木聚糖酶高产菌株的筛选及其产酶规律研究

本研究采用透明圈比较法,从质粒转化变异菌种资源中纯化出1个木聚糖酶高产菌株。同时,采用单因子和多因子相结合的方法及DNS法,对该菌株的适宜发酵条件和产酶规律及木聚糖酶活检测体系进行了初步研究。结果表明:该菌株在改良培养基中的对数生长期在1～7h之间,产酶高峰期在8h左右,发酵液酶活达到344U/ml;木聚糖酶活力检测采用0.1mol.L-1柠檬酸-柠檬酸钠缓冲液,pH值5.2～5.8,木聚糖浓度0.8%,温度60℃,DNS用量为2.0～2.5m l。     

木聚糖酶高产菌株的筛选及其产酶规律研究

本研究采用透明圈比较法，从质粒转化变异菌种资源中纯化出1个木聚糖酶高产菌株。同时，采用单因子和多因子相结合的方法及DNS法，对该菌株的适宜发酵条件和产酶规律及木聚糖酶活检测体系进行了初步研究。结果表明：该菌株在改良培养基中的对数生长期在1-7h之间，产酶高峰期在8h左右，发酵液酶活达到344U／ml；木聚糖酶活力检测采用0．1mol·L^-1柠檬酸-柠檬酸钠缓冲液，pH值5．2—5．8，木聚糖浓度0．8％，温度60℃，DNS用量为2．0—2．5ml。     

高产纳豆激酶突变菌株产酶条件的研究

为了获得最佳产酶条件,通过研究不同碳源(葡萄糖、木糖、麦芽糖、蔗糖、淀粉),氮源(牛肉膏、蛋白胨、大豆蛋白胨、酵母膏、硫酸铵),碳氮浓度比和无机离子组成的培养基发酵,利用纤维蛋白平板法测定纳豆激酶的活性.得到纳豆激酶的最佳产酶条件为:1.5%蛋白胨,1.5%麦芽糖,0.05%硫酸镁,0.2%氯化钙,0.2%磷酸二氢钠和0.1%磷酸氢二钠;碳氮浓度比为1:1.     

产多酚氧化酶茶树内生真菌的筛选及产酶条件优化

以愈创木酚、α-萘酚、没食子酸、L-酪氨酸和单宁酸等5种酚类物质为底物,采用鉴别培养基筛选法从14株茶树内生真菌中初筛获得4株产多酚氧化酶的真菌。根据变色圈的大小、颜色深浅和摇瓶发酵的结果复筛获得产多酚氧化酶能力较强的菌株CSN-13。对菌株CSN-13产酶营养条件进行初步分析,结果表明,在供试的6种碳源物质中,以麸皮对菌株CSN-13产多酚氧化酶的促进作用最为明显;供试的5种氮源物质中,以硝酸铵的促进作用最为明显;在发酵培养基中添加茶水,对产酶有明显的促进作用。采用正交设计对CSN-13产酶发酵培养基进行初步优化,优化后的培养基配方为：麸皮（40βg·L^-1）、硝酸铵（15βg·L^-1）、茶水（4βg·L^-1）、KH₂PO₄（2βg·L^-1）、MgSO₄·7H₂O（0.5βg·L^-1）、无水CaCl₂（0.075βg·L^-1）、CuSO₄·5H₂O（0.01βg·L^-1）。采用优化后的培养基,菌株CSN-13在28℃下培养5βd,酶活力达到241βU·mL^-1·min^-1,比优化前提高8.5倍。茶树内生真菌菌株CSN-13及其发酵产酶培养基的研究为多酚氧化酶的进一步开发打下了基础。     

纳豆激酶高产菌株的筛选及发酵条件的优化

纳豆是日本的传统发酵食品，对人体有抗癌、延缓衰老等保健作用。从纳豆中提取出的纳豆激酶具有很强的溶解血栓的能力。本文针对我国酱豆和日本纳豆中筛选出的高活力菌株进行比较，筛选出活力最高的菌株，并确定了最优的发酵条件。     

甘蔗根际土壤产木聚糖酶菌株的筛选及鉴定

以木聚糖为唯一碳源,从甘蔗根际土壤中筛选木聚糖酶产量较高的菌株。根据筛选培养基上水解圈的大小和摇瓶培养后木聚糖酶的酶活力筛选到产酶量高的菌株Xw2,其水解圈与菌落的直径比为2.3及初筛酶活力达113.8205 IU.mL-1。并利用形态学及基于核糖体DNA ITS序列构建进化树分析鉴定Xw2菌株为一株木霉。     

红树林土壤中高产纤维素酶菌株的筛选

红树林生态系统复杂,土壤微生物资源丰富。试验采用唯一碳源平板法,从红树林土壤中筛选得172个菌株,分别进行产内切葡聚糖酶、外切葡聚糖酶和β-葡萄糖苷酶的平板鉴定,对较高活力的菌株进行了发酵试验,利用DNS和FPA法测定酶活,获得10株具有高产纤维素酶活性的菌株,其中一株真菌HBZ003分解纤维素能力较强且酶活稳定,其CMC酶活为3 229.67 U,滤纸酶活为1 536.80 U;另一株真菌Z005具有较明显的外切酶阳性特征,其CMC酶活为1 970 U,滤纸酶活为871.67 U,对菌株HBZ003、Z005分别进行形态观察、生化鉴定系统的鉴定,初步确认菌株HBZ003为产紫青霉(Penicillium purpurogenun),菌株Z005为枝状芽枝霉(Cladosporium cladosporioides)。     

诱导大豆抗阿特拉津青霉snef960菌株摇瓶发酵条件的筛选

从实验室保存菌种中筛选出一株具有诱导大豆抗阿特拉津的青霉菌株snef960.利用正交试验优化了发酵培养基组分,其最佳碳氮比为葡萄糖(4%)、硝酸铵(0.6%),发酵培养基中4种无机盐的最佳配比为:氯化钾(0.04%)、磷酸氢二钾(0.15%)、硫酸镁(0.04%)、硫酸亚铁(0.001%).通过单因素试验确定青霉sne...     

豆豉中5株产纤溶酶菌的筛选与鉴定

采用酪蛋白平板初筛的方法,从全国14种纳豆和豆豉中分离到39株具有蛋白酶活力的菌株;又以猪血粉平板进行复筛,并采用纤维蛋白平板法测定纤溶酶活力,得到5株产纤溶酶能力较强菌株,分别命名为CQDC-03、CWND-03、NCDC-02、YJND-01和FJDC-02。对其进行16S r DNA序列分析,结果表明:CWND-03、CQDC-03和Bacillus subtilis相似性为99%,NCDC-02和Bacillus subtilis相似性为98%。因而CQDC-02、CWND-03和NCDC-02认定为Bacillus subtilis,YJND-01和FJDC-02是否为Bacillus subtilis的新种还有待进一步鉴定,但确定其为Bacillus属。     

102份不同来源花生种质对北方根结线虫抗性的田间鉴定

为选育抗线虫花生品种,在北方花生根结线虫分布较均匀的自然病田中种植了102份花生种质,收获时对其进行抗性鉴定调查,得到高感材料14份、中感材料76份、中抗材料12份、耐病材料1份,未发现免疫和高抗种质材料;调查发现种间杂种的杂交后代抗性较强,中抗材料较多;自然病田田间观察发现,紫色种皮花生种质的抗性表现较好。     

土壤解磷细菌分离和筛选方法的建立

以有机磷细菌培养基和无机磷细菌培养基为基本培养基,利用液体培养基进行生物富集,然后通过平板稀释法进行分离筛选,共获得107个菌株.结果表明,以有机磷细菌液体培养基为富集培养基,以无机磷细菌固体培养基为筛选培养基,可以有效地从土壤中分离筛选到解磷菌,初步建立起快速有效筛选解磷菌的体系;固体及液体培养条件下解磷能力的测定结果表明,筛选出的解磷菌有较强的解磷能力,进一步验证了此体系的可行性.     

Effects of winter grazing on spring production of lucerne under Mediterranean conditions

The effects of one severe winter‐grazing of lucerne were studied over 3 years in an experiment in the Ebro Valley, Spain. In this region the crop is harvested six to seven times per season and winter grazing is a traditional practice. On average, winter‐grazing reduced the yield at the first harvest in spring by 200 kg dry matter (DM) ha^?1. This limited yield reduction of 0·06 was accompanied by an increase in the proportion of lucerne in the herbage DM from 0·54 to 0·62, a reduction in the proportion of weeds from 0·39 to 0·36, and a reduction in the proportion of dead material from 0·06 to 0·02. The crude protein concentration and the in vitro DM digestibility increased by 20 g kg^?1 DM and 0·03, respectively. The traditional practice, i.e. of grazing lucerne with sheep once in the winter season, results in only a limited reduction in yield in the spring. In addition, the spring crop has a higher nutritive value.     

对引进CIP甘薯实生种子后代鉴定筛选与评价

以本地甘薯实生种子做对照,将引进的国际马铃薯中心(CIP)甘薯实生种子及其后代品系进行萌芽性、生长势、生产力、抗病性、品质等性状的综合鉴定筛选,结果表明,CIP实生种子的出苗率、移栽率及初选、复选、品系比较等各级试验的入选率分别为60.35%、55.97%、6.30%3、2.18%、16.67%,本地实生种子分别为63.38%、48.97%、4.67%、32.20%、25.76%;筛选结果CIP实生种子和本地实生种子差异不显著。从CIP实生种子后代中筛选出了6个优良品系作为育种材料利用。通过引进CIP甘薯实生种子,在国内鉴定筛选,可以丰富国内甘薯种质基因库,提高育种效率。     

高油大豆新品种中黄20(中作983)的选育和提高大豆含油量的育种研究

利用高油大豆和高产大豆进行杂交,专门配制高油组合,同时大量分析了亲本、杂交后代、辐射后代和品系的含油量,早代测产并在高肥水条件下进行多点鉴定。与此同时,在海南岛进行繁育,加快了育种进程。分析了1168份材料的含油量,表明含油量呈常态分布,离中越远样本越少,含油量在18．50％～19．00％的材料最多,占13．20％。育成的新品种中黄20(中作983)含油量3年平均达23．50％,2002年辽宁、北京和天津品种审定委员会已审定推广,2003年2月经全国品种审定委员会审定推广。此外,我们还育成一大批高油大豆品系,正在参加各地的试验。     

The effect of row spacing on alfalfa seed and forage production under irrigated Mediterranean agricultural conditions

We evaluated the effect of row spacing on seed and forage yields in alfalfa (Medicago sativa L.) using combined seed and forage production plots, in an irrigated Mediterranean agricultural environment. We compared three row distances (20, 40 and 60 cm) in two cultivars at a seed rate of 25 kg ha^?1 over a period of 4 years. We measured the seed yield and yield components as well as forage production. The 4‐year average revealed an overall clean seed yield of 367 kg ha^?1 declining over time, without significant differences in row distances. The number of shoots per square metre differed significantly as a function of row spacing, with averages of 357, 226 and 172 shoots m^?2 for row widths of 20, 40 and 60 cm respectively. The row spacing did not affect the number of racemes per shoot (23·1), the number of pods per raceme (7·2), the number of seeds per pod (6·5) or the thousand seed weight (1·667 g). The average forage production was 20·1, 18·5 and 17·9 Mg DM ha^?1 for row distances of 20, 40 and 60 cm, respectively, with higher yields associated with smaller row distances. Our data demonstrate that row spacing >20 cm does not confer any advantage to the production of alfalfa seed under irrigated Mediterranean agricultural conditions and that close spacing can significantly increase forage yields in the same environment.     

水稻稻瘟病药剂筛选试验总结

通过对不同稻瘟病药剂的筛选试验研究,结果表明:供试药剂对稻瘟病均有一定的防治效果,其中以春雷霉素+咪鲜胺对水稻叶瘟的防治效果较显著,防效为75%;好力克+咪鲜胺对褐变穗的防治效果较好,防效为70%。     

盐胁迫浓度和胁迫时的温度对水稻耐盐性的影响

 在水培条件下，用5种不同浓度的NaCl溶液对20个水稻品种的3~4叶期幼苗进行盐胁迫处理，10 d后考查不同品种单株盐害级别、苗高、茎叶干重和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比等性状。结果表明，0.5%的NaCl胁迫下，品种间的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比差异最大；0.8%的NaCl胁迫下，品种间的相对苗高和相对茎叶干重差异最大。其中韭菜青、农林72、80 85、洞庭晚籼和丁旭稻为强耐盐水稻品种；Pokkali、IR26、小白芒、勐旺谷、明恢63为耐盐或中度耐盐品种。进一步选择8个耐盐性不同的水稻品种，在3种温度条件下进行苗期耐盐性鉴定，发现在相对低温[昼/夜为(23±3)℃/(15±1)℃\]时，水稻生长缓慢，不同品种的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比均较低；在温度较高[昼/夜为(36±1)℃/(26±2)℃\]时，水稻生长加快，不同品种的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比均增高；只有在适温条件[昼/夜为(30±2)℃/(24±2)℃\]下，水稻生长较快，品种间的盐害级别和根系Na[sup]+[/sup]/K[sup]+[/sup]含量比差别最明显。提出在适温条件下，以0.5%或0.8%的NaCl浓度进行水稻品种耐盐性的筛选和耐盐特性的遗传研究比较合适。     

The influence of strain of Holstein-Friesian dairy cow and pasture-based feeding system on grazing behaviour, intake and milk production

A comparative study of grazing behaviour, herbage intake and milk production of three strains of Holstein‐Friesian dairy cow was conducted using three grass‐based feeding systems over two years. The three strains of Holstein‐Friesian cows were: high production North American (HP), high durability North American (HD) and New Zealand (NZ). The three grass‐based feeding systems were: high grass allowance (MP), high concentrate (HC) and high stocking rate (HS). In each year seventy‐two pluriparous cows, divided equally between strains of Holstein‐Friesian and feeding systems were used. Strain of Holstein‐Friesian cow and feeding system had significant effects on grazing behaviour, dry matter (DM) intake and milk production. The NZ strain had the longest grazing time while the HD strain had the shortest. The grazing time of cows in the HC system was shorter than those in both the HS and MP systems. There was a significant strain of Holstein‐Friesian cow by feeding system interaction for DM intake of grass herbage and milk production. The NZ strain had the highest substitution rate with the HP strain having the lowest. Hence, response in milk production to concentrate was much greater with the HP than the NZ strain. Reduction in milk yield as a consequence of a higher stocking rate (MP vs. HS system) was, however, greater for the HP and HD strains compared with the NZ strain. The results suggest that differences in grazing behaviour are important in influencing DM intake and milk production.