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1.
全球气候变化对沈阳地区春玉米生长的可能影响   总被引:11,自引:0,他引:11  
利用玉米(Zea mays L.)生长生理生态学模拟模型(MPESM),分别模拟了未来气候变化的12种气候条件下(CO2浓度倍增,平均气温上升1.5℃、3.0℃和4.5℃,降水量增加20%、减少20%、减少40%和降水量不变),沈阳地区土壤湿度、玉米发育和玉米生长的变化,并与当前条件下进行了比较,以评价玉米生长对各气候因子变化的敏感性和全球气候变化下沈阳地区春玉米的生长趋势。研究表明:土壤湿度对降  相似文献   

2.
李明云 《生态学报》1995,15(4):378-384
本文根据11a来中国对虾越冬亲虾生产性培育试验资料的统计分析结果得出:亲虾性腺发育的起点温度为7.9±0.3℃,性腺发育成熟的有效积温为250.4±33.6日度,预测性腺发育成熟所需日期公式为。升高或降低越冬期间的基础水温可控制亲虾产卵时间迟早。产卵期间间歇升降温或连续升温,可控制亲虾集中产卵的次数和亲虾产卵持续时间。亲虾越冬期间,有利于提高亲虾存活率的水温,宜控制在8.0-13.0℃,不宜超过13.5℃,升降温幅度不宜超过1.5℃,以1.0℃左右为好。亲虾产卵期间,有利于亲虾存活率、产后卵子孵化率和亲虾再次产卵率的适宜水温为12.0-15.0℃,不宜超过16.0℃,升降温幅度不宜超过1.0℃,以1.0℃以下为好。  相似文献   

3.
大蒜分生组织培养脱病毒和快速繁殖技术   总被引:9,自引:1,他引:9  
采用茎尖分生组织培养技术,获得了大蒜(Allium sativum L.)的无病毒试管苗。通过基本培养基和激素配比试验,筛选出最佳的培养基组成,进行脱病毒苗的快速繁殖。结果表明:诱导愈伤组织的最适培养基为:MS+BA0.2mg/L+NAA0.5mg/L,月生长率达12.70倍;诱导丛生芽的最适培养基为:B5+BA0.5mg/L+IAA0.2mg/L,丛生芽繁殖系数高达25.5倍,技术上达到了快速繁  相似文献   

4.
大叶紫花苜蓿愈伤组织原生质体再生植株   总被引:15,自引:0,他引:15  
大叶紫花苜蓿下胚轴诱导的愈伤组织在继代培养基上生长快速,易于分散。继代第12d的愈伤组织原生质体的得率为6.5×107/g鲜重。原生质体培养基为SH基本培养基,含有1.0mg/L2,4-0、0.5mg/LBA、2.0g/LCH、2%蔗糖、6%葡萄糖、5mmol/LMES,培养密度为1.0×105/mL。培养至第12d时的原生质体再生细胞植板率为3.7%。由原生质体形成的小愈伤组织在含2.0mg/L2,4-D的MS固体培养基上大量增殖。增殖的愈伤组织转移至2.0mg/L2-ip+0.1mg/LNAA的B5培养基上,形成体细胞胚并发育成完整植株。  相似文献   

5.
研究了香荚兰组织培养中植物激素、椰乳、糖分以及光和温度对器官形成的影响。结果表明,1.5mg/LBA或0.2mg/LBA附加12.5%椰乳或1mg/LNAA有利于芽的增殖和长高;诱导生根用0.5mg/LIAA和3%蔗糖。适宜光照强度80001x、温度28℃,光照以18小时为好。  相似文献   

6.
反胶束萃取血红蛋白的研究   总被引:2,自引:0,他引:2  
张亦飞  韩冬冰 《生物技术》1998,8(1):14-17,6
研究了CTAB-正辛醇-正庚烷交束溶液萃取牛血红蛋白(pHb)时、pH值、表面活性剂浓度、助表面活性剂浓度、离子种类和离子强度、溶剂比以及蛋白质浓度等因素对萃取效果的影响,并以蛋白质分子与表面活性剂分子间的相互作用以及反胶束大空间阻碍作用上进行了解释。研究表明,水相PH值在10.5 ̄12.5之间,KC1浓度为0.1mol/l,反胶束溶液中表面活性剂浓度为0.02mol/l,正辛醇与正庚烷之比为0.  相似文献   

7.
兔2—细胞胚胎电融合及其融合胚体外发育的研究   总被引:6,自引:0,他引:6  
刘林  安民 《遗传学报》1993,20(6):493-498
本文对兔2-细胞胚胎卵裂球电融合制作四倍体胚胎的适宜条件进行了研究。电场强度为2.0千伏/厘米,脉冲时程为40微秒时,可获得最好的融合率(68.9-100%,平均为77.3%)及融合胚发育率(74.5%),该发育率与受精卵体外囊胚发育率(79.3%)相似。对于电融合及融合胚发育,非电解质溶液(0.3mol/L甘露醇+0.1mmol/L氯化钙+0.1mmol/L硫酸镁)优于电解质溶液。融合后,72.  相似文献   

8.
从超数排卵的14只母兔获得438枚受精卵,卵龄16~22小时.显微操作在带微分干涉和相差的Nikon倒置显微镜下进行.注射针的尖端外也0.5μm,离尖端40和80μm处的外径分别为4.2和6.5μm.注射用外源基因是绵羊生长激素基因与MT-1启动基因藕连的线状DNA溶液(1ng/μl).140枚注射的受精卵和未注射的145枚受精卵(对照),在Ham’sF—10培养液(补充生长因子)中培养(38℃,5%的CO2).结果,培养48小时后,注射组卵裂发育率分别是:未卵裂7.9%(11/140)、卵裂至2~4细胞期11.0%(16/140)、卵裂至8~16细胞期80.7%(113/140).对照组相应的卵裂率分别是4.1%(6/145)、12.4%(18/145)和83.4%(121/145).两组卵裂发育率相近.本实验的显微操作对注射后卵的发育没有产生明显的伤害影响.  相似文献   

9.
广西龙虎山猕猴种群生态特征   总被引:4,自引:1,他引:4  
王骏  冯敏 《兽类学报》1996,16(4):264-271
1988~1995年,采用定点观察法和绝对计数与相对计数结合法对龙虎山猕猴种群生态作了调查研究。1990年核心区有猕猴14群,500只左右,猴群密度1.6群/km2,种群密度55.6只/km2.猴群大小平均33.8±23.1(n=6)只。一般每隔4~5年分群一次,猴群群体年均增长率14.8%,种群年均增长率为9.7%。猴群中成年猴性比为7.6±6.5(n=12),1~3岁组的性比为0.74±0.61(n=4),群内未成年猴比例为67.7±3.1%(n=12)。发情交配期最早11月12日,最晚次年1月20日,高峰期12月上旬,持续3个月.产仔期最早4月1日,最晚8月14日,高峰期5月上旬,持续时间4个半月.繁殖率45.5%~100%,平均75.4±13.2%(n=21)。新生猴死亡率较低,新生猴性比(雌:雄)平均0.74±0.34(n=5)。  相似文献   

10.
苎麻疫霉雄器侧生性状的遗传研究   总被引:3,自引:1,他引:2  
高智谋  郑小波 《菌物系统》1999,18(3):270-278
在来自江苏、江西棉花、苎麻和构树的12个苎麻疫霉菌株中均观察到侧生雄器,其比率为4.0-16.5%,在以菌JS-5和PM-8(雄器侧生比率分别为16.5%和9.5%)为亲本所建立的连续2-3代单游动孢子无性一代中,雄器侧生性状可以遗传,但单孢株间雄器侧手比率有一定差异,其分布范围分别为9.0-34.0%和2.5-15.5%,进一步诱导菌株JS-5的单游动孢子株的卵孢子萌发,分别对具侧生雄器和具围生  相似文献   

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It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.  相似文献   

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16.
Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

17.
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

18.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细  相似文献   

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For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.  相似文献   

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