共查询到20条相似文献，搜索用时 62 毫秒
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目的:通过采用无菌土培培养方法,阐明外源高铵态氮施用量与水稻幼苗生长、土壤吸附态氨基酸吸收之间的关系。创新点:借助无菌培养和~(15)N同位素示踪方法,揭示高铵态氮浓度条件下土壤吸附态氨基酸对水稻幼苗生长发育及其氮营养贡献的影响。方法:采集两种不同生态系统的土壤A和B,经0.5 mol/L K_2SO_4连续淋洗5次,121℃灭菌30 min,~(15)N-甘氨酸处理后,根据甘氨酸吸附曲线(图1)确定甘氨酸吸附饱和点和吸附半饱和点,然后向土壤中添加一些不同浓度的铵态氮,水稻幼苗无菌培养21天后,用MAT-271质谱仪测定水稻幼苗氨基酸吸收量。结论:实验结果表明土壤甘氨酸吸附能力大小与土壤理化性质紧密相关,如有机质和阳离子交换量。外源高铵态氮水平显著抑制水稻幼苗生长发育(P0.05),但甘氨酸吸收及其氮营养贡献与甘氨酸吸附能力大小无关,而与土壤吸附态甘氨酸和铵态氮的浓度比值显著相关(P0.05)。经过21天的无菌培养,土壤吸附态氨基酸对水稻的氮营养贡献率达8.8%~22.6%,表明土壤吸附态氨基酸理论上可能作为植物的一种潜在重要营养氮源。 相似文献
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1.探究某种矿质元素是否为植物的必需元素原理:采用水培法(无土栽培法),不能用土培法和其他基质培养,因为土壤和其他基质含有矿质元素,对实验造成影响.判断一种元素是不是植物的必需元素,要符合二个条件一是缺乏该元素时,植物会出现某种症状,不能正常生长.二是补充该元素后,症状消失,能正常生长.例思:路:为验证“镁是植物生长的必需元素”,下列是某同学设计实验的基本思路:取生长状况一致的大豆幼苗,栽培在盛有砂性土壤的容器中(砂性土壤肥力均匀,容器符合实验要求),对照组浇以含有植物必需的各种元素的完全营养液,实验组浇以不含镁离子的完… 相似文献
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以青稞幼苗为试材,采用营养液水培法研究了200mmol／L NaCl胁迫对青稞幼苗叶片相对含水量（RWC）、叶绿素、丙二醛（MDA）、脯氨酸含量的影响．结果显示,在200mmol／L NaCl胁迫2,4,6,8d后,青稞幼苗叶片相对含水量、叶绿素含量随胁迫的进行而不断下降,其中叶绿素含量在前4d下降尤其明显;MDA和脯氨酸含量则显著上升．表明200mmol／L NaCl胁迫对青稞幼苗造成了严重的生理伤害． 相似文献
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NaCl胁迫对水稻（Oryza sativa）种子萌发和幼苗生长的影响 总被引：1，自引：0，他引：1
采用水培法,研究不同浓度（0、50、100、150、200、250、300、350、400、450、500mmol／L）的NaCl胁迫对水稻种子萌发,胚根、胚芽和幼苗生长的影响。结果表明：种子的发芽势、发芽率、都随着NaCl胁迫浓度的升高而降低,300mmol／L以上种子发芽率为0;胚根长,胚芽长也随着NaCl胁迫浓度的升高而降低,浓度大于100mmol／L时有显著（p〈0．05）影响。水稻幼苗的根长、株高、株鲜重、根干重以及茎干重也随NaCl胁迫浓度的升高呈逐渐降低的趋势,当浓度大于250mmol／L时影响尤为显著,大于300mmol／L时,植株严重失水,萎蔫,枯黄,死亡。研究结果说明NaCl胁迫对水稻种子的萌发和幼苗的生长有严重的抑制作用。 相似文献
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分别利用0、0.0001、0.001、0.01、0.1、1.0、10、100 mg/L浓度的萘乙酸（NAA）溶液对两系杂交水稻＂开优8号＂的种子进行消毒后浸种处理。通过在智能光照培养箱中培养、观察,研究了不同浓度的NAA浸种对＂开优8号＂幼苗生理特性的影响。结果表明,0.0001～0.01mg/L NAA溶液浸种能促进水稻幼苗的生长,提高水稻幼苗中的叶绿素、POD和CAT含量,提高水稻幼苗的抗逆性,其中最佳浓度为0.001mg/L,而0.1～100mg/L NAA溶液却抑制幼苗生长,降低叶绿素、POD和CAT含量。 相似文献
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以玉米幼苗的生物量、叶片的可溶性糖、可溶性蛋白、丙二醛（MDA）含量、过氧化物酶（POD）与过氧化氢酶（CAT）活性为指标,采用水培法研究了不同浓度抗坏血酸（AsA）对渍涝胁迫下玉米幼苗生长的影响．结果表明：经0.3 mmol/L AsA缓解后受迫玉米幼苗的根长、株高、鲜重和干重明显增加,叶片的可溶性糖与可溶性蛋白含量均明显提高,叶片的CAT与POD活性均高于对照组和各处理组,且叶片的MDA含量显著降低． 相似文献
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岳桦 《中国科教创新导刊》1999,(2)
日本环境工业实验室有限公司开发出一种促进幼苗生长的电子系统,该系统使土壤成份电离,直接活化植物种子的胚乳,促进植物对水和营养成分的吸收。该电子系统向耕种土壤直接相连,通过维持土壤的电势差改良土壤的性质（土壤改良及PH值调向中性）,提高土壤及营养成分的活性,同时提高植物的生物活性及生长（离子化促进了植物对营养物的消化和吸收入土壤溶液及植物细胞内部溶液中的生物离子的电离使得营养成分更易溶解,并调节可能不够大的土壤电势差,从而提高植物的生物活性。阳离子受正极排斥移向负极,而阴离子受负极排斥移向正极,以… 相似文献
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植物生理学实验教学中,无时不用到种子、幼苗及植物各器官。实验材料的选择和生长情况与实验成功、实验质量、实验结果都有很大关系,该文总结了作者多年来在植物生理学实验中实验材料的选择与培养方面的实验教学经验。 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献