北京地区野生草种资源及其开发利用

本文论述了北京市的野生草种资源及其利用现状,分析了北京市开发野生草种的前景,指出北京市在野生草种的开发利用中,应重点加强野生草种的引种驯化、野生草种的新品种选育,确定野生草种的发展方面,加强宣传,增强人们对野生草种的认识,保护性的开发利用野生草种等工作,使之成为北京市的主要产业之一.     

GROWTH OF CYMBOPOGON CITRATUS AND VETIVERIA ZIZANIOIDES ON Cu MINE TAILINGS AMENDED WITH CHICKEN MANURE AND MANURE-SOIL MIXTURES: A POT SCALE STUDY

The Rakha Cu mines are located at East Singhbhum, Jharkhand, India and their activities ceased in 2001. The tailings (residue) were permanently stored in tailings ponds that require vegetation to reduce their impact on the environment. A pot scale study was conducted to evaluate the suitability of Cymbopogon citratus (DC.) Ex Nees and Vetiveria zizanioides (L.) Nash for the reclamation of Cu tailings and to evaluate the effects of chicken manure and soil-manure mixtures on the revegetation of such tailings. Application of manure and soil-manure mixtures resulted in significant increase in pH, EC, OC, CEC and nutritional status of Cu tailings. The environmentally available and DTPA extractable Cu and Ni concentration reduced in amended tailings, while Mn and Zn content increased significantly. Plants grown on amended tailings accumulated lesser Cu and Ni but higher Mn and Zn. Plant biomass increased proportionally to manure and soil-manure mixtures application rates. Lemon grass produced more biomass than vetiver grass in either of the amended tailings. From the pot experiment, it can be suggested that application of chicken manure @ 5% (w/w) and in combination with lemon grass, could be a viable option for reclamation (phytostabilization) of toxic tailings.     

辐射处理对冷季型草幼穗分化的影响

以C60Or射线对一年生黑麦草(品种:冠军)、多年生黑麦草(品种:爱神特)、早熟禾(品种:歌来德)及高羊茅(品种:知音)4个禾本科草坪草干种子进行辐照,剂量分别是15000rad(处理Ⅰ)、25000rad(处理Ⅱ)、35000rad(处理Ⅲ).播种生长后,田间取样观察;实验结果表明,所用剂量对冷季型草的幼穗分化进程影响不大,相对而言高剂量对多年生黑麦草的生殖生长有一定延长作用.     

Neotropical C3/C4 grass distributions – present,past and future

Changes in C₄ grass distribution and abundance are frequently observed in Quaternary, Holocene and future environmental‐change scenarios. However, the factors driving these dynamics are not fully understood, and conflicting theories have been reported. In this paper, we present a very large dataset of modern altitudinal distribution profiles of C₃ and C₄ grasses covering the entire Neotropical Andes, which was compared with actual climate data. The results of multivariate analysis demonstrate that, in the Neotropical Andes, mean annual temperature is the main factor governing the modern altitudinal distribution of C₃ and C₄ grass species. The C₃ and C₄ grass distributions were compared with simulations based on the Lund‐Potsdam‐Jena dynamic global vegetation model (LPJ‐DGVM), which allowed the present grass distribution to be estimated. Finally, the DGVM was employed to simulate past and future scenarios, using the IPCC's climate projections for 2100 and PMIP2 models for the Holocene Optimum (HO, 6000 years bp ) and the Last Glacial Maximum (LGM, 21 000 years bp ). The results were found to be significantly different from those obtained using a simple photosynthetic model. According to LPJ forced with the PMIP2 models for the LGM, during the LGM, the C₄ grasses would not have reached higher altitudes than found in the present day.     

气候条件对典型草原牧草生长发育影响浅析

采用兴安盟扎赉特旗2004年～2011年气候生态环境监测站监测的典型草原牧草生长发育及地上生物量等基本资料。典型草原主要牧草种类有贝加尔针茅、野古草、羊草等禾草,伴生中旱生杂草、灌木及半灌木组成,草丛一般高30～50 cm。本文详细分析了当地气候条件对典型草原牧草生长发育及产量的影响。结果表明,典型草原牧草的高度、盖度及地上生物量受温度和降水量影响最明显,其中降水量的影响超过温度的影响。降水量多的年份地上生物量明显增加,而干旱年份地上生物量减少,其最大值一般出现在7月份,并滞后于降水量最大值。     

香根草属与狼尾草属植物对土壤线虫营养类群的影响?

对广州华南植物园香根草属泰国香根草(Vetiveria nemoralis)、普通香根草(V.zizanoides)的2个品种Sunshine和Karnataka以及狼尾草属象草(Pennisetum purpureum)、皇草(P.purpureum×P.thyphoides)和杂交狼尾草(P.americanum×P.purpureum)的地下土壤线虫各食性类群在根区和非根区的分布特征进行了对比研究,结果表明:线虫主要集中在0-15 cm的浅层土壤中,在不同生境下食细菌和植物寄生性线虫占优势,两类线虫的比例在香根草属植物生境下为87.7%-97.6%,狼尾草属植物生境下为88.5%-94.0%,而食真菌、捕食性和杂食性线虫数量则很少,其相应的比例分别为2.4%-12.3%和6.0%-11.5%。两属植物根区的线虫数量显著高于非根区,但不同营养类群的线虫在根区和非根区的分布有较大差异。香根草属植物和杂交狼尾草非根区植物寄生性线虫的比例高于根区,而食细菌线虫的比例低于根区;但象草和皇草非根区植物寄生性线虫的比例低于根区,而食细菌线虫的比例高于根区。除皇草外,两属植物非根区食真菌线虫的比例一般高于根区。在所选的植物中,Karnataka和杂交狼尾草在土壤改良和土壤生物学效应方面有更好的潜力。     

百喜草及其在南方果园生草栽培和草被体系中的应用

果园立地条件差、土壤肥力不足是影响我国果树产量和果实品质的重要因素。百喜草是优良的果园生草栽培和草被体系草种。在我国南方果产区推广应用百喜草,对于防止水土流失、改善果园生态环境、培肥果园土壤、提高果实产量和品质具有重要意义。     

Utilization of Grasses for Potential Biofuel Production and Phytoremediation of Heavy Metal Contaminated Soils

This research focuses on investigating the use of common biofuel grasses to assess their potential as agents of long-term remediation of contaminated soils using lead as a model heavy metal ion. We present evidence demonstrating that switch grass and Timothy grass may be potentially useful for long-term phytoremediation of heavy metal contaminated soils and describe novel techniques to track and remove contaminants from inception to useful product. Enzymatic digestion and thermochemical approaches are being used to convert this lignocellulosic feedstock into useful product (sugars, ethanol, biocrude oil + biochar). Preliminary studies on enzymatic hydrolysis and fast pyrolysis of the Switchgrass materials that were grown in heavy metal contaminated soil and non-contaminated soils show that the presence of lead in the Switchgrass material feedstock does not adversely affect the outcomes of the conversion processes. These results indicate that the modest levels of contaminant uptake allow these grass species to serve as phytoremediation agents as well as feedstocks for biofuel production in areas degraded by industrial pollution.     

Recent advances in genetic transformation of forage and turf grasses

Summary Forage and turf grasses are critical to sustainable agriculture and contribute extensively to the world economy. Tremendous progress has been made in genetic transformation of forage and turf grasses in the past decade. The rapid advancement of cellular and molecular biology and transgenic technology provides novel methods to accelerate and complement conventional breeding efforts. This review summarizes the latest developments in genetic transformation methods and the applications of molecular techniques for the improvement of forage and turf grasses.     

Endophyte-mediated disease resistance in wild populations of perennial ryegrass (Lolium perenne)

Twelve wild, endophyte-infected populations of perennial ryegrass were tested for resistance against artificial infection of Drechslera siccans and Fusarium spp. Plants with identified endophyte presence (E+), together with plants free from endophytes (E−), were inoculated with serious turf grass pathogens: D. siccans (cause of brown blight) and a mixture of Fusarium species (cause of Fusarium blight). For both diseases, the positive effect of endophyte presence on plant resistance was observed. In the case of a few ecotypes, endophyte infection increased resistance against both diseases, which is of practical importance for disease control.     

Inheritance of transgenes in transgenic tall fescue (<Emphasis Type="Italic">Festuca arundinacea</Emphasis> schreb.)

Summary Tall fescue (Festuca arundinacea Schreb.) is the most important forage species worldwide of the Festuca genus. Single genotype-derived embryogenic suspension cultures were established from tall fescue cultivar Kentucky-31, and were used as target cells for biolistic transformation. A chimeric hygromycin phosphotransferase gene (hph) was used as the selectable marker, and a chimeric β-glucuronidase (gusA) gene was co-transformed with hph. Transgenic plants were recovered after microprojectile bombardment of suspension cells and subsequent selection in the presence of a high concentration of hygromycin. Fertile transgenic plants were obtained after vernalization under field conditions. T1 and T2 progenies were obtained after reciprocal crosses between transgenic and untransformed control plants. PCR and Southern hybridization analyses revealed a 1∶1 segregation ratio for both transgenes in the T1 and T2 generations. Southern hybridization patterns were identical for T0, T1, and T2 plants. The results demonstrated for the first time the stable meiotic transmission of transgenes following Mendelian rules in transgenic tall fescue.     

Redescription and Lectotype Designation of Tylenchorhynchus cylindricus Cobb, 1913

Tylenchorhynchus cylindricus is redescribed and illustrated from N. A. Cobb''s original specimens collected in 1910. In 1955 M. W. Allen established a neotype from specimens collected near Cathedral City, California. Recently Cobb''s original sketches, line drawings, and balsam slides were rediscovered and examined. The specimens collected by Cobb were compared with the neotype established by Allen and with other collections of nominal T. cylindricus. Differences in morphology of the Cathedral City (Allen) and Los Patos (Cobb) populations were observed. Collections of males and females from Cathedral City, California; Mosida, Utah; and Kings County, California; were similar to each other except for some variation in female tail shape. Females in Cobb''s collection and in a collection from a beach near Ensenada, Mexico, were similar to each other but differed morphologically from other collections. We consider all collections to represent a range of variation within the species. A lectotype and an allolectotype were selected to establish the taxonomic base for the genus. A ruling has been requested from the International Commission of Zoological Nomenclature on the disposition of the neotype.     

City spore concentrations in the European Economic Community (EEC). VI. Poaceae (Grasses), 1982–1986

Summary Airborne grass-pollen concentrations in six cities in the EEC are compared, based on observations from five years, 1982–1986. Results show that there are quantitative differences both between the monitoring stations and between the years. Very provisionally, the average seasonal total of the European urban airborne grass-pollen concentration can be put at 4 to 5000 per m³ of air. Also qualitatively, regarding the seasonal fluctuations, there are differences between the stations, and between the years. Generally, the results confirm that June is the most typical grass-pollen month in northwestern Europe, whereas in mediterranean Europe May is the more prominent grass-pollen period. There seems to be little coherence between the starting dates of the grass-pollen season even at relatively nearby stations in northwestern Europe, suggestive for a great influence of the actual weather situation.     

Contrasting impacts of grass species on nitrogen cycling in a grazed Sudanian savanna

We investigated the impact of perennial and annuals grass species on nitrogen cycling in a Sudanian savanna of Burkina Faso. We also analysed how the local context in terms of grazing and soil properties modifies these impacts. We selected four plots differing both by the intensity of grazing by cattle and soil depth, and used soil and grass biomass ¹⁵N as integrative indicators of N cycle. If perennials are able to foster a more efficient nitrogen cycling there should be lower ¹⁵N abundances in their biomass and soil. If soil depth and cattle pressure significantly modify nitrogen fluxes, soil depth and cattle pressure should influence ¹⁵N signatures. Our results suggest that perennial grasses are more conservative for nitrogen (inhibition of nitrification, less leaching via a perennial root system, slower cycling). The increase in leaf δ¹⁵N with N concentration is steeper in Loudetia togoensis than in the three other grasses. No significant difference was found between the ¹⁵N signatures of the four plots. Our results on ¹⁵N signatures and the fact that perennial grasses are much more abundant in the plots that are less grazed and have deeper soils, confirm that the switch from perennial to annual grasses is linked to a degradation in soil fertility and pasture quality. This suggests that ¹⁵N signatures can be used as indicators of fertility.     

Microbial colonization and degradation of forage samples incubated in vitro at different initial pH

Microbial colonization, degradation, and gas production kinetics of tropical and temperate forage samples incubated in vitro at initial pH (pHi) of 5.5, 6.0, 6.5 and 7.0 were measured. Dried, ground samples of oat (Avena strigosa), ryegrass (Lolium multifllorum), dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott.) and ricegrass (Echinochloa sp.) were used. Microbial colonization on residues and extent of degradation were higher for temperate than for tropical forage samples (P<0.05). Initial pH did not affect microbial colonization on residue, but the extent of in vitro degradation was directly related to pHi for both forage types (P<0.05). Kinetics of fermentation of temperate and tropical forage samples, however, reacted differently to both the incubation method (i.e., in vitro or in vitro/gas) and the pHi.     

Changes in stomatal conductance along grass blades reflect changes in leaf structure

Identifying the consequences of grass blade morphology (long, narrow leaves) on the heterogeneity of gas exchange is fundamental to an understanding of the physiology of this growth form. We examined acropetal changes in anatomy, hydraulic conductivity and rates of gas exchange in five grass species (including C(3) and C(4) functional types). Both stomatal conductance and photosynthesis increased along all grass blades despite constant light availability. Hydraulic efficiency within the xylem remained constant along the leaf, but structural changes outside the xylem changed in concert with stomatal conductance. Stomatal density and stomatal pore index remained constant along grass blades but interveinal distance decreased acropetally resulting in a decreased path length for water movement from vascular bundle to stomate. The increase in stomatal conductance was correlated with the decreased path length through the leaf mesophyll. A strong correlation between the distance from vascular bundles to stomatal pores and stomatal conductance has been identified across species; our results suggest this relationship also exists within individual leaves.     

Divergent climate impacts on C3 versus C4 grasses imply widespread 21st century shifts in grassland functional composition

Aim

Grasslands cover a third of Earth's landmass and provide critical ecosystem services. Anticipating how perennial C₃ (cool-season) and C₄ (warm-season) grasses respond to climate change will be key to predicting future composition and functioning of grasslands. Here, we evaluate environmental drivers of C₃ and C₄ perennial distributions and assess how C₃ and C₄ grass distributions shift in response to future climate change.

Location

Western United States.

Methods

We developed integrated species distribution models to identify climate and soil drivers of relative abundance of C₃ and C₄ perennial grasses. We then created projections of species abundances under future climate and evaluated when and where projected shifts in relative abundance were robust across climate models.

Results

Historically, C₃ grasses occupied areas with lower temperature and more variable precipitation regimes, while C₄ grasses occupied areas of higher temperature, greater temperature variability and greater warm-season precipitation. C₄ species also occupied narrower soil texture niches. In response to future climate change, C₃ grass abundance declined across 74% of areas, while C₄ abundance increased across 66% of areas. C₃ grasses expanded in mid- to higher-latitude areas with increasing temperature and decreasing seasonality of precipitation. In contrast, C₄ grasses increased in higher-latitude regions, but declined in lower-latitude, dryer regions. Results were surprisingly robust across climate scenarios, suggesting high confidence in the direction of these future changes.

Main Conclusions

Findings imply C₃ and C₄ perennial grasses will have highly divergent responses to climate change that may result in grassland functional compositional changes. Increasing temperatures and precipitation variability may favour some C₄ grasses, but C₄ habitat expansion may be constrained by soil conditions in western USA. Results provide actionable insights for anticipating the impacts of climate change on grass-dominated and co-dominated ecosystems and improving large-scale conservation and restoration efforts.     

The growth and nitrogen uptake of Rhodes grass grown on soils with varying histories of legume cropping

Summary Rhodes grass (Chloris gayana) was grown under glasshouse conditions on soils that had previously grown from 1 to 6 soybean (Glycine max) or Siratro (Macroptillium atropurpureum) crops. Soil mineral N contents at sowing were higher in Siratro-cropped than soybean-cropped soils and increased with cropping history.Yields of Rhodes grass at the first harvest (14 weeks) were related to soil mineral N levels at sowing by the relationship Y=138.7 (1–0.917e^–0.012x). Grass grown on all soybean soils was responsive to N at both harvests (14 and 28 weeks). Grass grown on soil that had grown three or more Siratro crops was non-responsive to N at the first harvest but responses to N were recorded on all Siratro soils at the second harvest.The amount of N removed by the grass crops was small in relation to the total amount present in the soil system. This resulted in no change in soil total N levels over the two crop periods.These results highlight the need to study N dynamics in crop systems rather than continue to measure N pool sizes when evaluating the contribution of biologically fixed N to the nutrition of subsequent non-legume crops.     

稗草DNA的快速提取研究

优化了稗草DNA的提取条件,水浴时间为60min,无水乙醇用量为0.60ml,细胞提取液用量为6．0ml,饱和NaAc溶液用量为1.0ml,酚／氯仿／异戊醇溶液、氯仿／异戊醇溶液和异丙醇与样液体积比别为0．60、1．0和0．60。从稗草种子提取时,产率为430μg／g。琼脂糖凝胶电泳证实,所提稗草DNA无断裂降解。