厦门地区高尔夫球场草种选择与绿化布局的初步探讨

本文就厦门地区高尔夫球场草种选择和绿化问题作了初步探讨。作者认为,厦门地区的自然条件适合暖地型草种的生长,草种应以狗牙根(Cynodon spp.)和结缕草(Zoysia spp.)为主。绿化设计应体现南亚热带滨海风光的植被景观,树种配置以亚热带植物为主,并与引种的树种相结合,注意绿化效果和球场功能的协调统一,做到绿化布局合理,以绿化效果衬托球场草坪的美观。     

Feed intake and milk production in dairy cows fed different grass and legume species: a meta-analysis

The aim of this meta-analysis was to compare feed intake, milk production, milk composition and organic matter (OM) digestibility in dairy cows fed different grass and legume species. Data from the literature was collected and different data sets were made to compare families (grasses v. legumes, Data set 1), different legume species and grass family (Data set 2), and different grass and legume species (Data set 3+4). The first three data sets included diets where single species or family were fed as the sole forage, whereas the approach in the last data set differed by taking the proportion of single species in the forage part into account allowing diets consisting of both grasses and legumes to be included. The grass species included were perennial ryegrass, annual ryegrass, orchardgrass, timothy, meadow fescue, tall fescue and festulolium, and the legume species included were white clover, red clover, lucerne and birdsfoot trefoil. Overall, dry matter intake (DMI) and milk production were 1.3 and 1.6 kg/day higher, respectively, whereas milk protein and milk fat concentration were 0.5 and 1.4 g/kg lower, respectively, for legume-based diets compared with grass-based diets. When comparing individual legume species with grasses, only red clover resulted in a lower milk protein concentration than grasses. Cows fed white clover and birdsfoot trefoil yielded more milk than cows fed red clover and lucerne, probably caused by a higher OM digestibility of white clover and activity of condensed tannins in birdsfoot trefoil. None of the included grass species differed in DMI, milk production, milk composition or OM digestibility, indicating that different grass species have the same value for milk production, if OM digestibility is comparable. However, the comparison of different grass species relied on few observations, indicating that knowledge regarding feed intake and milk production potential of different grass species is scarce in the literature. In conclusion, different species within family similar in OM digestibility resulted in comparable DMI and milk production, but legumes increased both DMI and milk yield compared with grasses.     

Seed dispersal in the dung of large herbivores: implications for restoration of Renosterveld shrubland old fields

Species-rich, winter-rainfall, microphyllous Renosterveld vegetation in the Western Cape Province of South Africa has largely been transformed for production of wheat and wine. Remaining fragments thus have high conservation value. Abandoned old fields adjacent to natural vegetation fragments could potentially be restored as corridors and habitat for indigenous flora and fauna. We hypothesised that indigenous antelope maintained in a matrix of natural vegetation and abandoned field could play a role in restoration of Renoserveld via seed dispersal.We collected dung of indigenous ungulates in an abandoned field at various distances from natural Renosterveld vegetation, in order to assess the potential of large herbivores to contribute to restoration of plant diversity through seed dispersal. Emerged seedlings from the collected dung represented 29 forb, 13 grass, four sedge, four geophyte and one shrub species. The most abundant emerging seedlings were lawn grass Cynodon dactylon (38%), alien pasture grasses (31%) and indigenous geophyte Romulea rosea (12%). Whereas seeds of annual forbs and grasses were dispersed, only one shrub species was dispersed at very low density. We concluded that large herbivores could retard the rate of recovery of Renosterveld vegetation because viable seeds of herbaceous plants, particularly alien annual grasses and lawn-grasses were more abundant in the dung than the shrub, geophyte or perennial tussock grass species that characterise this vegetation type.     

Effects of exotic annual grass litter and local environmental gradients on annual plant community structure

Exotic annual grasses have been introduced into many semi-arid ecosystems worldwide, often to the detriment of native plant communities. The accumulation of litter from these grasses (i.e. residual dry biomass) has been demonstrated to negatively impact native plant communities and promote positive feedbacks to exotic grass persistence. More targeted experiments are needed, however, to determine the relative impact of exotic grass litter on plant community structure across local environmental gradients. We experimentally added exotic grass litter to annual forb-dominated open woodland communities positioned along natural canopy cover gradients in southwest Western Australia. These communities are an important component of this region’s plant biodiversity hotspot and are documented to be under threat from exotic annual grasses. After a one-year treatment period, we measured the effects of exotic grass litter, soil properties, and canopy cover on native and exotic species richness and abundance, as well as common species’ biomass and abundances. Plant community structure was more strongly influenced by soil properties and canopy cover than by grass litter. Total plant abundances per plot, however, were significantly lower in litter addition plots than control plots, a trend driven by native species. Exotic grass litter was also associated with lower abundances of one very common native species: Waitzia acuminata. Our results suggest that exotic grass litter limits the establishment of some native species in this system. Over multiple years, these subtle impacts may contribute substantially to the successful advancement of exotic species into this system, particularly in certain microenvironments.     

Aboveground productivity and root–shoot allocation differ between native and introduced grass species

Plant species in grasslands are often separated into groups (C₄ and C₃ grasses, and forbs) with presumed links to ecosystem functioning. Each of these in turn can be separated into native and introduced (i.e., exotic) species. Although numerous studies have compared plant traits between the traditional groups of grasses and forbs, fewer have compared native versus introduced species. Introduced grass species, which were often introduced to prevent erosion or to improve grazing opportunities, have become common or even dominant species in grasslands. By virtue of their abundances, introduced species may alter ecosystems if they differ from natives in growth and allocation patterns. Introduced grasses were probably selected nonrandomly from the source population for forage (aboveground) productivity. Based on this expectation, aboveground production is predicted to be greater and root mass fraction to be smaller in introduced than native species. We compared root and shoot distribution and tissue quality between introduced and native C₄ grass species in the Blackland Prairie region of Central Texas, USA, and then compared differences to the more well-studied divergence between C₄ grasses and forbs. Comparisons were made in experimental monocultures planted with equal-sized transplants on a common soil type and at the same density. Aboveground productivity and C:N ratios were higher, on average, in native grasses than in native forbs, as expected. Native and introduced grasses had comparable amounts of shallow root biomass and tissue C:N ratios. However, aboveground productivity and total N were lower and deep root biomass and root mass fraction were greater in native than introduced grasses. These differences in average biomass distribution and N could be important to ecosystems in cases where native and introduced grasses have been exchanged. Our results indicate that native–introduced status may be important when interpreting species effects on grassland processes like productivity and plant N accumulation.     

Remodeling of chloroplast proteome under salinity affects salt tolerance of <Emphasis Type="Italic">Festuca arundinacea</Emphasis>

Acclimation of photosynthetic apparatus to variable environmental conditions is an important component of tolerance to dehydration stresses, including salinity. The present study deals with the research on alterations in chloroplast proteome of the forage grasses. Based on chlorophyll fluorescence parameters, two genotypes of a model grass species—Festuca arundinacea with distinct levels of salinity tolerance: low salt tolerant (LST) and high salt tolerant (HST), were selected. Next, two-dimensional electrophoresis and mass spectrometry were applied under both control and salt stress conditions to identify proteins accumulated differentially between these two genotypes. The physiological analysis revealed that under NaCl treatment the studied plants differed in photosystem II activity, water content, and ion accumulation. The differentially accumulated proteins included ATPase B, ATP synthase, ribulose-1,5-bisphosphate carboxylase large and small subunits, cytochrome b6-f complex iron-sulfur subunit, oxygen-evolving enhancer proteins (OEE), OEE1 and OEE2, plastidic fructose-bisphosphate aldolase (pFBA), and lipocalin. A higher level of lipocalin, potentially involved in prevention of lipid peroxidation under stress, was also observed in the HST genotype. Our physiological and proteomic results performed for the first time on the species of forage grasses clearly showed that chloroplast metabolism adjustment could be a crucial factor in developing salinity tolerance.     

Herbaceous Forage and Selection Patterns by Ungulates across Varying Herbivore Assemblages in a South African Savanna

Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African savanna in and adjacent to the Kruger National Park, South Africa. We compared mixed and mono-specific herbivore assemblages of varying density and investigated similarities in vegetation patterns under wildlife and livestock herbivory. Grass species composition differed significantly, standing biomass and grass height were almost twice as high at sites of low density compared to high density mixed wildlife species. Selection of various grass species by herbivores was positively correlated with greenness, nutrient content and palatability. Nutrient-rich Urochloa mosambicensis Hack. and Panicum maximum Jacq. grasses were preferred forage species, which significantly differed in abundance across sites of varying grazing pressure. Green grasses growing beneath trees were grazed more frequently than dry grasses growing in the open. Our results indicate that grazing herbivores appear to base their grass species preferences on nutrient content cues and that a characteristic grass species abundance and herb layer structure can be matched with mammalian herbivory types.     

Photoperiodic requirements for LH release in juvenile broiler and egg-laying strains of domestic chickens fed ad libitum or restricted diets

Photoperiodic response curves for LH release were obtained for juvenile female domestic chickens at 8 weeks of age by measuring changes in plasma LH concentrations after increasing the daily photoperiod from 8 to 10.5, 12.75, 15.25, 17.75 or 20 h. The birds were bred either for meat production (broiler) or commercial egg-laying and were fed ad libitum or a restricted diet, similar to that used under commercial conditions. Ovarian and oviduct growth was stimulated by 2 weeks after transfer to 20 h light/day in the dwarf broiler strain, irrespective of the dietary treatment, but not in birds of the egg-laying strain. Baseline concentrations of plasma LH were higher in the egg-laying than in the dwarf broiler strain birds. A significant effect of dietary treatment was observed on the changes in concentration of plasma LH in the nonphotostimulated dwarf broiler, but not in the egg-laying bird. There was no significant interaction between dietary treatment and photoinduced LH release in birds of either strain. The shortest photoperiod needed to stimulate LH release (critical daylength) was less than 10.5 h in the dwarf broilers and between 10.5 and 12.75 h in the egg-laying birds. The shortest photoperiod needed to stimulate the maximum release of LH (saturation daylength) was between 10.5 and 12.75 h in the dwarf broiler strain. The saturation daylength in birds of the egg-laying strain was longer, being between 12.75 and 15.25 h.(ABSTRACT TRUNCATED AT 250 WORDS)     

Forage and Turf Grass Biotechnology

Referee: Dr. Ian Ray, Plant Breeding and Genetics, Department of Agronomy & Horticulture, New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM 88003-8003 Forage and turf grasses are the backbone of sustainable agriculture and contribute extensively to the world economy. They play a major role in providing high quality and economical meat, milk, and fiber products and are important in soil conservation, environmental protection, and outdoor recreation. Conventional breeding contributed substantially to the genetic improvement of forage and turf grasses in the last century. The relatively new developments in genetic manipulation of these species open up opportunities for incorporating cellular and molecular techniques into grass improvement programs. For some commonly used forage and turf species, significant advances have been achieved in the following areas: (1) establishment of a tissue culture basis for the efficient regeneration of fertile and genetically stable plants, (2) generation of transgenic plants by biolistic transformation and direct gene transfer to protoplasts, (3) recovery of intergeneric somatic grass plants by protoplast fusion, (4) development of molecular markers for marker assisted selection, and (5) sequencing of expressed sequenced tags and the development of DNA array technologies for gene discovery. Although difficulties still exist in genetic manipulation of these recalcitrant monocot species, impressive progress has been made toward the generation of value-added novel grass germplasm incorporating traits such as improved forage quality. The joint efforts of molecular biologists and plant breeders make the available biotechnological methods a useful tool for accelerating forage and turf grass improvement.     

Impacts of savanna trees on forage quality for a large African herbivore

Recently, cover of large trees in African savannas has rapidly declined due to elephant pressure, frequent fires and charcoal production. The reduction in large trees could have consequences for large herbivores through a change in forage quality. In Tarangire National Park, in Northern Tanzania, we studied the impact of large savanna trees on forage quality for wildebeest by collecting samples of dominant grass species in open grassland and under and around large Acacia tortilis trees. Grasses growing under trees had a much higher forage quality than grasses from the open field indicated by a more favourable leaf/stem ratio and higher protein and lower fibre concentrations. Analysing the grass leaf data with a linear programming model indicated that large savanna trees could be essential for the survival of wildebeest, the dominant herbivore in Tarangire. Due to the high fibre content and low nutrient and protein concentrations of grasses from the open field, maximum fibre intake is reached before nutrient requirements are satisfied. All requirements can only be satisfied by combining forage from open grassland with either forage from under or around tree canopies. Forage quality was also higher around dead trees than in the open field. So forage quality does not reduce immediately after trees die which explains why negative effects of reduced tree numbers probably go initially unnoticed. In conclusion our results suggest that continued destruction of large trees could affect future numbers of large herbivores in African savannas and better protection of large trees is probably necessary to sustain high animal densities in these ecosystems.     

Use of tall fescue EST-SSR markers in phylogenetic analysis of cool-season forage grasses.

Microsatellites or simple sequence repeats (SSRs) are highly useful molecular markers for plant improvement. Expressed sequence tag (EST)-SSR markers have a higher rate of transferability across species than genomic SSR markers and are thus well suited for application in cross-species phylogenetic studies. Our objectives were to examine the amplification of tall fescue EST-SSR markers in 12 grass species representing 8 genera of 4 tribes from 2 subfamilies of Poaceae and the applicability of these markers for phylogenetic analysis of grass species. About 43% of the 145 EST-SSR primer pairs produced PCR bands in all 12 grass species and had high levels of polymorphism in all forage grasses studied. Thus, these markers will be useful in a variety of forage grass species, including the ones tested in this study. SSR marker data were useful in grouping genotypes within each species. Lolium temulentum, a potential model species for cool-season forage grasses, showed a close relation with the major Festuca-Lolium species in the study. Tall wheat grass was found to be closely related to hexaploid wheat, thereby confirming the known taxonomic relations between these species. While clustering of closely related species was found, the effectiveness of such data in evaluating distantly related species needs further investigations. The phylogenetic trees based on DNA sequences of selected SSR bands were in agreement with the phylogenetic relations based on length polymorphism of SSRs markers. Tall fescue EST-SSR markers depicted phylogenetic relations among a wide range of cool-season forage grass species and thus are an important resource for researchers working with such grass species.     

呼伦贝尔草地野生禾本科牧草资源及资源评价

对呼伦贝尔草地野生禾本科牧草的属种组成、生长习性及饲用价值进行了研究。结果表明,呼伦贝尔草地现有禾本科牧草42属112种,这些禾本科牧草大多为多年生草本植物,适应典型草原和丘陵草甸草原生境,饲用价值高,适口性良好,是植被组成中的重要组成成分,生态利用前景广阔,是本地区重要的牧草资源。对其资源进行评价,为其合理开发利用提供理论依据。     

Particle inflow gun-mediated transformation of multiple-shoot clumps in rhodes grass (Chloris gayana)

Rhodes grass (Chloris gayana) is one of the most important warm-season forage grasses. It is cultivated in tropical and subtropical parts of the world and is mostly used for grazing and hay production. We have established a particle-bombardment transformation protocol for rhodes grass using multiple-shoot clumps (MSCs) as the target tissue. A vector pAHC25 containing a herbicide-resistance gene (bar) together with the beta-glucuronidase (GUS) gene was used in transformation experiments. The most efficient recovery of bialaphos-resistant tissue was achieved when the bombarded MSCs were first cultured for 15 d on bialaphos-free medium before being subjected to selection pressure. The resistant tissues regenerated transgenic plants that displayed GUS gene expression. Under optimized conditions, 251 target pieces yielded 46 transgenic plants from 4 independent transgenic lines.     

Reproductive diapause and quiescence in a tropical rice buh,Leptocorisa oratorius

Experiments were carried out to analyze the effects of food supply and photoperiod on the induction of dormancy inLeptocorisa oratorius Fabricius (Heteroptera: Alydidae) adults in Alor Setar (latitude 6.1^o N), West Malaysia. When the adults were deprived of food, they ceased oviposition, became tolerant to starvation, and their oxygen consumption rate decreased, but they did not accumulate lipid. Their oxygen consumption rate again increased when they were allowed to resume feeding. Therefore, food limitation induced quiescence in the adult. On the other hand, diapause was induced by short daylength (critical photoperiod was 12L:12D), leading to immature ovaries, hypertrophied fat bodies, lipid accumulation and low oxygen consumption rate even when food was available. However, in the study area most of the bugs probably did not enter diapause at any time of the year, because the shortest outdoor daylength including civil twilight was longer than the critical daylength for diapause induction.     

Photoperiod gene control over partitioning between reproductive and vegetative growth

Summary The hypothesis tested was that lack of photoperiod gene activity allows inherent partitioning of photosynthate to continued growth of the earliest potential buds, flowers, pods, and seeds (the organs that give rise to the yield). Alternatively, and competitively, photoperiod gene activity causes the photosynthate to be partitioned predominantly toward continued growth of new vegetative organs plus later initiation of more reproductive (yield) organs. This hypothesis was tested by comparing an insensitive and a photoperiod-sensitive bean (Phaseolus vulgaris L.) cultivar and their F₁ with F₂ segregates of undetermined genotype. Randomly derived homozygous F₈ segregates were also compared. The F₈ generation included one photoperiod-insensitive and one photoperiod-sensitive genotype in a 1:1 ratio, which verified control by one photoperiod gene. Under long daylength (LD), in addition to early versus late flowering and maturity, the two genotypes expressed opposite levels of 23 other traits that would be changed by competitive partitioning of the photosynthate. In contrast, under short daylength (SD), both genotypes flowered and matured early, and both expressed the levels for all 25 traits that the photoperiod-insensitive genotype expressed in both SD and LD. The photoperiod gene interacted with daylength to control the levels of all three major physiological components of yield: the aerial biomass, harvest index, and days to maturity. Included among the other traits with levels altered by daylength-modulated photoperiod gene activity were: the number of branches, nodes, leaves and leaf area, the rate of yield accumulation, and sink activity.Department of Plant Breeding and Biometry paper no. 758     

The influence of artificial photoperiod on the growth,appetite and reproductive status of male red deer and sheep

Young male red deer and Suffolk X (Finn X Dorset) sheep were kept on an artificial photoperiod such that two cycles of daylength occurred during one calendar year. They were penned separately, fed to appetite, weighed weekly and measured tri-weekly.Both species showed two cycles of intake, growth and gonadal activity in response to the daylength when only one would have been shown on natural photoperiod, although in the sheep these cycles were of lower amplitude than in the deer. The deer grew two sets of antlers during the study. A lag of some 3–4 months occurred between an event such as peak food intake and the time it would have been expected to occur relative to the daylength cycle. It is considered that although daylength controls these cycles, there is an endogenous rhythm which photoperiod cannot completely suppress.     

Non-structural carbohydrate partitioning in grass stems: a target to increase yield stability, stress tolerance, and biofuel production

A dramatic change in agricultural crops is needed in order to keep pace with the demands of an increasing human population, exponential need for renewable fuels, and uncertain climatic changes. Grasses make up the vast majority of agricultural commodities. How these grasses capture, transport, and store carbohydrates underpins all aspects of crop productivity. Sink-source dynamics within the plant direct how much, where, and when carbohydrates are allocated, as well as determine the harvestable tissue. Carbohydrate partitioning can limit the yield capacity of these plants, thus offering a potential target for crop improvement. Grasses have the ability to buffer this sink-source interaction by transiently storing carbohydrates in stem tissue when production from the source is greater than whole-plant demand. These reserves improve yield stability in grain crops by providing an alternative source when photosynthetic capacity is reduced during the later phases of grain filling, or during periods of environmental and biotic stresses. Domesticated grasses such as sugarcane and sweet sorghum have undergone selection for high accumulation of stem carbohydrates, which serve as the primary sources of sugars for human and animal consumption, as well as ethanol production for fuel. With the enormous expectations placed on agricultural production in the near future, research into carbohydrate partitioning in grasses is essential for maintaining and increasing yields in grass crops. This review highlights the current knowledge of non-structural carbohydrate dynamics in grass stems and discusses the impacts of stem reserves in essential agronomic grasses.     

Below-ground carbon and nitrogen accumulation in perennial grasses: A comparison of caespitose and rhizomatous growth forms

An experiment was conducted to compare below-ground soil organic carbon and total nitrogen accumulation between caespitose and rhizomatous perennial grasses in long-term (<25 yrs) grazed and ungrazed sites in semi-arid and mesic communities in the North American Great Plains. Development of greater nutrient pools beneath than between clones occurred at minimal clone basal areas (<60 cm²) for both caespitose species. Caespitose grasses accumulated substantially greater pools of carbon (20–200 fold) and nitrogen (50–500 fold) in soils to a depth of 10 cm beneath clones than rhizomatous grasses accumulated in rhizomes in both communities. Carbon and nitrogen pools in soils beneath caespitose clones exceeded combined (soil + rhizome) pools for rhizomatous grasses for a majority of the clone basal areas (>90 cm²) in the mesic community. In contrast, both pool sizes were smaller beneath the caespitose grass at all clone basal areas than the combined pools for the rhizomatous grass in the semi-arid community. The occurrence of larger soil nutrient pools beneath the rhizomatous species in the semi-arid community was largely a consequence of niche separation for microsites characterized by soils with higher nutrient concentrations, rather than plant-induced increases in nutrient concentrations. Although nutrient islands do not occur beneath rhizomatous grasses, their distribution in the semi-arid community was restricted to microsites characterized by soils with higher SOC and N concentrations. A greater efficiency of nutrient accumulation per unit rhizome mass and the maintenance of rhizome nutrient pools of similar magnitude to those of the rhizomatous grass in the mesic community may also contribute to the distribution of rhizomatous grasses in semi-arid communities. The existence of nutrient islands beneath a wide range of clone sizes in both mesic and semi-arid communities provides circumstantial evidence to suggest that nutrient islands beneath caespitose grasses may contribute to clone fitness in this growth form.     

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。     

Biogas production from boreal herbaceous grasses – Specific methane yield and methane yield per hectare

The objective of this study was to determine the specific methane yields of four grass species (cocksfoot, tall fescue, reed canary grass and timothy) cultivated under boreal conditions as well as how harvesting time and year of cultivation affects the specific methane yields per ha. The specific methane yields of all grasses and all harvests varied from 253 to 394 Nl CH₄/kg volatile solids (VS) added. The average specific methane yield of the 1st harvest of all grasses was higher than the 2nd harvests. In this study the methane and energy yields from different harvest years were ranged from 1200 to 3600 Nm³ CH₄/ha/a, corresponding from 12 to 36 MWh_CH4${\text{MWh}}_{{\text{CH}}_4}$/ha/a. The methane yield per hectare of the 1st harvest was always higher than that of the 2nd harvest per hectare because of the higher dry matter yield and specific methane yield. High biomass yield per hectare, good digestibility and regrowth ability after harvesting are important factors when choosing grass species for biogas production. If 30% of fallow and the second harvest of grassland were cultivated grasses and harvested for biogas production in Finland, the energy produced could be 4.9 TWh_CH4${\text{TWh}}_{{\text{CH}}_4}$.