冬小麦茎秆生长过程中内源激素动态的系统研究

以冬小麦为材料,研究了小麦茎秆各节间伸长形成过程中内源激素系统的动态变化。结果表明,茎秆伸长启动期 IAA 含量与节间长度和节位相关密切。节间长度与伸长启动期的 IAA 含量呈极显著正相关(r=0.9353~(**));CTKs 在1,5节间含量较低;2,3,4节间含量较高;伸长过程中,随节间序位的上升,GAs 含量增加百分比大幅度提高;ABA 在整个茎秆伸长过程中含量极低。可见,IAA 与 GAs 互作,共同调控节间的伸长,其中 IAA 可能是决定节间长度的基础,与基因型有关;GAs 在调控节间长度上起主要作用。随节间的伸长和充实,IAA 含量与最大节间单位长度干重成极显著正相关(r=0.9227~(**))。IAA 与CTKs 保持原有的变化趋势,并维持到充实期末,CTKs 在第3节间含量最高,其上位和下位节间则逐步减少,似乎与茎粗有关;ABA 仍维持较低水平。节间单位长度干重达高峰后,贮存物质开始输出(撤退),IAA 和 ABA 含量在生长后期各节间均有较大幅度上升;CTKs 在输出率较高的3,4节间含量较高,而输出率较低的1,5节间含量较低;GAs 含量随节间伸长、充实、物质输出的进程逐渐增加。     

草鱼免疫相关细胞的超微结构的研究

以草鱼血液为样品作超微结构的观察。与哺乳动物相比较,草鱼血液中除红细胞、血栓细胞外,还有免疫相关细胞,包括淋巴细胞、单细胞、酸性白细胞、中性白细胞及巨噬细胞,但没有观察到碱性粒细胞。另发现草鱼淋巴细胞表面有较多突起,巨噬细胞形状不定。     

棉花丰产株型,株高,茎粗与单株成铃的关系

对棉花株高、茎粗与单株成铃性进行了调查研究,所调查群体17．05万株．hm－2;株高平均81．9厘米,茎粗平均0．86厘米．主茎节间长度均匀,单株成铃10．5个。性状分析结果表明,单株成铃与珠高、茎粗相关极显著。由此推断：在保证茎杆粗壮和节间长度均匀的前提下,适当增加棉株高度,对进一步提高产量有利。     

原始生殖细胞的人类胚胎干细胞克隆

取材于妊娠终止胚胎生殖腺或生殖嵴及其周围组织,用ＤＭＥＭ＋ＮＣＳ培养液体外培养,分离由人ＰＧＣｓ转化成的类ＥＳ细胞,并将其与同源胚胎成纤维细胞一起用胰蛋白酶＋ＥＤＴＡ的无钙镁ＰＢＳ液消化传代。在原代培养１２ｈ观察到胞体较大、边缘不整、贴壁分裂增殖的ＰＧＣｓ样细胞,４８ｈ后观察到２６处紧密排列呈鸟巢状的类ＥＳ细胞集落及集落团。第６ｄ传代成功,第１６ｄ传至第４代。结果表明,体外培养附植后胚胎能够建成人的类ＥＳ细胞系。     

细胞永生化的研究进展

永生细胞系具有无限增殖能力,其自我更新能力、增殖分化模式、基因表达调控以及癌症等疾病研究一直以来也是分子细胞生物学领域的研究热点与难点.细胞永生化是指细胞在体外培养的时候,由于自身基因改变或者外界因素刺激,例如细胞周期检查点通路受损、端粒酶的再次激活上调、原癌基因激活等影响,使细胞分裂加快,并突破了自我衰老与凋亡机制,...     

Differentiating A and B groups of Leptosphaeria maculans, causal agent of stem canker (blackleg) of oilseed rape

Stem canker or blackleg of brassicas, caused by Leptosphaeria maculans , is one of the most damaging diseases of winter oilseed rape in the UK. Airborne ascospores, released in autumn and winter, initiate leaf infections which may lead to colonization of the petiole and, later in the season, formation of stem lesions and cankers. Although isolates of the pathogen differ in ability to cause damaging stem cankers, this is not readily apparent from leaf spotting or stem lesion symptoms. However, several cultural, biochemical and genetic characteristics appear to be associated with the ability to form damaging stem cankers and isolates can be assigned to one of two groups, termed A and B, on the basis of differences in these characteristics. To investigate the relationship between leaf spotting symptoms and subsequent stem canker formation, and to improve understanding of the epidemiology of this pathogen, it is desirable to differentiate between the stem canker forming A group and the less damaging B group of L. maculans . Characterization of isolate type is also important in seed testing and crop breeding programs, particularly in countries such as Canada and Poland where the A type is not ubiquitous. This article reviews methods, including plant assays, assessments of growth characteristics in vitro , isozyme analyses, secondary metabolite profiling, serology, and nucleic acid analyses, that can be used to differentiate the A and B groups.     

Interactions Between French Isolates of Phomopsis/Diaporthe Helianthi Munt.-Cvet. et al. and Sunflower (Helianthus annuus L.) Genotypes

Three artificial infection tests measuring the rate of mycelial growth of 7 Phomopsis/Diaporthe helianthi isolates were used on leaves, stems and capitula of 6 sunflower hybrids. Isolates and hybrids were chosen to cover the range of variability and resistance levels known at the present time. Significant genotype and isolate effects and isolate×genotype interactions were shown in all the tests, with some changes in order of hybrids according to the isolate used for infection. Consequences of interactions in breeding for stable resistance to P./D. helianthi are discussed.     

凋亡素基因真核表达载体的构建及在人肿瘤细胞中的表达

为探讨凋亡素对肿瘤的基因治疗效果,构建了凋亡素基因的真核表达载体。将凋亡素基因重组入 ｐｃ Ｄ Ｎ Ａ３ 载体,并通过脂质体介导凋亡素在人喉癌、人肺癌细胞系中表达;通过 Ｒ Ｔ Ｐ Ｃ Ｒ 在转染细胞中检测到了凋亡素的 ｍ Ｒ Ｎ Ａ,这为应用凋亡素进行肿瘤的基因治疗奠定了基础。     

小鼠孤雌胚的体内体外发育研究

小鼠孤雌激活卵登攀上培养于ＣＺＢ溶液中可发育至孵出囊胚阶段,而且孤雌胚移植后可在受体子宫内附植发育。单倍体、二倍体孤雌胚发育至桑椹胚的能力相似,但发育于囊胚的能力,后得高于前者。孤雌囊胚体外发育至孵出的比率仅为２０％,但在卵巢切除的受体子宫内期发育至孵出囊胚的比率提高到７３．３％。与受精扩张囊胚相比,孤雌扩张囊肿成纤维细胞饲养层上很难贴壁生长,但延迟孤雌囊胚的内细胞团（ＩＣＭ）呆在细胞饲养层上增殖     

A Load Cell Based Yield Monitor for Peanut Feasibility Study

A prototype peanut yield monitoring system based on load cell transducers was evaluated for use in precision farming applications. Noise characteristics under simulated field conditions were examined, and the effect of mixing within the peanut combine during harvest was also investigated. Evaluation results showed that the system has potential for providing limited quality site-specific yield measurements for yield mapping applications.