牧草生物技术的研究及实用化前景

牧草是一个包括种类繁多的经济植物类群, 我国丰富的牧草种质资源。建立牧草现代生物技术, 利用牧草生物体的特性与功能, 操作细胞和基因等, 进行牧草的改良和生产, 提供高额和高质量的产品是迫切需要的, 其作用也是常规技术不能代替的。我国在牧草生物技术研究方面已取得了进展, 特别是在一些重要牧草苜蓿等的花药培养、组织培养和细胞培养上初步形成了自己的技术群, 进展尤为显著。而牧草基因工程的研究也已起步。从目前国内外牧草生物技术发展趋势来看, 今后应该首先把细胞工程的研究放到一个重要位置, 明确目标、集中力量、发挥优势, 使这方面的研究有更多的进展, 向实用化方向突进。同时, 也要不失时机地开展基因工程的研究, 建立适合牧草特点的基因工程技术体系, 在短期内应该有较大的突破。     

我国牧草种质资源创新研究进展

本文总结了几十年来我国牧草种质资源创新研究的方法和成果,详细阐述了种内杂交、远缘杂交、射线辐射、离子束注入、太空搭载、化学诱变及基因转化等不同技术方法在牧草种质资源创新中的应用,并对我国牧草种质资源创新的应用前景进行了讨论,以期为促进我国牧草种质资源创新和育种研究的进一步发展提供参考。     

牧草生物技术的研究及实用化前景

牧草是一个包括种类繁多的经济植物类群,我国丰富的牧草种质资源。建立牧草现代生物技术,利用徼草生物体的特性与功能,操作细胞和基因等,进行牧草的改良和生产,提高这种几高质量的迫切需要的,其作用也是常规技术不能代替的。我国在牧草生物技术研究方面已取得了进展,特别是在一些重要牧划苜蓿等的花药培养、组织培养和细胞培养上初步形成了自己的技术群,进展尤为显著。而筵席昌基因工程的研究起步。从目前国内外牧草生物技术     

我国牧草种质资源重要性状分子标记研究进展北大核心CSCD

分子标记技术发展迅猛,正日益成为牧草种质资源的辅助研究手段,其研究技术也日趋成熟。概述分子标记应用在产量、品质、抗逆性和抗病虫等牧草重要性状上的研究进展,分析牧草种质资源重要性状分子标记中存在的问题,并对其应用前景进行展望,以期为今后我国在牧草种质资源方面进一步开展相关研究提供参考。     

优质牧草水分利用效率提高技术研究综述

水资源短缺是干旱半干旱区草地牧草生长的核心限制因子。在有限的水资源基础上,研发提高牧草的水分利用效率和提高牧草生产力的技术,是牧区草业持续稳定发展的关键途径。本文综述了国内外相关进展,系统阐述了提高牧草水分利用效率的灌溉调控、地表覆盖、耕作调控、微生物调控和植物蒸腾抑制等措施和技术;对目前中国北方草地在牧草水分利用效率提高方法研究领域存在的问题、未来需要加强的研究方向进行了分析。未来研究需要从加强抗旱优质牧草品种的筛选和培育、重视牧草水分利用效率田间原位实验和加强抗旱机理与水分利用率提高机制研究、应用先进的研究技术和方法、建立水分高效利用的综合技术体系和复合管理模式等4个方面开展。     

放牧对草地的作用

从牧草生长、种群、群落、土壤和生态系统5个方面分析了放牧的作用、机理与途径。放牧改变牧草的物质与能量分配格局,多途径地诱导牧草的补偿性生长,取决于放牧制度等因素。放牧还改变种间竞争格局、调控种群更新,以及群落结构和功能。介绍了草地健康管理的阈限双因子法,讨论了稳定态一过渡态假说和草地灌丛化。家畜对土壤有直接和间接两种作用途径,作用效果与放牧强度、季节、地形有密切关系,重点分析了放牧对土壤C贮量的作用机制。阐述了提高放牧系统生产力的系统耦合机制,以及放牧对生态系统物质循环的影响。根据放牧生态学的发展趋势和我国放牧管理现状,提出7项值得深入研究的问题。     

禾本科牧草分子生物学及生物技术研究进展

牧草的研究和开发在我国西部生态建设和草地畜牧业发展等方面具有十分重要的意义。禾本科牧草的分子生物学及生物技术研究虽然起步较晚,但在近年取得了令人可喜的进展。以黑麦草属、鸭茅属、羊茅属、赖草属和披碱草属的几种“模式牧草”为重点,从分子标记研究、遗传图谱绘制、基因克隆以及遗传工程等方面对这些研究进展进行了综述。对Genbank中已登录的众多基因进行了信息汇总分析。重点评述了禾本科牧草繁殖方面的分子生物学研究进展。对分子标记、基因工程和比较基因组学应用于禾本科牧草的研究给予了前景展望。     

关于保持盐池草原畜牧业生态平衡的建议

草原生态平衡是草原生态系统结构与功能关系的最优协调。为了保持草原生态系统的相对稳定,我们对宁夏盐池县草原畜牧业提出以下建议,供大家讨论。1.作好草原保护、管理和建设工作,为牧草转化为畜产品创造良好条件草原畜牧业生产过程要完成从牧草生产到畜产品生产的年度生产周期。如果某一环节失调或配合不好,就会直接影响产品获得。天然草场和人工草场是牧草转化为畜产品的基本     

曲江县种草养牛的绿色食品生产环境条件初探

简述了在曲江县的气候条件下的牧草试种情况及适于在该县种植的一些牧草品种．并对曲江县的大气、水、土壤三方面的环境质量及其绿色食品生产标准作了初步的探讨。     

禾本科牧草植物的结构、生长特性及其生理学基础

阐述了禾本科牧草植物形态结构特征,生长特点及其光合生理基础,比较了暖季Ｃ４型牧草和寒季Ｃ３型牧草的差异。对不同发育阶段牧草的田间管理以及提高水分利用效率的途径进行了讨论．     

Adlay or job’s tears—A cereal of potentially greater economic importance

The bony fruits of this grass have for centuries been used in the Orient, ornamentally when polished and as food when ground into flour. The plant is today acquiring importance in Brazil as a fodder and forage crop, and the grain is being used there as poultry and cattle feed.     

Landscape nutritional patterns and cattle distribution in rangeland pastures

On rangelands, uneven or unmanaged livestock distribution can adversely affect plant community composition, riparian function, or displace wildlife. These issues have historic precedents and are still a challenge for those managing rangelands. A thorough understanding of the mechanisms governing livestock distribution can help land and livestock managers avoid or ameliorate many deleterious effects. To that end, this research tested hypotheses that grazing cattle seek nutritionally superior portions of rangeland pastures. Global positioning system (GPS) collars were used to track cattle movement and activity in three, 800+ ha pastures where the spatial distribution of standing crop, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and forage digestibility (in situ dry matter disappearance (ISDMD)) were mapped in late spring. Four of five analyses implied grazing cattle spatially responded to forage quantity/quality attributes. Analyses indicated cattle favored higher than average CP (P = 0.006) and ISDMD (P = 0.078), and lower than average NDF (P = 0.003) and standing crop (P = 0.069) locales. No significant effect (P = 0.954) occurred with ADF analyses. Correlations among those variables imply cattle may simultaneously respond to more than one nutritional attribute as they select foraging locales. Stepwise regression, however, relating grazing distribution to geophysical and forage quantity/quality characteristics were extremely poor predictors of where cattle grazed. Listed in order of entry, the model implied elevation above or below stock water, horizontal distance to stock water, forage CP content, and degree of slope were the site specific attributes most associated with cattle distribution. We speculate that cattle interactions with landscape level nutritional dynamics may at least partially explain seasonal changes in distribution and forage use by cattle across the landscape. These findings should help land and livestock managers understand, explain, and manipulate livestock distribution on their holdings.     

Regional environmental simulation of African cattle herding societies

Regional analyses of the interaction between human populations and natural resources must integrate landscape scale environmental problems. An approach that considers human culture, environmental processes, and resource needs offers an appropriate methodology. With this methodology, we analyze problems of food availability in African cattle-keeping societies. The analysis interrelates cattle biomass, forage availability, milk and blood production, crop yields, gathering, food subsidies, population, and variable precipitation. While an excess of cattle leads to overgrazing, cattle also serve as valuable food storage mechanisms during low rainfall periods. Food subsidies support higher population levels but do not alter drought-induced population fluctuations. Variable precipitation patterns require solutions that stabilize year-to-year food production and also address problems of overpopulation.     

Temporal patterns of crop raiding by elephants: a response to changes in forage quality or crop availability?

Temporal patterns of crop raiding by elephants were studied for 13 months in 1996/1997 at Kibale Forest National Park, Uganda. To determine the influence of environmental factors on the timing of raiding, we tested for correlations between crop raiding patterns and the quality of natural forage within the forest as well as crop availability beyond park boundaries. Crop raiding occurred throughout the year with peaks in dry seasons when crop availability was high. Bananas and maize were the main crops raided. Variations in forage quality were moderate with small seasonal fluctuations and peaks in dry seasons. Monthly crop raiding incidences were not influenced by forage quality but by ripening of maize. Comparison of forage quality and temporal distribution of crop raiding between savanna and forest habitats suggests that crop availability is more important in forest habitats, whereas in savanna habitats large seasonal fluctuations in forage quality have a greater influence on temporal patterns of crop raiding.     

Cattle select African savanna termite mound patches less when sharing habitat with wild herbivores

African savanna termite mounds function as nutrient‐rich foraging hotspots for different herbivore species, but little is known about their effects on the interaction between domestic and wild herbivores. Understanding such effects is important for better management of these herbivore guilds in landscapes where they share habitats. Working in a central Kenyan savanna ecosystem, we compared selection of termite mound patches by cattle between areas cattle accessed exclusively and areas they shared with wild herbivores. Termite mound selection index was significantly lower in the shared areas than in areas cattle accessed exclusively. Furthermore, cattle used termite mounds in proportion to their availability when they were the only herbivores present, but used them less than their availability when they shared foraging areas with wild herbivores. These patterns were associated with reduced herbage cover on termite mounds in the shared foraging areas, partly indicating that cattle and wild herbivores compete for termite mound forage. However, reduced selection of termite mound patches was also reinforced by higher leafiness of Brachiaria lachnantha (the principal cattle diet forage species) off termite mounds in shared than in unshared areas. Taken together, these findings suggest that during wet periods, cattle can overcome competition for termite mounds by taking advantage of wildlife‐mediated increased forage leafiness in the matrix surrounding termite mounds. However, this advantage is likely to dissipate during dry periods when forage conditions deteriorate across the landscape and the importance of termite mounds as nutrient hotspots increases for both cattle and wild herbivores. Therefore, we suggest that those managing for both livestock production and wildlife conservation in such savanna landscapes should adopt grazing strategies that could lessen competition for forage on termite mounds, such as strategically decreasing stock numbers during dry periods.     

Production-based control of parasitic nematodes of cattle

Nematode parasite control in cattle is the goal of the parasitologist and the cattle producer. However, the language used to express the impact of that control has been a source of confusion between the two groups. Veterinary parasitologists speak in terms of reduction in worms or worm eggs, and cattle producers in terms of weight gain, milk production or calving rate. During the development of doramectin for cattle in temperate climates worldwide, the point came when we began to look for a different set of parameters to guide trial design and to communicate the results. In this paper, a series of published papers resulting from the yearling portion of this development programme are reviewed from the viewpoint of weight gain in relation to forage/feed availability. A pattern emerged that indicated that yearling cattle, when parasite control was effective (as indicated by egg counts) and forage was sufficient (as indicated by weather patterns), gained from 0.75 to 0.95 kg day(-1) in trials from the USA, Europe and Argentina. When parasite control or forage supply or both were insufficient, these rates of weight gain were significantly reduced. If more attention is spent on forage availability and weight-gain parameters when parasite-control programmes are designed, then researchers might communicate more meaningful information to producers on the value of parasite control.     

Forage radish and cereal rye cover crop effects on mycorrhizal fungus colonization of maize roots

Forage radish (Raphanus sativus L. var. longipinnatus) is being used by increasing numbers of farmers as a winter cover crop in the Mid-Atlantic USA. It is a non-host to arbuscular mycorrhizal fungi (AMF) and releases anti-fungal isothiocyanates (ITCs) upon decomposition in the winter. Field experiments were conducted to determine the effect of forage radish and cereal rye (Secale cereale L.) cover crops on arbuscular mycorrhizal fungus colonization of and P acquisition by a subsequent maize (Zea mays L.) silage crop. Cover crop treatments included forage radish, rye, a mix of forage radish and rye, and no cover crop. Mycorrhizal fungus colonization of maize roots at the V4 stage following forage radish cover crops was not significantly different from that in the no cover crop treatment. In 3 out of 6 site-years, a rye cover crop increased AMF colonization of V4 stage maize roots compared to no cover crop. These findings suggest that forage radish cover crops do not have a negative effect on AMF colonization of subsequent crops.     

Climate change and cattle nutritional stress

Owing to the complex interactions among climate, plants, cattle grazing, and land management practices, the impacts of climate change on cattle have been hard to predict. Predicting future grassland ecosystem functioning relies on understanding how changes in climate alter the quantity of forage produced, but also forage quality. Plant protein, which is a function of plant nitrogen concentrations, and digestible energy limit the performance of herbivores when in short supply; moreover, deficiencies can be expensive to mitigate. To better understand how changes in temperature and precipitation would affect forage protein and energy availability, we analyzed over 21 000 measurements of cattle fecal chemistry acquired over 14 years in the continental US. Our analysis of patterns in forage quality among ecologically defined regions revealed that increasing temperature and declining precipitation decreased dietary crude protein and digestible organic matter for regions with continental climates. Within regions, quality also declined with increased temperature; however, the effects of precipitation were mixed. Any future increases in precipitation would be unlikely to compensate for the declines in forage quality that accompany projected temperature increases. As a result, cattle are likely to experience greater nutritional stress in the future. If these geographic patterns hold as a proxy for future climates, agriculture will require increased supplemental feeds or the consequence will be a decrease in livestock growth.     

籽粒苋几个品种的光合强度测定

经测定籽粒苋的光合强度显著高于大豆,从美国引进的几个品种的光合强度显著高于国内的品种。成分分析表明籽粒苋含蛋白质丰富,是有潜在开发价值的饲料作物。     

Joint use of habitat by red kangaroos and shorthorn cattle in arid central Australia

The distribution of cattle and red kangaroos among the major communities of a 170 km² paddock in central Australia was determined from 108 and 82 air surveys respectively over a four and a half year period. Fifty-nine surveys of each species were used in this report. Changes in use of the communities by the two species were analysed in relation to forage conditions using linear regression techniques. The two species showed trends in time of use of the open and wooded communities. Kangaroos used the mulga-perennial community (groved Acacia woodland with a shrub and perennial grass understorey) during good forage conditions and moved to the drought refuge open communities when forage conditions deteriorated. Cattle, on the other hand, used the open communities during good forage conditions and tended to move to the mulga communities and the hills when drought began. Mulga-annual (ungroved Acacia woodland with short grass and forb understorey) was the only major community which showed no clear linear relationship between kangaroo use and forage conditions. This might be a buffer area from which kangaroos come and go as other areas become more attractive as feeding areas. Cattle, however, show some preference for mulga annual during medium forage conditions. There appears to be little spatial interaction by the two species except during drought when kangaroos concentrate on the open communities and some cattle continue to feed in these communities. Community selection seems to be determined mainly by forage conditions, as there is no evidence that one species attracts or repels the other in spatial terms. In the conditions observed, the two species successfully coexisted with some control of numbers of cattle by man.