禾本科及豆科牧草对黄土丘陵区台田土壤培肥效果的比较研究

以黄土丘陵区具有代表性的禾本科及豆科牧草无芒雀麦和沙打旺为材料,研究其对川台地土壤腐歼击质含量和组成,有关营养元素及后茬作物产量的不同影响。结果表明,种植禾本科及豆科牧草均能提高土壤中的腐殖质及氮磷营养的水平,其中禾本科牧草效果较豆科牧草更为明显。     

增产菌对朝阳地区豆科牧草增产效果的试验研究

增产菌(YIB)—植物微生态制剂,是植物保健益菌。我们分别用20ml/亩、40ml/亩、60ml/亩拌“公农一号”紫花苜蓿种子,及用5、8g/亩喷施三年生“公农一号”紫花苜蓿和拌沙打旺种子,其结果是对豆科牧草的株高、产草量。有明显地提高,增加了人工草地的经济效益。关于增产菌在豆科牧草方面的应用目前尚未见过报导。     

60种牧草品比试验

我们从国内外引进和当地采集的牧草中选出60种(或品种)牧草同时进行比较试验。其 中禾本科31种,豆科28种,杂类草1种。分别种植在两种不同的土壤类型上(河质粟钙土和河滩草甸土)。试验共重复6次。每次重复的60种牧草随机排列。每种栽5穴,每穴4—5粒种子。在1991年6月5日播种。以后观测其出苗情况、牧草的生长强度(分夏季和秋季二     

培养法与直接法外周血淋巴细胞微核率的比较研究

用⁶⁰Co r线1.0-5.0Gy照射狗,比较照后12小时培养法和直接法外周血淋巴细胞微核率,结果微核率随剂量增加而增加,培养法增加的速度和幅度明显高于直接法,经统计学分析二者存在一定的相关性。     

国外牧草基因组学和转基因技术研究进展

禾本科和豆科牧草在动物生产、水土保持和环境保护中发挥着重要的作用.随着现代生物技术的发展,以优异基因型品种间多次杂交培育的合成品种为主的传统常规育种方法与以基因组学和转基因为核心的分子育种技术相比,挑战和机遇并存.与主要农作物相比,牧草作物基因组学及其转基因研究尚处于发展阶段.目前,牧草基因组学及转基因在以黑麦草属(Lolium)和羊茅属(Festuca)为代表的禾本科牧草及以三叶草(Triflolium)和苜蓿(Medicago)为代表的豆科牧草中已有较多研究,就现代生物技术在国外牧草遗传育种中的方法、应用及最新研究进展进行综述,旨在为我国牧草常规和转基因育种提供方法参考及思路借鉴.     

培养法与直接法外周血淋巴细胞微核率的比较研究

用⁶⁰Co r线1.0-5.0Gy照射狗，比较照后12小时培养法和直接法外周血淋巴细胞微核率，结果微核率随剂量增加而增加，培养法增加的速度和幅度明显高于直接法，经统计学分析二者存在一定的相关性。     

重离子辐照玉米种子引起的基因组DNA变异分析

利用HI-13串列加速器产生的10 Gy、20 Gy、30 Gy和50 Gy ~7Li和~(12)C重离子束对玉米自交系478的干种子进行辐照,并用RAPD分析技术分析其变异情况.结果表明重离子~7Li和~(12)C辐照玉米种子可引起当代基因组DNA水平上的变异,一定范围内变异频率与注入剂量有关,在相同剂量下~7Li离子辐照的诱变率高于~(12)C离子辐照.     

60Co-γ辐射对家蚕生长发育的影响

利用60Co-γ射线对家蚕卵进行照射,辐射剂量在10 Gy~30 Gy之间对蚕的生长发育等一系列变化进行研究。结果表明:随着辐射剂量的增加,家蚕在1小时内的平均孵化率有极显著提高,对照区的平均孵化率为33.2%,而10 Gy、20 Gy和30 Gy区分别达到34.44%、39.67%和51.11%。四龄第2天随机称量50头蚕,对照、10 Gy、20 Gy和30 Gy区每头蚕平均体重分别为1.174 g、1.116 g、0.975 g和0.862 g,体重随剂量增加明显减轻,其中20 Gy和30 Gy区对比对照和10 Gy区均有极显著差异;茧层率在10 Gy和20 Gy辐照区与对照区比较变化不大,即23.37%、23.54%对比24.25%,而30 Gy辐照区显著降低,为21.74%;单蛾产卵数先升高后降低,从对照区的529粒到10 Gy的540粒和30 Gy的392粒,这可能是辐照使蚕生长发育的机制发生了改变,引起膜损伤、破坏蛋白质的结构的原因,并且对蚕的消化功能也产生了影响。综合考虑在家蚕辐射育种方面10 Gy时的照射效果最佳。     

松嫩草地主要豆科牧草的适应性与种植利用研究

通过比较松嫩草地主要豆科牧草种子萌发期耐盐碱性的差异, 苗期出苗情况和病虫害及种植牧草后对土壤化学性质的影响, 对该6种豆科牧草进行综合评价, 并选出适宜在松嫩盐碱化草地种植的豆科牧草。结果表明, 在萌发期, 紫花苜蓿 (Medicago sativa L.)、扁蓿豆 (Medicago ruthenica)、兴安胡枝子 (Lespedeza davurica)、细叶胡枝子 (Lespedeza hedusaroides)和黄花草木樨 (Melilotus officinalis) 5种小粒种子耐盐碱性好于大粒种子广布野豌豆 (Vicia cracca), 尤其是紫花苜蓿 (M. sativa L.), 其发芽率和活力指数在低盐浓度 (≤ 0.4% NaCl)环境中高于对照条件; 苗期小粒种子出苗较快 (3—4 d), 大粒种子广布野豌豆 (V. cracca) 出苗时间较长 (9 d); 细叶胡枝子 (L.edusaroides)、兴安胡枝子 (L. davurica)和黄花草木樨 (M. officinalis)不易遭病虫害, 其余3种易受蚜虫和七星瓢虫危害。种植6种豆科牧草后土壤氮含量都有一定程度的提高, 尤其是兴安胡枝子 (L. davurica); 土壤pH也有了一定程度的降低, 尤其是紫花苜蓿 (M. sativa L.)。综合比较发现松嫩草地6种豆科牧草以种植小粒种子紫花苜蓿 (M. sativa L.)和兴安胡枝子 (L. davurica)牧草为更好。     

碳离子辐照对菘蓝药性品质和分子水平的诱变效应

以野生菘蓝种子为材料,以不同剂量的碳离子(12 C6+)进行辐照处理(辐照剂量分别为30Gy、60Gy、90Gy、120Gy),分析12 C6+辐照对菘蓝种子萌发、幼苗生长、主要药用成分含量及其基因和蛋白质多态性变化的影响,为菘蓝品质育种、分子生物学研究和重离子辐照诱变的应用提供依据。结果显示:(1)12 C6+辐照处理后菘蓝的成苗率和根鲜重均随辐照剂量增加而逐步显著降低,其中30Gy处理对菘蓝生长抑制程度最小,但处理后菘蓝根中的主要药效成分4(3H)喹唑酮和靛玉红的含量增加幅度最大且最高,分别为野生型的2.2倍和2.3倍。(2)SRAP分子标记分析表明,菘蓝基因组的变异度随着辐照强度的增强而增大,其中30Gy处理的突变体与野生型相比有33.59%的多态性变异。(3)SDS-PAGE考马斯亮蓝染色和磷酸化染色分析表明,菘蓝的总蛋白和磷酸化蛋白表达水平均随辐照剂量变化出现了不同程度的改变,但并不与辐照强度呈正相关,说明植物在防御重离子辐照伤害时存在补偿机制。研究发现,30Gy的12 C6+辐照是菘蓝诱变的最佳剂量,能够显著提高其有效成分的含量,为优质菘蓝诱变育种奠定了基础。     

80MeV/u20Ne10+离子对SMMC-7721细胞DNA损伤及细胞周期的影响

从辐照剂量和修复时间两个角度研究了重离子辐照对肿瘤细胞DNA损伤及细胞周期的影响,为重离子治癌的临床应用积累基础数据。不同剂量的80MeV／u^20Ne^10 辐照SMMC—7721细胞样品,利用单细胞凝胶电泳技术(Single Cell Gel Electrophoresis,SCGE)对细胞DNA损伤进行了检测,利用流式细胞技术(Flow Cytometry Methods,FCM)对细胞周期变化进行了分析。80MeV／u^20Ne^10 辐照后4小时内,SMMC—7721细胞的DNA损伤与辐照剂量呈线性关系,在0小时组其线性相关因子r为0．9621,4小时组为0．914;随着修复时间的增加,DNA损伤与辐照剂量不再线性相关,但0．5Gy,1Gy和2Gy三个剂量点的DNA损伤程度极为相近。另外,重离子辐照后SMMC—7721细胞发生S期和G2／M期阻滞现象,其随剂量变化及时间变化的规律不同于X、γ等低LET(Linear Energy Transfer)射线辐照。     

Effects of white clover (Trifolium repens L.) on plant and soil nitrogen and soil organic matter in mixtures with perennial ryegrass (Lolium perenne L.)

To increase our insight into the above- and belowground N flows in grass and grass-clover swards relations between crop and soil parameters were studied in a cutting trial with perennial ryegrass (Lolium perenne) monocultures and ryegrass–white clover (Trifolium repens) mixtures. The effects of clover cultivar on herbage yield, the amount of clover-derived nitrogen, apparent N transfer to companion grass, dynamics of N and organic matter in the soil were estimated.The grass monocultures had very low DM yields (<2.1 t ha^-1) and a low N concentration in the harvested herbage. During 1992–1995 the annual herbage DM yield in the mixtures ranged from 7.0 to 14.3 t ha^-1, the white clover DM yield from 2.4 to 11.2 t ha^-1 and the mean annual clover content in the herbage DM harvested from 34 to 78%. Mixtures with the large-leaved clover cv. Alice yielded significantly more herbage and clover DM and had a higher clover content than mixtures with small/medium-leaved cvs. Gwenda and Retor. Grass cultivar did not consistently affect yield, botanical composition or soil characteristics.The apparent N₂ fixation was very high, ranging from 150 to 545 kg N ha^-1 in the different mixtures. For each tonne of clover DM in the harvested herbage 49 to 63 kg N was harvested, while the apparent N transfer from clover to grass varied between 55 and 113 kg N ha^-1 year^-1.The net N mineralization rate was lower under monocultures than under mixtures. The C mineralization and the amounts of C and N in active soil organic matter fractions were similar for monocultures and mixtures, but the C:N ratio of the active soil organic matter fractions were higher under grass than under mixtures. This explains the lower N mineralization under grass.     

Serum TNFalpha and its receptors in professionals after prolonged exposure to radiation in remote period

The goal of this study was the detection of serum TNFalpha concentration and soluble receptors (sTNFRI and sTNFRII) in PA Mayak professionals in long-term after the prolonged radiation exposure, subject to cumulative dose. TNFalpha, sTNFRI, and sTNFRII concentration were investigated by ELISA in serum of 59 professionals. Cumulative external doses were within 0.21-7.72 Gy. 239Pu body burden was less than 1.48 kBk. Direct significant correlation was detected between TNFalpha concentration and external dose (0.21-3.(00) Gy; r = 0.41, p = 0.009, n = 40). Serum sTNFRI concentration rose significantly with increasing of cumulative dose. Significant increase of persons number with deviations of sTNFRI concentration from standards in groups with dose higher 1.00 Gy under comparison with control was discovered. The correlation was detected between external dose and serum sTNFRI concentration in long-term after radiation exposure (r = 0.36, p < 0.005). Significant positive correlation was detected between sTNFRI, and sTNFRII under increasing of cumulative external dose (r = 0.60, p = 0.0000004).     

微囊藻毒素与饮用水消毒副产物复合诱导草鱼淋巴细胞凋亡

针对饮用水中消毒副产物与微囊藻毒素的低剂量复合污染问题,采用离体细胞培养诱导方法,以草鱼淋巴细胞为暴露受体,研究了MCLR、MCRR两种微囊藻毒素和CHClBr₂、CHCl₂Br两种消毒副产物的单独与联合毒效应.结果表明:4种污染物在试验浓度下暴露2 h即能使草鱼淋巴细胞发生凋亡,且呈显著的剂量-效应关系;1 nmol·L^-1MCLR、MCRR分别和1～100 nmol·L^-1的CHCl₂Br、CHClBr₂的联合作用均表现为相加作用,并且均呈显著的剂量-效应关系.草鱼淋巴细胞凋亡率可作为一种有效的指标来评价微囊藻毒素及消毒副产物复合污染引起的细胞毒性.     

不同灌溉量对内蒙古人工草地主要牧草产量和水分利用效率的影响

人工草地建设是缓解内蒙古地区草地生存压力的必要途径,而水分短缺是该区人工草地建设中牧草生长的主要限制因素,适量的人工补水以实现牧草的高产节水是解决这一问题的关键。以当地主要牧草冰草和紫花苜蓿为研究对象,开展单播和混播条件下不同灌溉量对牧草产量、光合性能和水分利用效率影响的对比试验。研究结果表明:(1)豆禾混播有利于提高冰草和紫花苜蓿的产量;(2)8月初现蕾期是冰草和紫花苜蓿收割的最佳季节,此时牧草产量最高;(3)灌溉量达到田间持水量的45%(包含降雨量在内的单位面积灌溉量在7月初达到903.8 m3/hm2,在8月初达到1812.4 m3/hm2)是牧草高产节水的最佳补水选择;(4)6—8月水分胁迫更有利于提高牧草的长期水分利用效率(long-term water use efficiency,WUEL),开花期后补水对提高牧草WUEL的作用开始显著;(5)在牧草产量最高的8月初水分胁迫更有利于提高牧草的瞬时水分利用效率(instantaneous water use efficiency,WUEI),而在7月初光照强烈、水分蒸发量大时,较多地补水更有利于提高牧草的WUEI。     

Relationship between radiation induced adaptive response in human fibroblasts and changes in chromatin conformation

Chromatin conformation changes in the normal human fibroblasts VH-10 were studied by the method of anomalous viscosity time dependence (AVTD). Gamma-irradiation of cells in a dose range of 0.1–3 Gy caused an increase in maximal viscosity of cell lysates. Conversely, irradiation of cells with low doses of 0.5 or 2 cGy resulted in a decrease in the AVTD peaks with a maximum effect approximately 40 min after irradiation. The same exposure conditions were used to study a possible adaptive effect of low doses, measured by changes in cell survival. A primary dose of 2 cGy caused significant modification of cell response to a challenge dose. Approximately 20% protection to challenge doses of 0.5 Gy (p < 0.003), 2 Gy (p < 0.02) and 2.5 Gy (p < 0.002) was observed. However, the direction of this effect (adaptation or synergism) was found to be dependent on a challenge dose. The combined effect of 2 cGy and 1 Gy was significantly synergistic, while no modification was observed for 1.5 Gy and 3 Gy. A partial correlation was found between the AVTD changes and cell survival when the combined effect of a primary dose of 2 cGy and challenge dose was examined. The dose of 2 cGy alone increased survival by 16% (p < 0.0003). These results suggest that the low-dose induced effects on survival may be related to chromatin reorganization.     

Degradation of fructans by epiphytic and inoculated lactic acid bacteria and by plant enzymes during ensilage of normal and sterile hybrid ryegrass

Degradation of grass fructans by epiphytic or inoculated lactic acid bacteria during ensilage was examined using both normal and sterile hybrid ryegrass. It was clear that even in the absence of bacteria fructan degradation occurred, but at a significantly slower rate than in normal grass which had not been inoculated with lactic acid bacteria. Fructan degradation in sterile herbage suggests that plant fructan hydrolases were partially responsible for this process in all herbages, irrespective of treatment. Inoculation of sterile herbage with a strain of Lactobacillus plantarum known to lack the ability to degrade grass fructans resulted in a slower rate of fructan breakdown than when inoculated with Lactobacillus casei subsp. paracasei , a confirmed fructan degrader. In the later stages of the fermentation of uninoculated normal herbage when water-soluble carbohydrate appeared to be limiting, lactic acid was fermented to acetic acid. However, this fermentation pathway was not observed in either of the inoculated silages. The results suggest that silage inoculant bacteria possessing fructan hydrolase activity may have potential for improving silage fermentation, particularly when late cut, low sugar grass containing a high proportion of fructans is ensiled.     

Effect of plant species on the larvae of gastrointestinal nematodes which parasitise sheep

Faeces containing Trichostrongylus colubriformis and/or Ostertagia circumcincta eggs were used to provide four contaminations in each of 2 years on plots of browntop, Yorkshire fog, ryegrass, tall fescue, lucerne, chicory, cocksfoot, white clover, and prairie grass and in the second year a mixed sward of ryegrass/white clover. Third stage larvae were recovered from faeces and from four strata of herbage, 0–2.5, 2.5–5, 5–7.5 and >7.5 cm above the soil surface at 2, 4, 6, 8, 11, and 14 weeks after faeces were deposited on the swards. Herbage species had a significant (P &lt; 0.0001) effect on the number of larvae recovered. Greatest numbers of larvae, as indicated by ranking analysis, were recovered from Yorkshire fog, ryegrass, and cocksfoot and lowest numbers from white clover and lucerne. The difference between herbages in numbers of larvae recovered was due to the ‘‘development success’’, the ability of larvae to develop to the infective stage and migrate on to herbage, rather than ‘‘survival’’, the rate of population decline once on the herbage. Faecal degradation was most rapid from white clover and browntop, intermediate from tall fescue, lucerne, prairie grass, cocksfoot, and ryegrass, and slowest from Yorkshire fog swards. The numbers of larvae recovered from herbages were related (r² = 0.59, P &lt; 0.05) with the faecal mass remaining. A greater proportion of the total larvae recovered from the herbage was recovered from the bottom stratum of Yorkshire fog and prairie grass than from white clover, with the other herbages intermediate, indicating that larvae had greater difficulty migrating up Yorkshire fog and prairie grass than the other herbage species. In most herbage species, despite more larvae being recovered from the lowest stratum, larval density (L₃/kg herbage DM) was highest in the top stratum. This study has demonstrated that herbage species can have a significant impact on the population dynamics and vertical migration of T. colubriformis and O. circumcincta larvae.     

The effects of allowance and frequency of allocation of deferred herbage, and grass silage feed value, when offered to ewes in mid-gestation on ewe and lamb performance and subsequent herbage yield

The effects of (i) herbage allowance, (ii) frequency of allocation and (iii) grass silage feed value on ewe and lamb performance were studied in mid-gestation ewes. Furthermore, the effects of (i) herbage allowance, (ii) frequency of allocation and (iii) grazing date and their interactions on subsequent herbage yield and feed value were also evaluated. Swards, which had a cut of silage removed on 6 September, received fertiliser nitrogen (34 kg/ha) for extended (deferred) grazing between 6 December and 1 February. Two grass silages differing in feed value were ensiled either precision chopped or in big bales from predominantly perennial ryegrass swards, respectively. In experiment 1, a completely randomised study involving 120 crossbred mid-gestation ewes (Belclare × Scottish Blackface) that had been mated in October was undertaken to evaluate the effects of extended grazed herbage allowance (1.0 and 1.8 kg dry matter (DM)/day), frequency of herbage allocation (daily and twice weekly) and grass silage feed value (low and medium) on ewe and subsequent lamb performance. The six diets were offered from days 63 to 120 of gestation. From day 120 of gestation to parturition all ewes were housed and offered the medium feed value silage ad libitum. All ewes received 19 kg concentrate prior to lambing. Increasing herbage allowance increased forage intake (P < 0.05), lamb birth weight (P < 0.01), weaning weight (P < 0.05) and growth rate from birth to weaning (P < 0.05), decreased herbage utilisation (P < 0.05) and tended to increase ewe condition score at lambing (P = 0.06). Frequency of herbage allocation or grass silage feed value did not alter (P > 0.05) ewe or subsequent lamb performance. In experiment 2, the effect of extended grazed herbage allowance (1.0 and 1.8 kg DM/ewe daily), frequency of allocation (daily and twice weekly) and grazing date (6 to 12 December, 27 December to 3 January and 17 to 23 January) on herbage yield at two harvest dates (27 April and 25 May) was examined in a split plot design study consisting of 72 plots. Delaying grazing date decreased herbage yield (P < 0.01) whilst delaying harvest date increased herbage yield (P < 0.05). Frequency of herbage allocation did not alter (P > 0.05) subsequent herbage yield. It is concluded that for ewes in mid-gestation 1.0 kg of low feed value silage DM had the same feed value, as determined by weaned lamb weight, as 1.3 kg herbage DM allowance. Each 1-day delay in grazing date reduced herbage DM yield by 54.2 kg/ha.     

三江源高寒草地牧草营养时空分布

草地的产草量和牧草品质影响着草地载畜量和草食动物的营养状况、生命活动及生产性能。以三江源及其周边地区的天然草地不同生长期（返青期,盛草期,枯黄期）牧草为对象,分析草地产草量及牧草品质的时空格局。结果显示：从整个区域看,草地生产力、可食牧草产量以及粗蛋白产量(Crude Protein, CP)分布均具有较明显的地域差异性,三者的高值区大多分布在三江源东部及南部的高寒草甸区,三者的低值区主要在三江源中部和西部的草甸及高寒草原区;大部分地区总生产力和可食牧草产量盛草期显著高于枯黄期,枯黄期显著高于返青期。粗蛋白产量在大部分地区呈现出盛草期显著高于返青期和枯黄期,返青期和枯黄期差异不明显,少数地区返青期显著高于盛草期和枯黄期,盛草期显著高于枯黄期（如：可可西里）;CP含量及产量在三江源区空间上的分布,均为南部地区高于北部地区,东部农牧交错区高于西部无人区;所有区域CP含量的返青期为最高,枯黄期为最低,而其他养分含量在不同区域的季节波动并不一致;盛草期牧草CP含量随海拔升高先增加后减小,粗灰分随着海拔升高而显著增加,中性洗涤纤维、酸性洗涤纤维和酸性洗涤木质素含量随着海拔升高呈降低趋势。结论：三江源及周边地区牧草生产力、可食牧草产量以及CP产量较高,可食性较好;三江源多数地区高寒草地牧草营养质量相对较好,牧草在返青期营养价值最高（蛋白高,纤维低）,到盛草期,牧草产量及营养物质输出量达到最高峰,进入枯黄期的牧草营养质量低劣,此时应进行补饲,以提高家畜生产性能。三江源区可利用草地主要集中在东部、南部和东南部,该区牧草品质较高、利用潜力（粗蛋白产量）较大,可适度利用开发。