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61.
柴达木盆地荒漠土壤蓝藻群落的初步研究   总被引:6,自引:0,他引:6  
本文分析了柴达木盆地东部和中部具有代表性地区的丘陵、戈壁和沙丘的蓝藻种类组成、生物量及主要的土壤化学成分;采用了模糊聚类、系统聚类及多元线性回归等方法分析藻类的群落及其与环境因子的关系。共鉴定出21种蓝藻,其中6种为国内首次报道。研究表明:土壤含磷量、总盐量及与粘性和湿度有关的土壤结构是决定柴达木盆地蓝藻群落组成的重要因素。  相似文献   
62.
Terminal meristems of Pisum sativum (garden pea) transit from vegetative to inflorescence development, and begin producing floral axillary meristems. Determination for inflorescence development was assessed by culturing excised buds and meristems. The first node of floral initiation (NFI) for bud expiants developing in culture and for adventitious shoots forming on cultured meristems was compared with the NFI of intact control buds. When terminal buds having eight leaf primordia were excised from plants of different ages (i.e., number of unfolded leaves) and cultured on 6-benzylaminopurine and kinetin-supplemented medium, the NFI was a function of the age of the source plant. By age 3, all terminal buds were determined for inflorescence development. Determination occurred at least eight nodes before the first axillary flower was initiated. Thus, the axillary meristems contributing to the inflorescence had not formed at the time the bud was explanted. Similar results were obtained for cultured axillary buds. In addition, meristems excised without leaf primordia from axillary buds three nodes above the cotyledons of age-3 plants gave rise to adventitious buds with an NFI of 8.3 ±0.3 nodes. In contrast seed-derived plants had an NFI of 16.5 ±0.2. Thus cells within the meristem were determined for inflorescence development. These findings indicate that determination for inflorescence development in P. sativum is a stable developmental state, separable from determination for flower development, and occurring prior to initiation of the inflorescence at the level of meristems.  相似文献   
63.
Summary In the hepatitis B surface antigen (HBsAg)-producing recombinant yeast culture medium, the supply of Bacto-yeast nitrogen base without amino acids was found to be inadequate due to the lack of the several kinds of vitamins and trace elements. When the culture medium for this recombinant yeast was supplemented with sufficient vitamins and trace elements, its growth, HBsAg production and the stability of plasmid were improved.  相似文献   
64.
黑叶猴和菲氏叶猴颅骨的比较研究   总被引:1,自引:0,他引:1  
  相似文献   
65.
对武汉东湖三个定点观测站和潜江市一深水机井中异养细菌群落的种群组成、对不同基质的反应、菌株和群落的生理特征和活力水平等方面比较研究结果表明:环境差异较小的东湖Ⅰ、Ⅱ、Ⅲ站异养细菌群落间的差异亦较小,具有类似的结构特征和生理活力水平,对特定基质表现了相似的作用模式;地下水中的异养细菌群落在上述几方面均显示了明显的差别。此外,在异养细菌群落结构和功能研究方法上亦是有益的探讨。  相似文献   
66.
神农架拐棍竹林的初步研究   总被引:1,自引:0,他引:1  
拐棍竹(Fargesia spathacea Franch.)是中国特有分布种类,主要分布川、滇、陕、甘等省。是极有开发价值的植物资源,又是大熊猫取食主要竹种之一。本文研究了神农架拐棍竹林的生态生物学特点,客观地估算了其蕴藏量,进行了营养成分分析。现报道如下:  相似文献   
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H H Li  X F Cui    N Arnheim 《Nucleic acids research》1991,19(11):3139-3141
Single-stranded oligonucleotide primers can be efficiently removed after PCR using E.coli exonuclease VII. Even only a few molecules of double stranded PCR product are unaffected by a treatment which eliminates 20 picomoles of primer in the presence of 500 ng of denatured genomic DNA. Exonuclease VII treatment is rapid and could simplify complicated multistep PCR protocols.  相似文献   
70.
Conclusion Anthropologists have too often supported — in their words, in their presences, and in their deeds — the paternalistic claims of rulers suppressing the very cultures they want to study. Much anthropological work legitimates substitution of the language of Beijing for Hakka and Holo, justifies ignoring Taiwanese culture, and subordinates consideration of its specific features to writing about Chinese civilization, just as Taiwanese are economically and politically subordinated to the ethnic minority dictatorship which still rules Taiwan under the fiction of being the government of China. The China that Arthur Wolf and others serve in return for support of their research from what purports to be the Republic of China is an egregious, but unfortunately not unique, example.Stephen O. Murray is with El Instituto Obregón, San Francisco, California. Keelung Hong is with the Cancer Research Institute, University of California, San Francisco.As is normal in anthropology, except for Taiwan, native terms are romanized in the native language (in the first author's recording of the second author's Daidiong idiolect, without indication of the extremely intricate tone differentia), not in the official language of the ethnic oligarchy ruling Taiwan (Beijinghua). Mainland place names are rendered in pinyin. We have followed the convention of treating Chinese and Taiwanese personal names as two words, because books are catalogued with such names. If personal names are considered as two words (an imposition of the hoary dogma that words in Sino-Tibetan languages are monosyllabic), it seems to us that both words should be capitalized. For Taiwanese placenames, we have not separated syllables by dashes or by spaces.  相似文献   
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