番茄花发育分子生物学研究进展

番茄(Solanum lycopersicum L.)是重要的经济作物,同时也是用于研究多年生合轴植物花发育过程的重要模式植物。植物花发育的过程大致分为4个阶段:开花过渡、分生组织特征决定、花器官发生和花器官形态建成。近年来有关番茄花发育过程的研究已取得了长足进展,但很少有针对此过程的综合描述。本研究通过对近年来国内外关于番茄花发育相关研究针对花发育过程中形态学特征及基因调控进行综述,主要论述了参与番茄开花诱导及分生组织特征决定这两个过程的基因以及基因间相互关系,为对这两个过程进行更深入的研究提供理论依据。     

调控植物花发育的miRNAs的研究进展

花发育是高等植物生长发育过程中的重要事件,可剖分为开花诱导、花的起始和花器官发育3个阶段,是由多种基因参与的十分复杂的调控过程。20年来,人们应用克隆、诱变和突变体等研究技术从模式植物中分离和鉴定了大量调控花发育的功能基因或调控因子,其中,microRNA(miRNA)是本世纪初才发现的一类新的调控因子。miRNA是生物体内长度约为21个核苷酸的非编码小RNA,通过与靶mRNA的互补配对而在转录后水平上对基因的表达进行负调控,导致mRNA的降解或翻译抑制。大量研究证实miRNA在花发育中起着重要的作用。文章重点综述了植物miRNA的作用机制、其功能研究方法及7个miRNA家族在花发育中的生物功能,并对其未来的发展方向进行了展望。     

共培养对土壤重金属污染植物修复的调控作用

A co-culture of two plant materials, Astragalus sinicus L., a leguminous plant with concomitant nodules, and Elsholtzia splendens Naki-a Cu accumulator, along with treatments of a chelating agent (EDTA), root excretions (citric acid), and a control with E. splendens only were used to compare the mobility of heavy metals in chelating agents with a co-culture and to determine the potential for co-culture phytoremediation in heavy metal contaminated soils. The root uptake for Cu, Zn, and Pb in all treatments was significantly greater (P < 0.05) than that of the control treatment. However with translocation in the shoots, only Cu, Zn, and Pb in plants grown with the EDTA treatment and Zn in plants co-cropped with the A. sinicus treatment increased significantly (P < 0.05). In addition, when a co-culture in soils with heavy and moderate contamination was compared, for roots in moderately contaminated soils only Zn concentration was significantly less (P < 0.05) than that of heavily contaminated soils, however, Cu, Zn, and Pb concentrations of shoots were all significantly lower (P < 0.05). Overall, this \"co-culture engineering\" could be as effective as or even more effective than chelating agents, thereby preventing plant metal toxicity and metal leaching in soils as was usually observed in chelate-enhanced phytoremediation.     

三种植被类型植物根系对崇明岛海岸带稳定性的影响

Coastal erosion is currently a major problem along the southern coast of Chongming Island, Shanghai. To enhance the erosion protection ability of coastal shelterbelts, two woody tree species, Taxodium ascendens and Salix babylonica, were planted separately into Phragmites australis + Scirpus mariqueter communities in 2006. Two years later, we investigated whether either of these experiments reduced erosion and increased stability in the native herbaceous plant community. We also examined soil stability and root length density under T. ascendens added, S. babylonica added and native herbaceous vegetation conditions along an intertidal gradient from the soil surface to a depth of 40 cm in each experiment, thus to determine the capacity of T. ascendens and S. babylonica to contribute to shoreline stabilization. Topsoil under the native vegetation had greater stability at the middle and higher intertidal zones because its soil stability index and root length density were significantly higher than in the T. ascendens or S. babylonica planted communities. The effect of T. ascendens on soil stability was not generally better than that of the native vegetation. Only at the 20-30 cm soil depth of the middle intertidal zone and in the 10-20 cm layer of the higher intertidal zone the soil stability index and root length densities under the T. ascendens added condition were significantly higher (P < 0.05) than those of the native vegetation. The S. babylonica planted soil had greater stability in the deeper soil layer than the soil under either the native vegetation or the T. ascendens added condition, and its soil stability index and root length density were significant higher (P < 0.05) than those of other vegetation conditions at the 30-40 cm soil depth for the lower intertidal zone and at the 20-40 cm layer for middle and higher intertidal zones.     

喀斯特区不同岩性发育的土壤上植物-枯落物-土壤系统δ13C值变化特征

为了解喀斯特区不同岩性发育的土壤上林分碳元素循环特征,采用稳定碳同位素技术,研究贵州省喀斯特区白云岩、白云质砂岩、石灰岩3种岩性发育的土壤上猴樟(Cinnamomum bodinieri)、柏木(Cupressus funebris)、马桑(Coriaria nepalensis)、光皮桦(Betula luminifera)、桤木(Alnus cremastogyne)和圆果化香(Platycarya longipes)6种树种为优势种构建的林分的优势种植物-枯落物-土壤系统δ~(13)C值的变化和土壤有机质更新。结果表明:(1)部分树种在不同岩性上的δ~(13)C存在差异,石灰岩上柏木δ~(13)C值与其他岩性呈极显著性差异(P0.001),桤木在石灰岩与白云岩上呈显著性差异(P=0.024);不同树种表现为猴樟、柏木、马桑3个树种相互间或与其他树种多表现出显著性或极显著差异(P0.05或P=0.001);树种各器官δ~(13)C值呈叶片枝杆根的分配格局。(2)3种岩性上,各树种林分变化规律基本一致,均为植物叶片(新鲜枯落物)枯落物分解层枝杆根上层土壤下层土壤。土壤层与植物体、枯落物之间的δ~(13)C值存在极显著差异(P0.001),土壤层与枯落物层比较,增幅较大的是白云质砂岩上的猴樟林和柏木林,分别为11.68‰,11.10‰,增幅较小的是白云岩上的马桑林和石灰岩上的桤木林,分别为1.07‰,2.73‰。(3)土壤有机质更新率最大为白云岩上马桑林43.84%,其次为石灰岩上桤木林34.17%,最低为石灰岩上的圆果化香林1.15%。白云岩上植物群落的有机碳周转率回归方程斜率K值为3.15,石灰岩上为0.85。白云质砂岩上林分的有机碳含量与δ~(13)C值无相关性。研究结果对揭示喀斯特地区C元素循环及迁移特征和养分迁移特征具有重要意义。     

基于NDVI时间序列的近12年中国植被覆盖的单调趋势分析

基于1999—2010年SPOT—VEGETATION旬值NDVI数据,并结合谐波分析、线性趋势和Kendall’sτ趋势等方法对中国各年植被生长季起止时刻进行了确定,并得到中国生长季植被覆盖的单调性趋势。结果表明:(1)1999—2010年中国植被覆盖呈明显增加趋势。中国植被覆盖变化存在4a的稳定增长期与1a的突然下降期。(2)中国生长季植被覆盖Kendall’sτ趋势平均值为0.287 3,总体上呈持续改善趋势,持续性较高的改善区主要分布在105°E以东,30°—40°N之间的区域。(3)中国植被覆盖受纬度地带性影响较为明显。纬度低,生物多样性程度较高的地区,则植被覆盖改善趋势明显,持续性强,反之改善趋势及持续性较低。黄三角和风沙区等生态脆弱区,长三角、珠三角与兰州市周边地区等经济快速发展区,植被覆盖退化严重。     

蝶形花亚科花发育的基因调控网络

植物千姿百态的花结构与其繁衍方式和生存环境密切相关,是其与传粉生物共同适应外界环境等共进化的结果。豆科植物种类众多,花型各异,为人类提供了丰富的食物和生活资源。蝶形花亚科作为豆科最大的亚科,与拟南芥等模式植物不同,蝶形花亚科植物存在复合花序、共同原基和不同对称性的花器官等复杂和精巧的结构及发育过程,为研究植物花发育的分子机制提供了丰富的材料。本文以当前研究比较深入的蝶形花亚科植物大豆、豌豆、蒺藜苜蓿和百脉根为例,介绍了豆科蝶形花亚科植物的花发育过程,重点总结了花分生组织属性决定、花序发育、花器官属性的决定和花型发育的基因调控网络,以期为豆科花发育研究和改良提供理论依据。

     

绿竹花发育相关BoAG-like基因的克隆与表达特性分析

AG基因属于MADS-box家族,在决定花分生组织特性和花器官发育中起着重要的作用。为阐明竹类植物AG基因的表达特性,本研究以绿竹开花试管苗花芽为植物材料,采用cDNA末端快速扩增技术(RACE),获得了完整的cDNA序列,命名为BoAG-like。序列分析结果表明,BoAG-like长度为792 bp,具有AG基因特有的AG Ⅰ区和AG Ⅱ区;BoAG-like与水稻OsMADS58、玉米ZAG1和毛竹PhMADS3的AG-like同源蛋白所编码的氨基酸序列同源性达到80%以上,均属于C类基因的eu-AG系;蛋白的三级结构预测结果表明,BoAG-like与水稻OsMADS58和二穗短柄草BdMADS18最为接近,但也存在明显差异;实时荧光定量PCR结果表明,BoAG-like基因在花器官的表达量明显高于营养器官的表达量,且其表达量随着绿竹花发育进程呈上升趋势;BoAG-like的表达量在绿竹花芽不同部位存在显著差异,其中在雌蕊中最高,外稃中最低。本研究结果为进一步深入研究竹子花发育的分子机制奠定了一定的理论基础。     

广西壮族自治区土地利用与土壤侵蚀的关系

[目的]对广西壮族自治区的土壤侵蚀现状进行定量分析,分析土地利用类型与土壤侵蚀的关系,为科学防治土壤侵蚀提供决策依据。[方法]以RUSLE模型为基础,引入喀斯特石漠化修正因子M,构建适合广西地区的土壤侵蚀模型。[结果](1)2015年,研究区土壤侵蚀模数为135.51t/(km~2·a),土壤侵蚀厚度达0.08mm/a,土壤侵蚀面积2.52×10~4 km~2,土壤侵蚀量3.21×10~7 t。其中,喀斯特地区土壤侵蚀面积1.86×10~4 km~2,占土壤侵蚀面积的73.81%,占总侵蚀量的31.01%。(2)土壤侵蚀量占总侵蚀量的大小顺序为:耕地(37.58%)林地(30.94%)草地(16.10%)园地(6.39%)工矿用地(4.09%)裸地(2.16%)。[结论]人类活动干扰强烈的土地利用影响全区土壤侵蚀空间分布格局。     

柚子花芳香油超临界CO2萃取研究

介绍了新鲜柚子花中芳香性成分超临界CO₂萃取分离工艺和分析检测方法,重点探讨了压力、温度、时间对萃取率的影响。应用正交试验优化得出：影响萃取的主次因素依次为为萃取压力、萃取温度、萃取时间;较佳工艺参数为：压力18 MPa,温度50℃,时间90 min,流量25 L/min,得到超临界柚子花芳香油的萃取率高达2.7‰。应用气相色谱-质谱联用仪共鉴定出39个组分,占总芳香油的91.281%。通过对柚子花的深度加工研究,为开发高附加值的柚子花香精提供科学依据。     

Yield and N assimilation of winter wheat (Triticum aestivum L., var. Norstar) inoculated with rhizobacteria

The effects of bacterial inoculants on the growth of winter wheat were studied in a growth chamber. Azospirillum brasilense, Azotobacter chroococcum, Bacillus polymyxa, Enterobacter cloacae, or a mixture of the four rhizobacteria were the inoculants tested. Inoculation effects on yield, yield components, and N-derived from fertilizer (Ndff) were assessed. The response of plants inoculated with individual bacteria was inconsistent and varied with treatment. At the first harvest (58 days after planting-DAP) plants inoculated with the mixture exhibited increases in plant dry weight, total-N and Ndff. At the second harvest (105 DAP), plants inoculated with A. brasilense and the mixture exhibited increases in shoot biomass, whereas at maturity (170 DAP), the inoculated plants showed no differences in total-N or shoot dry matter yield, as compared to the uninoculated controls. Inoculation with A. brasilense, however, increased the Ndff in the shoots, and B. polymyxa tended to enhance grain yield. Practical use of these rhizobacteria as inoculants for winter wheat may have limited value until such time as we better understand factors which influence rhizosphere competence of bacterial inoculants.     

On the Taxonomy of the Members of ‘Saccharum Complex’

The difficulty and problems encountered in the study of cultivated plants, in general and sugarcane, in particular has been indicated. In order to understand these problems, a brief review on the taxonomy of Saccharum and closely related taxa, namely, Erianthus, Sclerostachya, Narenga and Miscanthus (generally known as ‘Saccharum complex’) has been given. A short account on the important morphological features that are specific to sugarcane has also been stated as classification is commonly based on such morphological characters. A note has been added on the chromosome number, origin, and distribution of the species of ‘Saccharum complex’ members. Taxonomic keys have been devised for identification of the genera of Saccharinae and for the species of Saccharum and Erianthus occurring in India. A new combination, Sclerostachya fallax (Balansa) Amalraj et Balasundaram, has also been proposed.     

基质、处理剂及其浓度对黑果枸杞硬枝扦插育苗的影响

[目的]探索黑果枸杞硬枝扦插育苗对土壤环境的选择性,为优质苗木的工厂化生产提供技术参考。[方法]以甘肃省永靖县黑果枸杞一年生枝条为材料,对4种土壤基质中不同生根粉(BBT)和萘乙酸(NAA)处理浓度下黑果枸杞硬枝扦插后的成活率、生长状况、生根率及根系性状进行了测定和评价。[结果](1)泥炭土、壤土、沙土均可用作黑果枸杞硬枝扦插基质,各浓度BBT和NAA处理下的成活率均分别在95%和80%以上;沙盐土不宜用于黑果枸杞扦插育苗;(2)扦插后第10周,生根率最高的是泥炭土,其次是壤土,沙土最低,但沙土中已形成的根系在后期表现出快速生长的特点。(3)新生枝条长度在扦插后的前5周增长缓慢,之后显著增加;随育苗时间增长,植株间枝条生长量出现明显差异。[结论]从透气性和根系发育来看,泥炭土硬枝扦插的效果最好。从保水性来看,普通壤土和沙土均较好,但沙土生根率低,不建议使用。     

不同外源激素处理对桦叶四蕊槭扦插生根的影响

[目的]研究不同外源激素类型、不同浓度水平以及不同直径插穗对桦叶四蕊槭扦插生根的影响,为探寻高效繁殖体系以及为人工栽培和园林生产提供科学指导。[方法]利用扦插试验和统计分析方法开展研究。[结果](1)经过吲哚乙酸(IAA),吲哚丁酸(IBA),萘乙酸(NAA)和赤霉素(GA)这4种外源激素处理的插穗扦插生根率,均明显高于对照,其中IBA处理的效果最好;(2)在0~400mg/L这4个水平浓度中,IAA,IBA,NAA和GA分别在50,200,50,50mg/L时,所处理的插穗扦插达到其各自生根率的最大值;(3)粗插穗(D≥7mm)的平均生根率最高,达54%,其中以200mg/L的IBA处理效果最好,生根率达到77%。[结论]桦叶四蕊槭扦插生根的最优组合为,9月上旬,选用直径D≥7mm的插穗,用200mg/L的IBA处理。     

Genetic Diversity within and Between Populations of Lathyrus genus (Fabaceae) Revealed by ISSR Markers

In order to evaluate the genetic diversity in Lathyrus genus, the Inter Simple Sequence Repeats method (ISSR) was exploited in five populations. These consisted of two cultivated species belonging to section Lathyrus (L. sativus L. and L. cicera L.) and a wild one belonging to the section Clymenum (L. ochrus DC.). Two 3′anchored ISSR primers and two unanchored ones, generated a total of 60 useful polymorphic DNA bands. Our data provide evidence of high molecular polymorphism at the intra- and the inter-specific levels showing that both wild and cultivated forms constitute an important pool of diversity. Moreover, among the generated DNA bands, a 500 bp band, totally absent in the banding patterns of the section Clymenum, appears to be a molecular marker of section Lathyrus. Results provided for lineage and suggest recent origin of these species that might have evolved from a common ancestor producing both L. ochrus species and the two other species L. sativus and L. cicera. These relationships support previous studies based on morphological variation and molecular analysis.     

Development and validation of a quasi-Gaussian plume model for the transport of botanical spores

Aerial dispersal of inoculum is the primary means of movement for many plant diseases. One of the challenges of modern decision support for plant health is to provide predictions of the influx of viable pathogen inoculum from sources outside a crop. Such prediction in a practical setting requires prediction tools that have modest computing and input requirements, yet provide sufficiently accurate predictions. In this paper a hybrid dispersion model is developed, combining Taylor's statistical theory of diffusion for horizontal dispersal with the eddy diffusion theory as implemented in the Lagrangian similarity diffusion model of [van Ulden, A.P., 1978. Simple estimates for vertical diffusion from sources near the ground. Atmos. Environ. 12, 2119–2124] and [Gryning, S.E., van Ulden, A.P., Larsen, S.E., 1983. Dispersion from a continuous ground-level source investigated by a K model. Q. J. Roy. Meteor. Soc. 109, 355–364]. The model is extended with a dry deposition method and an effective source strength. Model results are compared with experimental data for the transport of artificially released spores of Lycopodium clavatum above a potato canopy. The numerical results are in close agreement with the experimental data, which cover distances up to 100 m. Numerical predictions are compared to those produced by two alternative model versions and a previously published Gaussian plume model for the transport of spores above potato canopies. The potential for practical implementation of atmospheric dispersion models in plant disease decision support systems is discussed.     

Genetic diversity of rhizobia associated with indigenous legumes in different regions of Flanders (Belgium)

We investigated the diversity of rhizobia isolated from different indigenous legumes in Flanders (Belgium). A total of 3810 bacterial strains were analysed originating from 43 plant species. Based on rep-PCR clustering, 16S rRNA gene and recA gene sequence analysis, these isolates belonged to Bradyrhizobium, Ensifer (Sinorhizobium), Mesorhizobium and Rhizobium. Of the genera encountered, Rhizobium was the most abundant (62%) and especially the species Rhizobiumleguminosarum, followed by Ensifer (19%), Bradyrhizobium (14%) and finally Mesorhizobium (5%). For two rep-clusters only low similarity values with other genera were found for both the 16S rRNA and recA genes, suggesting that these may represent a new genus with close relationship to Rhodopseudomonas and Bradyrhizobium. Primers for the symbiotic genes nodC and nifH were optimized and a phylogenetic sequence analysis revealed the presence of different symbiovars including genistearum, glycinearum, loti, meliloti, officinalis, trifolii and viciae. Moreover, three new nodC types were assigned to strains originating from Ononis, Robinia and Wisteria, respectively. Discriminant and MANOVA analysis confirmed the correlation of symbiosis genes with certain bacterial genera and less with the host plant. Multiple symbiovars can be present within the same host plant, suggesting the promiscuity of these plants. Moreover, the ecoregion did not contribute to the separation of the bacterial endosymbionts. Our results reveal a large diversity of rhizobia associated with indigenous legumes in Flanders. Most of the legumes harboured more than one rhizobial endosymbiont in their root nodules indicating the importance of including sufficient isolates per plant in diversity studies.