Freezing Stress Influences Emergence of Germinated Perennial Grass Seeds

In sagebrush rangelands perennial bunchgrasses are typically seeded in fall and a high proportion of planted seeds germinate prior to winter onset but fail to emerge in spring. Our objectives were to evaluate freezing tolerance of germinated but nonemergent bluebunch wheatgrass seeds under laboratory conditions. We used data from a 2-yr pilot study to determine overwinter freezing temperature and duration for soils in southeastern Oregon. We then conducted two experiments to assess freezing tolerance. In experiment 1, bluebunch wheatgrass seeds were planted in control pots and compared to seeds planted at early, mid, or late postgermination stages. Pots from each treatment were placed in a grow room maintained at 12 h 40 min light/11 h 20 min dark photoperiod, with a constant temperature of 22°C for 30 d either immediately or following a 30-d freeze. In experiment 2, germinated bluebunch wheatgrass seeds were planted in pots that were left nonfrozen or were frozen for a specified duration prior to a 30-d period in the grow room. Emergence density and tillers · seedling^?1 were quantified for both experiments. The number of days per year for freezing soil conditions in the pilot study ranged yearly from 25 to 51; maximum duration of continuous freezing was 16.5 and 11.2 d. Freezing reduced or eliminated seedling emergence at all postgermination stages (P < 0.001) and tiller density was reduced by at least 50% (P < 0.001). Maximum reduction in seedling density (P < 0.001) was realized within 4 d of initiation of freezing and tillers · seedling^?1 were reduced 30–70% with > 6 d of freezing (P = 0.001). Our data indicate that freezing-associated mortality of germinated but nonemergent bluebunch wheatgrass seedlings can be extremely high and suggest that management practices to reduce prewinter germination of seeds could improve subsequent emergence and seeding success.     

四种多年生禾本科牧草引种试验

为选择适于本地区栽培的高产、优质多年生禾本科牧草,于2014年至2015年在同仁县年都乎乡进行不同多年生禾草的引种试验。结果表明,四种多年生禾草都能适应本地区,但相比之下,在平均草层高度和产量方面多叶老芒麦明显高出其它三种牧草,更适宜在该地区大量种植,可以作为人工草地建设和天然草场改良的优良牧草。     

Increasing Shrub Use by Livestock in a World with Less Grass

Much of the world's rangeland is dominated by woody species. Competing land uses and continued encroachment of woody species into non–woody-dominated rangelands have reduced grasslands in many parts of the world. Land use conversions to fuel and feed global populations, especially the increasing number of middle class people seeking broader, meat-based diets, will certainly continue. Halting and/or reversing further encroachment of woody species into grasslands is slow, expensive, and in some cases not possible. Yet, global livestock numbers continue to increase to meet the growing demand for red meat and other livestock products. How do we reconcile a world with less grass and the concurrent increased demand for forages to feed livestock? Strategies and mechanisms are needed to safely enhance shrub use by ruminants in order to capitalize on a presently underutilized forage resource. A number of approaches are presently available (e.g., choosing appropriate species and breeds, providing dietary supplements and additives, behavior modification, genetic selection) to increase shrub consumption, and new technologies such as biochemical markers of shrub intake need to continue to be identified and developed. Such strategies could provide important means for rural communities to adapt to changing land cover and climate.     

刚察县22种多年生禾草引种试验报告

1999－2001年对22种国内外牧草及野生驯化牧草的物候期进行了田间观察，通过牧草的越冬率、鲜草产量、种子产量、千粒重等综合因素进行分析，认为在青海省刚察县最适宜种植的牧草是本地牧草品种。     

果洛地区多年生牧草引种试验初报

在果洛地区两个试验点同时进行２５种牧草的引种试验和室内发芽试验。结果表明：１１种禾草和２种豆科牧草表现良好，６种禾草和１种豆科牧草一般，３种禾草和１种豆科牧草农现差。     

高丹草与黑麦草适宜混贮比例研究

为研究高丹草(Sorghumbicolor×Sorghumsudanense)与黑麦草(Lolium perenne L.)适宜的混合青贮比例,本试验将不同比例[10:0(A),7:3(B),5:5(C),3:7(D),0:10(E)]的高丹草与黑麦草进行混合青贮,室温条件厌氧发酵60 d后测定了青贮的营养成分、发酵品...     

提高多年生人工草地建植当年产草量的研究

研究结果表明,在高寒牧区建植多年生人工草地,适当混播燕麦不仅可显著提高播种当年的产草量,而且对提高前两年产草总量亦有效果。在老芒麦与燕麦的混播组合中,以老芒麦每公顷用种量３０ｋｇ、燕麦每公顷用种量７５ｋｇ,可形成较合理的群体结构。     

Biomass Not Linked to Perennial Grass Mortality Following Severe Wildfire in the Southern High Plains

In March 2006 the East Amarillo Complex (EAC) wildfires burned over 367 000 ha of short and mixed grass prairie of the southern High Plains, USA. We studied EAC wildfire effects on perennial grass mortality and peak standing crop on Deep Hardland and Mixedland Slopes ecological sites. Deep Hardlands were dominated by blue grama (Bouteloua gracilis H.B.K. [Griffiths]) and buffalograss (Buchloe dactyloides [Nutt.] Engelm.); common species on Mixedland Slopes were little bluestem (Schizachyrium scoparium [Michx.] Nash.) and sideoats grama (Bouteloua curtipendula [Michx.] Torr.) with scattered sand sagebrush (Artemisia filifolia Torr.) sometimes present. We hypothesized that perennial grass mortality would increase and standing crop would decrease following severe wildfire, and that these responses would be greater than documented prescribed fire effects. Frequency of perennial grass mortality was higher on both sites in burned areas than nonburned areas through three growing seasons following wildfire; however, standing crop was minimally affected. Results suggest that post-wildfire management to ameliorate wildfire effects is not necessary, and that wildfire effects in this area of the southern High Plains are similar to prescribed fire effects.     

三种预处理方法对多年生王草的酶解产糖效果研究

以高产多年生牧草王草为材料,比较常温稀碱法、微波辅助稀碱法、超声辅助稀碱法三种预处理方法对王草的酶解产糖效果的影响。结果表明:常温稀碱法处理的条件为NaOH浓度3%(w/v),固液比1∶15(w/v),处理时间36h,王草的酶解还原糖产量是406.98mg/g,超声辅助法糖产量最高可比常温稀碱法提高24.65%,微波辅助法最高可提高17.95%。最优的预处理方法为超声辅助稀碱法1,还原糖产量为507.31mg/g。     

石羊河流域浅山干旱区牧草引种试验

为选择适合石羊河流域干旱地区种植的牧草,对9个多年生禾本科牧草进行了物候期、产草量和适应性研究。结果表明：老芒麦、肥披碱草、垂穗披碱草、冰草和西伯利亚冰草在产草量和适应性方面表现较好,适宜在该地区推广种植,可以作为退耕还草、建立人工草地的优质牧草。     

高寒牧区初建多年生禾草人工草地杂草群落特性的研究

对高寒牧区人工多年生禾草草地建植第一年杂草群落特性进行的研究结果表明 ,该区禾草人工草地杂草种类组成较为简单 (13种均为阔叶杂草 ) ,但危害很大 ,其中灰绿藜、萼果香薷、微孔草等不但生长旺盛 ,与禾草共生同期生长 ,且密度和盖度大 ,频度高 ,为该草地群落的优势杂草种。通过计算SDR4 值 ,该人工草地群落为 :灰绿藜 -萼果香薷 -禾草 ,即杂草为主的群落 ,故必须进行杂草的防除 ,否则人工草地建植失败。此外 ,通过分析还提出了杂草防除建议     

祁连山区建植二年不同人工草地杂草群落特性的研究

对祁连山区人工多年生不同禾草草地建植第二年杂草群落特性进行的研究结果表明,该区禾草人工草地杂草种类组成较为复杂(26种均为阔叶杂草),但危害不大,只是其中细叶亚菊生长旺盛,与禾草共生,同期生长,频度较高,密度、盖度较小。通过计算SDR4值知该草地杂草入侵不严重。     

农杆菌介导多年生黑麦草遗传转化体系的建立

AVP1基因能够提高植物的抗盐性,通过农杆菌介导AVP1基因转化多年生黑麦草,并建立了较为成熟的遗传转化体系。研究表明,将预培养4d的黑麦草胚性愈伤组织经OD600为0.6左右的农杆菌菌液在负压下侵染6min,共培养3d,用250mg/L的羧苄青霉素(Carb)脱菌,附加150μmol/L的乙酰丁香酮(AS),然后转接到含75mg/L潮霉素(Hpt)的筛选培养基上进行筛选培养的转化体系效果最佳。     

Immature Seedling Growth of Two North American Native Perennial Bunchgrasses and the Invasive Grass Bromus tectorum

Pseudoroegneria spicata (Pursh) A. Löve and Elymus wawawaiensis J. Carlson & Barkworth are two native perennial grasses widely used for restoration in the Intermountain West. However, the rapid establishment and spread of Bromus tectorum L., an invasive annual grass, has led to a decline in the abundance of native perennial grasses. Proliferation of B. tectorum has been attributed to its early germination, superior cold-temperature growth, profuse root production, and high specific leaf area (SLA). To enhance restoration success, we compared B. tectorum to commercially available plant materials of two perennial rangeland bunchgrasses, P. spicata (cv. Whitmar, cv. Goldar, and Anatone Germplasm) and E. wawawaiensis (cv. Secar), for germination, seedling morphological traits, and growth rates at the immature seedling stage. We monitored germination and immature seedling growth in a growth chamber in two separate experiments, one under low (5/10°C) and the other under high (15/20°C) day/night temperatures. Compared to the average of the two perennials, B. tectorum was 93% (77%) greater at high (and low) temperature for root∶shoot length ratio, but only 14% (14%) greater for root∶shoot biomass ratio and 12% (19%) lower for SLA. This suggests that B. tectorum’s substantial investment in surface area of roots, rather than in shoot length, root biomass, or leaf area, may be responsible for the annual’s success at the early seedling stage. Compared to E. wawawaiensis, P. spicata averaged 65% (41%) higher shoot biomass, 39% (88%) higher root biomass, and 70% (10%) higher absolute growth rate, but 25% (15%) lower SLA and 15% (36%) lower specific root length (SRL) at high (and low) temperatures, respectively. Although P. spicata’s greater productivity may initially make for better seedling establishment than E. wawawaiensis, it may also prove disadvantageous in competitive or highly resource-limited environments where high SLA or SRL could be an advantage.     

多年生人工草地建植技术及其在石漠化治理中的应用

多年生牧草品种的混播对于人工草地建植及其可持续利用研究具有重大意义。本研究分析了多年生人工草地的国内外发展及研究现状,探讨在石漠化地区进行人工草地建植的前景及应用策略。提出在石漠化治理中人工草地的建植应根据区域布局、水热条件、人工草地类型、人工草地与家畜饲养带耦合、草地与耕地功能置换等方面来进行,并以此提高石漠化地区人工草地的生产力并维持其持久力和稳定性。     

不同光强对4种草坪草类胡萝卜素的影响

为明确不同光照强度对不同遗传背景的草种体内的色素比值的影响,设33%,66%,100%正常光强3个光强梯度处理沿阶草(Othiopogon japanicus)、高羊茅(Festuca arundinacea Shreb.cv.ruby)、崂峪苔草(Carex giraldiana)和紫羊茅(Festuca vubra L.cv.boreal)草坪草,采用高效液相色谱仪和Waters Spherisorb ODS-2 columns封口色谱柱,测定各草种色素的相对含量,并比较叶绿素a/b(Chla/Chlb)、黄体素/叶黄素库(L/V)、α-胡萝卜素及其衍生物/β-胡萝卜素及其衍生物(αC/βC)和类胡萝卜素/叶绿素(Car/Chl)。结果表明:随着光照强度的减弱,4种植物体内的Chla/Chlb比值在逐渐减少,αC/βC比值反而增加,Chla/Chlb,L/V,Car/Chl在4草种间差异不显著,αC/βC比值在不同遮荫强度下各草种间差异显著(P<0.05),沿阶草的比值最低,紫羊茅的最高,因此可将α-胡萝卜素及其衍生物/β-胡萝卜素及其衍生物的比值作为植物耐荫性的指标。     

高寒地区微肥对多年生人工草地生产性能的影响

在5a中华羊茅（Festuca china）和冷地早熟禾（Poa alpigena）人工草地上，进行不同微量元素肥料配比的追肥试验。试验结果表明：（1）在中华羊茅和冷地早熟禾处理组中，进行的硼砂、硫酸铜和硫酸锌的追肥处理，对牧草的地上生物量和种子产量有提高作用。在中华羊茅草地里，硼肥处理分别提高地上生物量和种子产量为12．2％和10．2％；在冷地早熟禾草地里分别提高13．2％和10．2％，差异均显著；但Cu肥、Zn肥处理组间的差异不显著；（2）硼肥对中华羊茅和冷地早熟禾两种植株的分蘖密度和有效小穗数影响显著，分别提高12．3％、9．3％、10．5％和8．8％；铜肥和锌肥效果的差异不显著。     

高寒地区微肥对多年生人工草地生产性能的影响

在5a中华羊茅(Festuca china)和冷地早熟禾(Poa alpigena)人工草地上,进行不同微量元素肥料配比的追肥试验。试验结果表明:(1)在中华羊茅和冷地早熟禾处理组中,进行的硼砂、硫酸铜和硫酸锌的追肥处理,对牧草的地上生物量和种子产量有提高作用。在中华羊茅草地里,硼肥处理分别提高地上生物量和种子产量为12.2%和10.2%;在冷地早熟禾草地里分别提高13.2%和10.2%,差异均显著;但Cu肥、Zn肥处理组间的差异不显著;(2)硼肥对中华羊茅和冷地早熟禾两种植株的分蘖密度和有效小穗数影响显著,分别提高12.3%、9.3%、10.5%和8.8%;铜肥和锌肥效果的差异不显著。     

黄土高原人工灌草系统不同立地条件土壤种子库特征

本研究通过野外调查取样与室内试验相结合,连续两年对黄土高原人工灌草系统不同坡向、坡位进行取样,以期对该区土壤种子库的物种组成、密度特征及其物种多样性进行初步了解。研究结果表明：该人工灌草生态系统土壤种子库共有9科,15种,其组成因坡位、坡向以及年份而异;坡向、坡位均显著影响土壤种子库物种多样性指数、丰富度指数与土壤种子库密度（P<0.05）,土壤种子库密度为3 218～5 492粒·m^-2,总体呈现为阴坡显著高于阳坡（P<0.05）,下坡位显著高于上坡位（P<0.05）;坡位和坡向均对物种均匀性系数无显著影响;年份对土壤种子库无显著影响。上述研究可为黄土高原人工灌草系统的可持续利用与恢复提供参考依据。     

草鱼呼肠孤病毒抗原捕获ELISA检测方法的建立

研究以纯化的羊抗草鱼呼肠孤病毒多克隆抗体作为捕获抗体,抗草鱼呼肠孤病毒的单克隆抗体为检测抗体,建立草鱼呼肠孤病毒抗原捕获ELISA检测方法,其最佳反应条件是：羊多克隆抗体包埋浓度为2.5μg/mL,抗草鱼呼肠孤病毒单克隆抗体工作浓度为1:400稀释,以3％牛血清白蛋白作为封闭液。该方法的检测限为5×105 pfu/mL,且能够特异性检出发病草鱼内脏组织中的草鱼呼肠孤病毒。特异性试验结果表明该方法具有较高的特异性,与病毒性出血性败血症病毒、传染性造血器官坏死病毒和鲤春血症病毒等水产动物病毒株均不反应。该方法还具有较好的稳定性。