水稻多元有害生物为害特征及产量损失量化

收集了云南粳稻主产区沾益、寻甸两县106块稻田水稻有害生物为害和产量等信息,并用两种方法对其分析。第一种方法应用聚类分析和对应分析描述水稻有害生物为害类型和产量水平之间的关系,第二种方法应用主成分分析和多元逐步回归估计各为害的产量损失。聚类分析确定了7种有害生物为害类型,其中IN1、IN2和IN3为害水平较低,而IN5、IN6和IN7为害水平较高。有害生物为害类型和水稻产量水平之间的对应分析,在前两个轴构成的因子空间内绘出了各为害类型和产量水平的位置,并给出了一条与为害类型紧密联系的产量水平增加路线。该分析暗示与位于该因子平面右边的有害生物为害类型(IN1、IN2和IN3)相比,位于左边的为害类型(IN5、IN6和IN7)将引起水稻更大的产量损失。主成分多元回归分析评估了水稻各种病、虫、草害所造成的减产量及其相对重要性。分析结果表明,高于水稻冠层杂草、蛀茎害虫(白穗)、稻纵卷叶螟、白叶枯病、粘虫、叶瘟病和稻飞虱是该稻作区对水稻产量影响较大的为害因子。     

气候变化对黑龙江省水稻障碍型冷害的影响

明确气候变化对黑龙江省水稻孕穗期和抽穗期障碍型冷害的影响,可为水稻安全生产提供科学依据。基于黑龙江省70个台站1971—2012年的气象资料和10个台站1980—2011年水稻生育期数据,结合水稻障碍型冷害指标,分析了气候变化对黑龙江省水稻障碍型冷害的影响。结果表明:(1)水稻孕穗期障碍型冷害1990s发生频率最低,2000s发生频率最高;抽穗期障碍型冷害1970s和1980s发生频率高,1990s和2000s发生频率低。(2)抽穗期障碍型冷害发生程度大于孕穗期障碍型冷害。(3)不同熟型水稻品种可种植北界逐渐北移东扩,极早熟、早熟和中熟品种可种植范围分别缩小了5、21和11个县(市),中晚熟和晚熟品种可种植范围分别扩大了14和23个县(市)。(4)随着水稻种植格局的变化,不同熟型水稻障碍型冷害均在1990s发生频率最低,2000s发生频率最高。     

稻麦两熟系统适期晚播对周年产量和资源利用效率的影响

受气候变化影响,江淮地区稻麦两熟种植模式周年资源配置不合理、资源利用效率低,限制了该区域作物周年高产高效协同发展。通过播期调整优化两季资源配置是提高资源利用效率,挖掘周年产量潜力的重要途径。本研究于2013—2015年进行大田试验,设置不同稻麦播期组合,对其周年产量和资源配置与利用特征进行了比较。结果表明: 与常规种植模式(T₂)相比,稻麦双季适期晚播模式(T₃)通过播期调整协调了两季间资源配置,将小麦季冗余的温光水资源转移给高贡献率作物水稻,水稻季积温、辐射、降雨资源分别占60.5%、46.5%和56.7%,小麦季分别占36.3%、50.0%和40.9%,两季间比值为1.67、0.94和1.39;水稻产量显著提高,并提高了水稻在周年产量中的占比;小麦产量显著降低,但变幅小于水稻;周年总产量提高了336.3 kg·hm^-2。水稻季温度生产效率、光能生产效率和降雨生产效率分别提高了9.8%、5.6%和8.3%,小麦季资源利用效率无显著差异,T₃模式周年温、光、水生产效率分别提高了4.8%、3.1%和6.0%。稻麦双季早播模式(T₁)或双季过晚模式(T₄)均不利于周年产量形成和资源利用。综上所述,充分挖掘水稻季的光温水资源利用潜力是进一步提升江淮地区稻麦周年产量潜力的关键,研究结果可为区域粮食作物周年种植模式产量潜力的挖掘及种植结构调整提供依据。     

水稻为什么也能“旱作”

水稻旱作是我国水稻生产中一重大的耕作制度的改革.水稻旱作对发展农业经济,改善人民生活,扩大商品粮食生产,都具有重要意义. 1.水稻旱作有哪些好处 (1)水稻旱作能充分利用自然降水,使水稻的种植不再受到人工灌水的限制,从而可大力扩大水稻种植面积,提高稻谷产量. (2)有利于对低洼地、水沙地、河边、山间出水地的改造.这样的地块种植水田缺少灌溉     

太湖地区氮肥减量对水稻产量和氮素流失的影响

为明确太湖地区高产稻田适宜施氮量,以减轻农田化肥过量投入所带来的农业面源污染,本研究在调查农户稻田氮肥施用量的基础上,采用基肥机械深施和秸秆还田,设置不施氮肥(N0)为对照,当地习惯施氮水平360 kg·hm~(-2)(N1)以及在此基础上减少氮肥施用量的10%(N2)、20%(N3)、30%(N4)等5个处理,研究其对水稻产量和农田地表径流养分流失量的影响。结果表明:N2处理水稻产量与N1处理大致相当;N2处理水稻产量高的主要原因是由于其经济系数较高;N2处理较N1处理地表径流总氮流失量减少9.2%;从N1到N4处理,减少氮肥施用量,减少了农田总氮流失率,但N2和N1处理差异不显著;从水稻氮素偏流失率来看,每生产百千克稻谷,N2处理的氮素流失量最少。认为通过基肥机械深施和秸秆还田,在太湖地区习惯施氮水平的基础上减氮10%,在保证水稻产量的同时,减少了农田地表径流总氮流失量和水稻氮素偏流失率,并使稻田氮素流失率保持在较低水平。     

陕南秦巴山区水稻施肥现状评价

为了解陕南秦巴山区水稻施肥现状及农户养分资源投入中存在的问题,提出解决问题的对策,对测土配方施肥项目2006-2009年的11个县2854户调查数据进行了分析和评价.结果表明: 陕南秦巴山区水稻平均产量为7822 kg·hm^-2,中等产量农户所占比例为509%.总氮(N)、磷(P₂O₅)、钾(K₂O)养分投入量分别为169、68、54 kg·hm^-2,其中化肥氮(N)、磷(P₂O₅)、钾(K₂O)养分投入量分别为159、62、45 kg·hm^-2,偏生产力分别为51.52、135.69和158.26 kg·kg^-1.根据养分分级等级,农户化肥氮、磷、钾投入合理比例分别为48.0%、42.4%和7.2%,过量比例分别为22.6%、11.2%和0.6%,不足比例分别为29.4%、46.5%和92.2%.如果化肥养分投入不足的农户将施肥量增加到合理水平,陕南秦巴山区水稻可增产7.70万t.该区域水稻施肥存在的问题主要包括:氮肥和磷肥投入过量和不足并存,钾肥和有机肥投入不足.今后该区域水稻施肥的重点是平衡氮肥和磷肥用量,增加钾肥和有机肥用量,增加追肥尤其是钾肥的施用.     

不同镉污染土壤下水稻镉富集与转运效率

选取适合湖南种植的48个水稻品种(系)在中轻度和重度镉污染土壤上进行盆栽试验,通过分析水稻籽粒产量、各器官富集系数、转运系数及植株净化效率,探明不同镉污染土壤对水稻镉富集、转运及净化效率的影响。结果表明:中轻度和重度镉污染土壤下糙米Cd含量、籽粒产量分别为0.010~0.048 mg·kg~(-1)、96.63~152.55 g·盆~(-1)和0.105~0.476mg·kg~(-1)、101.10~165.12 g·盆~(-1),重度镉污染土壤明显促进糙米镉含量增加,但对籽粒产量影响不大;中轻度和重度镉污染土壤下糙米镉富集效率和产量均不存在显著相关性;依据产量和糙米镉富集效率进行聚类分析,将所有品种在中轻度镉污染土壤下分为低镉低产组、低镉高产组;重度镉污染土壤分为高镉低产组、高镉高产组;两种镉污染土壤水稻各器官镉富集大小顺序均为糙米叶茎秆根系,转运效率则为土-根茎-叶茎-糙米根-茎,土壤镉主要转运至根部并富集于根部;水稻镉富集及转运效率受产量因素影响较小,但受土壤镉浓度影响较大;重度镉污染土壤明显增强水稻各器官镉富集和根-糙米各环节镉转运效率,较中轻度镉污染土壤增幅显著;水稻根部的净化效率远高于地上部分。     

水稻垄作养殖蚯蚓对植株生长特性与产量的影响

为解决水稻平作栽培与蚯蚓无法共存的难题,本研究提出一种水稻垄作栽培养殖蚯蚓的技术模式,并探究了水稻垄作栽培与养殖蚯蚓结合对水稻生长特性及产量的影响,通过设计常规水稻垄作栽培(CK)、水稻垄作放养蚯蚓20 g·m-2(RE1)、40 g·m-2(RE2)和60 g·m-2(RE3)的田间对比试验,研究水稻垄作养殖稻蚯蚓模式下植株地上部生长特性、根系生长特性和产量及产量构成。结果表明:与CK处理相比,RE3、RE2和RE1处理水稻地上部干物质积累量在孕穗期至成熟期增幅分别为10.81%～13.70%、9.14%～12.44%和7.23%～8.82%,叶面积指数增幅分别为8.39%～14.40%、6.33%～10.94%和7.02%～10.34%;水稻垄作养殖蚯蚓模式增加了水稻根系干物质量、根冠比、根数和根体积,降低了齐穗后剑叶叶片丙二醛含量,提高了剑叶SOD和POD活性,维持抽穗后剑叶SPAD值和根系伤流液在较高水平,减缓了剑叶叶片衰老,有效提高了抽穗后植株干物质的积累,为水稻产量稳产及增产奠定基础。研究还发现,水稻垄作养殖蚯蚓模式中,RE2和RE3处理的水稻地下部和地上部生长特性整体均优于RE1处理。     

基于生态效应的水稻籽粒蛋白质含量预测模型研究

在中国、日本、泰国不同生态环境下进行多品种籼型和粳型水稻(Oryza sativa)的区域种植试验,通过分析水稻籽粒蛋白质含量与纬度、海拔、抽穗后温度和太阳辐射等气候生态因子的相互关系,确立了影响水稻籽粒蛋白质积累的主要气候生态因子函数,并使用权重系数来进一步修订各气候生态因子对水稻籽粒蛋白质的作用,构建出基于生态效应(主要气候生态因子函数)的水稻籽粒蛋白质含量预测模型。利用不同年份、不同生态点、不同品种类型的试验资料对所建模型进行了检验,籼稻和粳稻籽粒蛋白质含量的预测误差RMSE平均分别为0.27%和0.24%;籼稻试验点和粳稻试验点的预测误差平均为0.25%和0.22%,表明模型总体上具有较好的预测性和实用性。     

增密减氮对东北水稻产量、氮肥利用效率及温室效应的影响

水稻生产正向资源节约和环境友好的方向转型,常规高产稻作技术亟待创新.本研究以粳稻辽星1号为试材,在2012、2013年研究密度增加、基蘖肥减少、穗肥稳定的"增密减氮"栽培模式对东北水稻产量和氮肥利用效率及温室效应的影响.结果表明:与常规高产栽培模式相比,在基本苗增加33.3%和基蘖肥施氮量减少20.0%的条件下,氮肥农学效率和氮肥偏生产力两年平均分别提高49.6%(P0.05)和20.4%(P0.05),单位面积和单位产量的温室效应两年平均分别下降9.9%和12.7%(P0.05).虽然水稻有效穗数和总生物量下降,但结实率和收获指数提高,所以产量基本稳定甚至提高.增密减氮降低了土壤NH_4~+-N和NO_3~--N浓度,提高了氮素回收效率.表明适度增密减氮可兼顾水稻高产、氮肥高效利用和温室气体减排.     

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．     

凡纳滨对虾各月龄性状的主成分与判别分析

为了研究凡纳滨对虾各性状增长规律和判定最佳生长季节凡纳滨对虾的体格与月龄的关系,选择1～6月龄凡纳滨对虾各1000只,选择全长、体长、第一腹节背高、第三腹节背高、第一腹节背宽、头胸甲长和体重共7个性状,进行主成分与判别分析.结果表明:各月龄凡纳滨对虾性状之间均呈现显著的正相关(P<0.01), 其中以全长与体长的相关性最为明显,1月龄凡纳滨对虾体重与形态性状的相关系数较小.各月龄凡纳滨对虾的主成分有所不同,1～2月龄凡纳滨对虾的第一主成分为长度因子,第二主成分为宽度因子,第三主成分为高度因子;3月龄凡纳滨对虾的第一主成分与1～2月龄凡纳滨对虾一致,但第二主成分为高度因子,第三主成分为体重因子;4～6月龄凡纳滨对虾的第一主成分为体重因子,第二主成分为高度因子,第三主成分为宽度因子.1～3月龄凡纳滨对虾形态性状的增长优先于体重, 4～6月龄凡纳滨对虾体重优先于形态性状的增长.错过最佳生长季节的凡纳滨对虾的与体格大小相符的月龄可通过建立的判别式来判断,总的判别准确率为98.98%,其中2～4月龄凡纳滨对虾的判别准确率为100%.     

Comparison of the Halving of Tablets Prepared with Eccentric and Rotary Tablet Presses

The aim of this study was to compare the densification of powder mixtures on eccentric and rotary tablet presses and to establish relationships with the halving properties of the resulting scored tablets. This is an important problem because the recent guidelines of EU require verification of the equal masses of tablet halves. The models of Walker, Heckel, and Kawakita were used to describe the powder densification on the two machines. The calculated parameters revealed that the shorter compression cycle of rotary machines results in poorer densification and lower tablet hardness at a given compression force. This is manifested in poorer halving properties, which are influenced mainly by the hardness. Better densification improves the halving even at lower tablet hardness. This demonstrates that these parameters can be good predictors of tablet halving properties.     

Dna Ploidy Studies of Benign and Malignant Tumours: Comparison of Flow Cytometry and Image Analysis Techniques Using Two Types of Cytological Specimen

DNA ploidy studies were carried out on Feulgen stained smears and cytocentrifuge preparations from 35 malignant tumours and four benign neoplasms using the CAS image analyser. The smears were prepared from scrapings from fresh tumour tissue whereas the cytocentrifuge preparations were prepared from single nuclear suspensions from paraffin-embedded cell blocks from the same tumour. Histograms obtained by image analysis of the tumour scrapes were compared with those obtained on the cytocentrifuge preparations. Concordant results were obtained in four benign tumours (100%) and 32 malignant tumours (91%). The results obtained by image analysis were also compared with results obtained by flow cytometry of the tumour tissue. Discordant results were obtained for three malignant tumours. Possible reasons for the discrepancy include sampling error, tumour heterogeneity and selective loss of cell populations during processing.     

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.     

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.     

Pluralism and diversity: trends in the use and application of ordination methods 1990‐2007

Question: What are the trends and patterns in the application of ordination techniques in vegetation science since 1990? Location: Worldwide literature analysis. Methods: Evaluation of five major journals of vegetation science; search of all ISI‐listed ecological journals. Data were analysed with ANCOVAs, Spearman rank correlations, GLMs, biodiversity indices and simple graphs. Results: The ISI search retrieved fewer papers that used ordinations than the manual evaluation of five selected journals. Both retrieval methods revealed a clear trend in increasing frequency of ordination applications from 1990 to the present. Canonical Correspondence Analysis was far more frequently detected by the ISI search than any other method. Applications such as Correspondence Analysis/Reciprocal Averaging and Detrended Correspondence Analysis have increasingly been used in studies published in “applied” journals, while Canonical Correspondence Analysis, Redundancy Analysis and Non‐Metric Multidimensional Scaling were more frequently used in journals focusing on more “basic” research. Overall, Detrended Correspondence Analysis was the most commonly applied method within the five major journals, although the number of publications slightly decreased over time. Use of Non‐Metric Multidimensional Scaling has increased over the last 10 years. Conclusion: The availability of suitable software packages has facilitated the application of certain techniques such as Non‐Metric Multidimensional Scaling. However, choices of ordination techniques are currently less driven by the constraints imposed by the software; there is also limited evidence that the choice of methods follows social considerations such as the need to use fashionable methods. Methodological diversity has been maintained or has even increased over time and reflects the researcher's need for diverse analytical tools suitable to address a wide range of questions.     

Chemometric evaluation of the anti-cancer pro-drug podophyllotoxin and potential therapeutic analogues in Juniperus and Podophyllum species

Introduction – Podophyllotoxin, deoxypodophyllotoxin, demethylpodophyllotoxin and podophyllotoxone are four therapeutically potent secondary metabolites. There is a dearth of information on the holistic analysis of their distribution pattern in both phylogenetic and ecological contexts. Objectives – To analyse the continuum of the above metabolites in Juniperus and Podophyllum species collected from natural populations in Himalayan environments and the botanical gardens of Rombergpark and Haltern (Germany) using multi‐component LC‐ESI‐MS/MS, coupled with statistically relevant chemometric assessment. Methodology – We evaluated the individual and holistic metabolite profiles and chemometrically correlated the phytochemical loads between various species (infraspecific), organic and aqueous extracts, and populations of the same species from different locations, different species from same location, different species from different locations and infrageneric populations from same and different locations. Results – Multivariate analysis revealed Juniperus x‐media Pfitzeriana as a suitable alternative to Podophyllum hexandrum for commercial exploitation. A significant positive correlation of podophyllotoxone with both podophyllotoxin and demethylpodophyllotoxin, and a negative correlation of podophyllotoxin with both deoxypodophyllotoxin and demethylpodophyllotoxin (infraspecific among Podophyllum), were observed by Kruskal's multidimensional scaling and corroborated by principal component analysis, indicating probable similarity and/or difference between the biosynthetic pathways, and synergistic and/or antagonistic principles, respectively. Finally, linear discriminant analysis and hierarchical agglomerative cluster analysis revealed considerable infrageneric and infraspecific variability in secondary compound spectra and load of the different populations under study. Conclusion – Such holistic studies of plants and their therapeutic metabolites ought to assist in selecting plants, geographical areas and environmental conditions for bioprospecting and global‐scale phytochemical and phylogenetic diversity studies in the future. Copyright © 2010 John Wiley & Sons, Ltd.