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组织学生通过研究废旧电池的浸提液对绿豆、萝卜种子萌发的影响,通过无土栽培法研究废旧电池的浸提液对芫荽幼苗生长的影响,结果表明:废旧电池的浸提液对绿豆、萝卜种子的发芽率、胚根有抑制作用,对芫荽幼苗生长也有抑制作用. 相似文献
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高中生物学教材在“植物的矿质营养”、初中生物学教材在“植物生长需要哪些无机盐”的章节里,都安排了无土栽培的实践活动。所谓无土栽培,就是指不用土壤,而是采用营养液和其他栽培设施,对植物进行的一种特殊培养。由于无土栽培耗时长、难度大、技术要求高,教材上安排的这些实践活动在许多学校就形同虚设。笔者经过几年栽培试验,将无土栽培根据植物营养液和栽培设施的不同划分为三种形式：即普通无土栽培、简易无土栽培和最简无土栽培。三种栽培方式由繁到简、由难到易,分别适合高中、初中、小学不同层次的学生选用。 相似文献
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《河南职业技术师范学院学报(职业教育版)》2017,(5)
以入侵植物酢浆草(Oxalis corniculata L.)和红花酢浆草(O.corymbosa DC.)为供体,常见蔬菜模式种萝卜为受体,探究两种酢浆草茎叶在浸提温度分别为5、15、25、35℃及浸提液质量浓度分别为0.04、0.06、0.08、0.10 g/mL时对萝卜种子萌发率和幼苗生长的影响.结果表明:酢浆草和红花酢浆草均对萝卜种子的萌发率和幼苗根长产生了极显著的抑制作用(P0.01),且对根长的抑制作用大于对种子萌发率的抑制作用.当两种酢浆草浸提液质量浓度达到0.06 g/mL时,各浸提温度下的种子萌发率与对照组相比均已呈现极显著差异(P0.01),而质量浓度为0.04 g/mL的两种酢浆草浸提液对幼苗根长的抑制作用已达到极显著水平(P0.01).在相同质量浓度下,随着浸提温度的升高,两种酢浆草浸提液对萝卜种子萌发率和幼苗根长的抑制作用均呈现增强趋势;在相同浸提温度下,随着浸提液质量浓度的升高,两种酢浆草浸提液对萝卜种子萌发率和幼苗根长的抑制作用也均呈增强趋势. 相似文献
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深液流无土栽培（DFT）营养液管理技术 总被引：1，自引：0，他引：1
营养液是无土栽培的关键,以黄瓜深液流无土栽培营养液为研究对象,根据实际测得的营养液温度,溶解氧和电导率,观察其试验数据判断对黄瓜生长的影响,并对其进行合理调控和管理,使其在特定时期维持在一定的范围之内,协调好它们之间的相互关系和相互影响,让黄瓜更好地正常快速生长。这一实践性的技术,将有利于无土栽培技术的提高与发展,为今后研究提供依据和方法。 相似文献
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采用营养液栽培模式比较了几种营养液配方在无土栽培西葫芦过程中营养液性质的变化,结果表明:在栽培过程中营养液的性质有较大变化.无土栽培西葫芦各处理营养液的pH值在一日内均表现出明显的上升趋势,由pH6.5上升至pH7.2以上;营养液的溶解氧显著降低,一日内迅速由6mg/L降至4mg/L以下;营养液的EC值在一个营养周期内表现出明显的降低趋势.营养液的EC值与营养液中NO3-N、P、K的含量呈极显著直线正相关. 相似文献
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对比试验表明,有机生态型无土栽培在保护地番茄栽培中,其产量和品质与较高肥力的土壤相差无几,而高于一般营养液基质栽培;有机生态无土栽培灌溉排除液中硝酸盐含量也远低于一般的营养液基质栽培,对环境影响也大大降低.在施用有机肥料以及配合少量化肥的条件下,其产量和品质都得到明显改善. 相似文献
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为探讨不同温度对桐柏野生大豆种子萌发的影响,将浓硫酸处理(浓硫酸浸泡12 min)的种子分别置于5℃、10℃、15℃、20℃、25℃、30℃的恒温条件下进行发芽测试,每天记录各个温度下种子的发芽情况,共观察记录一周,最后计算不同温度下种子的发芽率、发芽势和发芽指数.试验结果表明,桐柏野生大豆种子的适宜萌发温度为20℃～25℃,萌发过程受温度和时间共同影响. 相似文献
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无土栽培植物的根,长期浸泡在营养液中,管理不当更易造成烂根,从而导致植株死亡。通过实验证明,水中的溶解氧、营养液成份是否均匀、水中生物以及空气湿度和温度等四个方面都会影响无土栽培植物的根生长,要及早做好预防措施,保护好根的生长,才能使无土栽培成功。 相似文献
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采用营养液栽培模式比较了几种营养液配方在无土栽培西葫芦过程中营养液性质的变化，结果表明：在栽培过程中营养液的性质有较大变化。无土栽培西葫芦各处理营养液的pH值在一日内均表现出明显的上升趋势，由pH6．5上升至pH7．2以上；营养液的溶解氧显著降低，一日内迅速由6mg／L降至4mg／L以下；营养液的EC值在一个营养周期内表现出明显的降低趋势。营养液的EC值与营养液中NO3^--N、P、K的含量呈极显著直线正相关。 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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《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
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献