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41.
.钱敏之;.傅萼辉;.徐惠珠;.叶银根 《武汉植物学研究》1988,6(3):267-274
本文针对湖北贝母生产中存在繁殖系数低的问题,研究了单鳞片砂培繁殖对提高鳞茎繁殖率的效果和原理。试验结果表明:1.单鳞片繁殖率为对照种鳞茎的5—9倍,2.低温(2—10℃)预处理4—8周和暗条件培养,能有效地提高子球形成率,促使子球迅速长大,3.植物激素(6-BA、KT、2,4-D)处理,有利于促进鳞片不定芽原基的分化,繁殖率为种茎繁殖的9—11倍;4.单鳞片繁殖的小鳞茎主要发生在鳞片基部的茎盘上,还可发生在鳞片的远轴面上,但不发生在近轴面。 相似文献
42.
43.
鼻蝇亚科(Rhiniinae)是双翅目丽蝇科(Calliphoridae)中比较特殊的一大类群,因此也有人把它从丽蝇科分出,独立成科的。其特征有口上片突出如鼻状,后头上部大半是裸出的,约占整个头的宽度的范围内连粉被也缺如;r脉的上方沿后侧有一列明晰的小刚毛,翅下大结节上无立纤毛,下腋瓣裸。主要分布在东洋区、非洲区、大洋洲区以及古北区南缘。目前全世界已知有22个属,近300种,曾有报道其幼虫寄生于白蚁巢内及蝗 相似文献
44.
Culture and characterization of dental follicle cells from rat molars 总被引:12,自引:0,他引:12
Summary Because the dental follicle is necessary for the eruption of teeth of limited eruption, it was the objective of this study to determine if the cells of the follicle could be cultured in vitro. To achieve this, dental follicles and associated enamel organs were dissected from the first and second mandibular molars of 6–7-day-old rats (secretory stage of amelogenesis), and then cultured in a medium that promotes fibroblast growth — the predominant cell type of the dental follicle. The cultured cells grew to confluency and were kept through 3 passages before experimentation. The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained an abundant rough endoplasmic reticulum, but did not form desmosomes. Immunofluorescent staining for anti-vimentin showed that all the cells stained and electron-microscopic immunogold labeling indicated that the antibody was associated with intermediate filaments. As revealed by SDS-polyacrylamide gel electrophoresis and Western blotting, the cultured cells synthesized and secreted the extracellular matrix molecules fibronectin and procollagens. Subsequent immunofluorescence staining of permeabilized and non-permeabilized cells confirmed the presence of fibronectin and type I collagen both intra- and extracellularly. Thus, based on all the above characteristics, the cultured cells appeared to be fibroblasts derived from the dental follicle, although a few of the fibroblasts may be derived from undifferentiated mesenchymal cells interposed between the alveolar bone and follicle. Experiments now can be conducted to determine how these cultured cells respond directly to growth factors that alter the rates of tooth eruption. 相似文献
45.
Dr. Jian Wen Chen Lanping Zhang Jiantao Song Fen Hwang Qinghua Dong Jian Liu Yumin Qian 《Current microbiology》1992,24(4):189-192
The glycoproteins and glycolipids from membranes of virulent strain Z and avirulent strain M ofMycoplasma hyopneumoniae have been compared. The proteins and the glycoproteins were identified by SDS-polyacrylamide gel electrophoresis and concanavalin A-biotin labeling, respectively. The membrane preparation contained approximately 34 protein bands with molecular weights between 20 KD and 100 KD. The concanavalin A-biotin system reacted with a glycoprotein of a molecular weight of approximately 28,000 from avirulent strain M and did not react with the correspondent band from virulent strain Z. The membrane glycolipids of both strains consisted of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), and the percentages of 160, 180, and 181 fatty acids comprised more than 80% of the total fatty acids of membrane glycolipids. The 180 fatty acid of MGDG in avirulent strain M was twofold higher than that of virulent strain Z. 相似文献
46.
鹅掌楸种子和胚胎发育的研究 总被引:23,自引:0,他引:23
应用控制授粉、软 X-射线法、常规石蜡制片法和荧光检测等手段,研究了鹅掌楸(Lirio-dendron chinense(Hemsl.)Sarg.胚胎发育和控制授粉与结籽率的相关性。控制授粉后2小时花粉萌发,6小时萌发率最高,柱头可授期持续30小时左右。花粉管借助于柱头毛之间的分泌物进入柱头沟,经花柱沟、珠孔塞和珠心冠原进入胚囊,行珠孔受精。授粉后2周,胚乳为2至3细胞厚的狭组织;第6周,胚乳充满胚囊腔,珠心随之解体殆尽;第7到8周,球形胚、心形胚发生;第14到16周,子叶形成;第22周种子或熟,胚乳丰富。单株自然授粉结籽率不足1%。控制授粉后,单个聚合果的最高结籽率可达39%,9个聚合果的平均结籽率为17.7%。 相似文献
47.
The retinoblastoma gene product regulates progression through the G1 phase of the cell cycle. 总被引:90,自引:0,他引:90
The RB gene product is a nuclear phosphoprotein that undergoes cell cycle-dependent changes in its phosphorylation status. To test whether RB regulates cell cycle progression, purified RB proteins, either full-length or a truncated form containing the T antigen-binding region, were injected into cells. Injection of either protein early in G1 inhibits progression into S phase. Co-injection of anti-RB antibodies antagonizes this effect. Injection of RB into cells arrested at G1/S or late in G1 has no effect on BrdU incorporation, suggesting that RB does not inhibit DNA synthesis in S phase. These results indicate that RB regulates cell proliferation by restricting cell cycle progression at a specific point in G1 and establish a biological assay for RB activity. Neither co-injection of RB with a T antigen peptide nor injection into cells expressing T antigen prevents cells from progressing into S phase, which supports the hypothesis that T antigen binding has functional consequences for RB. 相似文献
48.
应用毛细管气相色谱标准样品叠加法和色谱-质谱-计算机联用技术分析了巴山冷杉(Abies fargesii Franch. )针叶精油的化学成分。从气相色谱分离出的225个色谱峰中,初步鉴定出43个组分,占精油总量的94.15%,主要成分为α-蒎烯(13.25%)、柠檬烯(10.82%)、石竹烯(10.75%)、莰烯(10.40%)、乙酸龙脑酯(6.9%)、γ-杜松烯(6.28%)、α-蛇麻烯(3.97%)、檀烯(3.52%)、芳萜醇(3.02%)、α-依兰油烯(2.76%)、β-甜没药醇(2.56%)及α-橙花叔醇(2.54%)等。 相似文献
49.
用相关和回归处理方法,研究了8条正常狗咽喉部高频喷射通气时,调节驱动压、呼吸比和频率对喷气量、吸入气氧浓度、动脉血气及气道内压的作用。结果显示,驱动压和呼吸此对各观察指标几乎有同等重要的作用,频率的影响很小,喷气量与吸入气氧浓度、动脉血气、气道内压间存在显著的正相关关系。说明调节参数的意义主要在于改变了喷气量。 相似文献
50.