集雨限灌对旱作马铃薯产量及水分利用效率的影响

在大田条件下研究了集雨有限补偿灌溉对旱区马铃薯产量及水分利用效率的影响。结果表明,补灌能显著提高旱作马铃薯的产量、水分利用效率和经济系数。与对照相比,补灌处理产量增幅在3.99%~21.21%之间,苗期补灌产量高于薯块膨大期补灌,苗期补灌45 mm具有超补偿效应,补灌90 mm具有高补偿效应。低定额补灌有利于水分利用效率和灌水利用效率的提高,且苗期补灌高于薯块膨大期补灌。补灌明显降低了薯块小薯率而提高了大薯率和中薯率,另外单株薯重也提高了,单株薯重与大薯率对马铃薯的产量贡献最大。综合分析认为苗期补灌45 mm和90 mm是最优补灌方案和备选方案。     

Sensitivity of four Yeasts to Fungicides and CO2 Concentrations and Their Antagonistic Ability in Combination with Fungicide to pathogenic Fungi in vitro

The yeasts Cryptococcus laurentii,Trichosporon pullulans,Rhodotorula glutinis and Trichosporon sp.were used to investigate their sensitivity to four fungicides and different concentrations of CO2,as well as their antagonistic ability to Penicilliumexpansum and Alternaria alternata in vitro when applied with fungicide.There were significant differences in sensitivity to the fungicides among the different yeasts(P = 0.05).R.glutinis was more sensitive to Deccocil,Iprodione and Stroby as compared to other yeasts.Combination antagonistic yeasts with fungicide could more significantly enhance biocontrol ability of the yeasts against the pathogenic fungi in vitro(P = 0.05).C.laurentii was the most effective antagonist among the four yeasts and could completely control spore germination of P.expansum and A.alternata when combined with Stroby at the concentration of 100 μL L-1.The yeasts,except R.glutinis,could grow well on nutrient yeast dextrose agar (NYDA) after 8 d incubation even at 20% CO2 concentration at 25℃.Particularly Trichosporon sp.showeda better adaptability to low temperature as compared to other antagonists.     

免疫抑制剂作用机理的研究进展

20世纪以来,科技工作者对硫唑嘌呤、咪唑立宾、环孢素等免疫抑制剂的作用机理进行了大量研究,本文综述了近年来用于临床或处于临床试验阶段的免疫抑制药物的作用机理研究进展.     

中国上市公司多元化经营绩效的实证分析

通过随机抽样,计算我国57家上市公司1998年-2002年的平均盈利指标和风险指标,根据各公司多元化熵值的大小对样本总体进行分组,分析多元化程度对企业绩效的影响.研究发现1.多元化程度越高,公司的平均净资产收益率越高;2.多元化经营降低了公司收益率的波动水平;3.资产规模越小的公司越倾向于选择多元化经营.     

鸡传染性贫血病毒VP1、VP2基因在杆状病毒表达系统中的表达

将鸡传染性贫血病毒M9905株VP1、VP2基因分别或同时克隆到杆状病毒转移载体pFastBacDUAL中，然后转化到DHIOBAC感受态细胞中与Bacmid杆状病毒穿梭载体进行转座重组，最后将重组子转染Sf9昆虫细胞，得到分别或同时含VP1、VP2基因的重组杆状病毒rBacVP1、rBacVP2及rBacVP1—2。PCR扩增结果证实VP1、VP2基因重组到杆状病毒基因组中；SDS-PAGE电泳分析和间接免疫荧光试验结果表明VP1、VP2基因在重组病毒中得到了表达。     

安哥拉山羊与建昌黑山羊及其杂种后代的DNA指纹分析

以 (CA/GATA/TCC) 5探针 ,HinfI酶切 ,研究安哥拉山羊和建昌黑山羊及安哥拉山羊与建昌黑山羊级进杂交的F2 、F3的DNA指纹图谱。结果 ,在供试山羊中 ,个体平均检出 1 8.2± 0 .4条谱带 ,安哥拉山羊、F2 、F3的鉴别机率分别为 1 .38× 1 0 - 12 ,1 .1 8× 1 0 - 13,0 .50× 1 0 - 10 ;群体内相似系数安哥拉山羊为0 .4 539,F2 为 0 .4 0 77,F3为 0 .61 1 1 ;亲子鉴定的父权概率W =0 .9889;安哥拉山羊与建昌黑山羊比较 ,2 .3kb和 8.6kb谱带为安哥拉山羊的特异谱带     

荒川库蠓人工繁殖的研究

实验室人工模拟条件下成功地进行荒川库蠓的饲养和繁殖。荒川库蠓吸鸡血的饱血时间为10min，饱血率为88.46%，饱血库蠓饲养3d后产卵，产卵率为69.56%。产卵后第2天开始孵化，一般在24h内孵化结束，孵化率为76.75%。幼虫先后蜕皮3次，共分4龄幼虫，1-4龄幼虫的体长分别为：0.3-1.12mm,1.12-3.02mm,3.02-4.55mm和4.55-5.90mm，其幼虫期分别为7、4、4和5d。4龄幼虫化蛹2-3d后即羽化为成蠓，羽化为81.82%,不同温度条件对卵到成蠓的发育影响较大，26℃是荒川库蠓发育相对适宜的温度条件。     

红叶石楠组培苗移栽管理技术

通过组培的方法，可以提高红叶石楠的繁殖系数，而将组增苗移栽到大田必须有一个渐进的适应过程。采用蛭石（6）、珍珠岩（3）、泥炭（1）混合基质作移栽过渡苗床，注意保持环境清洁，控制合理的水分、光照、温度，可以达到较高成活率，苗床过渡40d可移入大田栽培。     

玉米雄性不育突变体mi-ms-3的遗传分析及分子鉴定

Maize is one of the best crops in the utilization of heterosis. Male sterile lines are important germplasms for the hybrids production. A male sterile mutant named mi-ms-3 was obtained by screening in a mutator insertion library. The number of male anthers in tassel decreased and not exserted. There were few anthers with only two pollen sacs in the mutant tassels, and some of the anthers were degenerated to membranous and formed filaments at their ends. Although pollens in the anthers could be stained by I₂-KI, pollen shedding was abnormal and the number of pollen grains decreased. The number of silks in the ear of the mutant increased, and there was a sterile grain on both sides of the maturated kernel. Fertility of F₁ plants, which were obtained by hybridization between mi-ms-3 and maize inbred Mo17, was normal. Genetic analysis of F₂ population showed that the mutant phenotype was controlled by a recessive gene. The candidate gene was preliminarily mapped on the long arm of chromosome 3 by BSA and it was located between a SSR marker and an Indel marker with a distance of 1.5 cM. There are 21 candidate genes in this region. It was finally found that the insertion mutation of Mu transposon occurred at 30 bp upstream of the coding region of zm00001d042618 (zmm16) by transponson tagging and sequencing analysis. The results showed that mi-ms-3 was a new allele of sts1, which caused by a single base mutation in the coding region. RT-PCR analysis indicated that the expression of zmm16 in the mutant was decreased. The identification of the new allelic mutant of sts1 in this study would provide new materials for the study of flower development and hybrid seed production.     

Correlation between myocardial interstitial collagen remodeling and changes in hemodynamics in rats with myocardial infarction

AIM: To study the relationship between cardiac extracellular matrix remodeling and cardiac function after myocardial infarction. METHODS: We observed sequential changes in collagen contents and collagen Ⅰ/Ⅲ ratios in infarct zone (IZ) and non-infarct zone (NIZ) and their relationship to the parameters of left ventricular systolic and diastolic function in the rat model of myocardial infarction induced by ligation of left main coronary artery. RESULTS: Collagen conteants in IZ and NIZ after 3d of myocardial infarction were significantly higher than those in sham group at corresponding time (P<0.05, P<0.01). Collagen Ⅰ/Ⅲ ratio in IZ decreased on day 3, significantly increased after 7 d (P<0.01). Collagen Ⅰ/Ⅲ ratio in NIZ increased significantly afte14 d. Correlated analysis between collagen contents in IZ or NIZ and collagen type Ⅰ/Ⅲ ratio and maximal ascending velocity (+p'_max) or maximal descending velocity of the left ventricular pressure (-p'_max) was performed and the negative correlation between collagen contents in NIZ and +P'_max (r=-0.589, P>0.05) and -P'_max (r=-0.788, P<0.01) was found. Collagen content in IZ positively correlated to the +P'_max (r=0.70, P<0.50), but not to -P'_max (r=-0.29, P>0.05). Collagen type Ⅰ/Ⅲ ratios in NIZ correlated negatively to the +P'_max (r=-0.504, P>0.05) and -P'_max (r=-0.545, P>0.05), but there were no relationship between collagen type Ⅰ/Ⅲ ratios in IZ and +P'_max or -P'_max in IZ. CONCLUSION: Collagen deposition in IZ after myocardial infarction was of benefit to improvement of systolic function. Collagen deposition in NIZ was harmful to systolic and diastolic function.