentration, water temperature, substrate type, gradient, and percent of pool habitat were less important. Correspondence exists between these fish ecoregions and the patterns of physiographic regions, river basins, geology, soil, and potential natural vegetation in Kansas. The multivariate statistical approach used to classify fish ecoregions should have considerable potential value for fish assessment and management purposes in areas other than the state of Kansas.     

Normal Approximations of Exact Tests in Configural Frequency Analysis

The most common tests for types and antitypes in configural frequency analysis are normal approximations of exact tests. In the paper such statistics under the complete independence model and under the fixed margins model are discussed. It turns out that these test statistics are not acceptable when the number of simultaneously performed tests is large or when the expected frequencies are small. In these cases, the use of exact tests is advocated and some existing computer programs for such tests are indicated. A normal approximation based on the strong version of the De Moivre-Laplace limit theorem is also discussed. Empirical examples are given from longitudinal data describing psychological development of boys.     

Phenotypic evaluation of genetic variability and selection of yield contributing traits in chickpea recombinant inbred line population under high temperature stress

Heat is a major abiotic stress that drastically reduces chickpea yield. This study aimed to identify heat-responsive traits to sustain crop productivity by screening a recombinant inbred line (RILs) population at two locations in India (Ludhiana and Faridkot). The RIL population was derived from an inter-specific cross between heat-tolerant genotype GPF 2 (C. arietinum L.) and heat sensitive accession ILWC 292 (C. reticulatum). The pooled analysis of variance showed highly significant differences for all the traits in RILs and most of the traits were significantly affected by heat stress at both locations. High values of genotypic coefficient of variation (19.52–38.53%), phenotypic coefficient of variation (20.29–39.85%), heritability (92.50–93.90%), and genetic advance as a percentage of mean (38.68–76.74%) have been observed for plant height, number of pods per plant, biomass, yield, and hundred seed weight across the heat stress environments. Association studies and principal component analysis showed a significant positive correlation of plant height, number of pods per plant, biomass, hundred seed weight, harvest index, relative leaf water content, and pollen viability with yield under both timely-sown and late-sown conditions. Path analysis revealed that biomass followed by harvest index was the major contributor to yield among the environments. Both step-wise and multiple regression analyses concluded that number of pods per plant, biomass and harvest index consistently showed high level of contribution to the total variation in yield under both timely-sown and late-sown conditions. Thus, the holistic approach of these analyses illustrated that the promising traits provide a framework for developing heat-tolerant cultivars in chickpea.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-00977-5.     

分子水平的遗传多样性及其测量方法

遗传多样性水平是一项很重要的数据。目前从分子水平量化遗传多样性的方法以等位酶分析、ＲＦＬＰ分析和ＲＡＰＤ分析为代表。遗传变异在基因组中并非随机分布,所以取样方式对分析结果的影响不容忽视。本文叙述了遗传变异的产生和分布,并以此为基础比较了上述３种分析方法的理论与实践。     

甲醇对酵母过氧化氢酶活性的影响机理研究

将酵母过氧化氢酶加入一定比例的甲醇,测定其活性变化。结果表明:在含2%甲醇时酶活比对照提高4026%。将粗酶液用70%饱和度的硫酸铵盐析后离心所得的上清液再加入硫酸铵至80%饱和度,离心的沉淀溶解在缓冲液中,上SephadexG75柱,分离出的有酶活性的蛋白峰经电泳得一条蛋白带,说明过氧化氢酶已经被提纯到电泳纯。光谱分析发现,甲醇处理后过氧化氢酶纯酶的吸收光谱和荧光发射光谱与未经处理的比较基本不变,而差示光谱出现明显的正峰和负峰。由动力学分析可知,在甲醇中,过氧化氢酶的Vmax和Km值均有不同程度提高 。