Effects of 60-day NO₂ fumigation on growth, oxidative stress and antioxidative response in Cinnamomum camphora seedlings     

Zhuo-mei Chen  Ying-xu Chen  Guo-jian Du  Xi-lin Wu  Feng Li 《Journal of Zhejiang University. Science. B》2010,11(3):190-199

Objective:To study the oxidative stress and antioxidative response of Cinnamomum camphora seedlings exposed to nitrogen dioxide (NO2) fumigation.Methods:Measurements were made up of the growth,chlorophyll content,chlorophyll fluorescence,antioxidant system and lipid peroxidation of one-year-old C.camphora seedlings exposed to NO2 (0.1,0.5,and 4 μl/L) fumigation in open top chambers over a period of 60 d.Results:After the first 30 d,0.5 and 4.0 μl/L NO2 showed insignificant effects on the growth of C.camphora seedlings.However,exposure to 0.5 and 4.0 μl/L NO2 for 15 d significantly reduced their chlorophyll content (P0.05),enhanced their malondialdehyde (MDA) content and superoxide dismutase (SOD) activity (P0.05),and also significantly reduced the maximal quantum yield of PSII in the dark [the ratio of variable fluorescence to maximal fluorescence (Fv/Fm)] (P0.05).In the latter 30 d,0.5 μl/L NO2 showed a positive effect on the vitality of the seedlings,which was reflected by a recovery in the ratio of Fv/Fm and chlorophyll content,and obviously enhanced growth,SOD activity,ascorbate (AsA) content and glutathione reductase (GR) activity (P0.05);4.0 μl/L NO2 then showed a negative effect,indicated by significant reductions in chlorophyll content and the ratio of Fv/Fm,and inhibited growth (P0.05).Conclusion:The results suggest adaptation of C.camphora seedlings to 60-d exposure to 0.1 and 0.5 μl/L NO2,but not to 60-d exposure to 4.0 μl/L NO2.C.camphora seedlings may protect themselves from injury by strengthening their antioxidant system in response to NO2-induced oxidative stress.  相似文献   

毕节试验区技术进步与经济发展相关性分析     

王素君 《毕节学院学报》2010,28(5):59-63

以反梯度理论作为理论基础,采用改进的C-D生产函数模型对1988—2008年毕节试验区经济发展研究发现:自试验区成立以来,经济增长主要依靠劳动力数量增加和资金投入的推动,是一种粗放型的经济增长方式,经济效率低下原因之一是较落后的生产技术,它制约了毕节试验区经济较快发展。因此,试验区经济发展初期应该不断开拓市场,在积极引进资金和管理经验同时,应不断加快技术进步,推动试验区经济实现集约型增长。  相似文献   

Effects of dietary supplementation with Clostridium butyricum on the growth performance and humoral immune response in Miichthys miiuy   总被引：2，自引：0，他引：2  

Song ZF  Wu TX  Cai LS  Zhang LJ  Zheng XD 《Journal of Zhejiang University. Science. B》2006,7(7):596-602

The effects of dietary supplementation with Clostridium butyricum on growth performance and humoral immune response in Miichthys miiuy were evaluated. One hundred and fifty Miichthys miiuy weighing approximately 200-260 g were divided into five groups and reared in 15 tanks with closed circuiting culture system. The animals were fed 5 diets： basal diet only （control） or supplemented of the basal diet with C. butyricum at doses of 10^3 （CB1）, 10^5 （CB2）, 10^7 （CB3） or 10^9 （CB4） CFU/g. Compared with the control, the serum phenoloxidase activity was significantly increased by the supplementation （P〈0.05）, acid phosphatases activity was increased significantly （P〈0.05） at the doses of 10^9 CFU/g. Serum lysozyme activity peaked at dose of 10^7 CFU/g and in the skin mucus at dose of 10^9 CFU/g. Immunoglobulin M level in the serum and skin mucus was increased except at dose of 10^3 CFU/g （P〈0.05）. The growth at the dose of 10^9 CFU/g was higher than that of the control （P〈0.05）. It is concluded that supplementation of C. butyricum can mediate the humoral immune responses and improve the growth performance in Miichthys miiuy.  相似文献   

发展逻辑与路径转化:近世长江下游地区经济发展动力的历史分析     

董佳 《科学．经济．社会》2012,30(1):36-41

明清时期长江下游地区通过劳动分工、生产专业化、商品化,依靠不断扩大的商业市场,在“斯密型动力”推动下有效缓解了日益严峻的经济压力,开启了经济转型的进程.通过转变,该地区的经济商品化程度和工业化程度都有明显的提高.然而,这种“斯密型动力”和生产“过密化”愈发展,对产生工业革命的负面影响就愈大、阻碍性就愈强.事实证明,这种早期的农村工业化并不必然导致近代工业化,长江下游地区(乃至全国)也并不存在一个类似于西方工业革命的光明前景.  相似文献   

金牡丹等茶树新品种生长特性试验研究     

罗小梅  邓慧群  邱勇娟  黄婷婷 《大众科技》2012,14(4):185-186,259

对金牡丹等15个乌龙茶品种在广西桂林区试点与黄旦品种进行种植成活率、新梢生育期、发芽密度、生长势等方面的对比鉴定,在同等条件下探索其生长特性,为评定新品种提供科学依据。  相似文献   

English renewed: Visions of English among teachers of 1966     

John Dixon 《English in Education》2009,43(3):241-250

This article examines the way in which curriculum renewal in English teaching in the late 1960s was brought about largely through the democratic process of teacher participation. It describes the role that the newly formed National Association for the Teaching of English (NATE) played in creating the process in conjunction with American colleagues from the National Council of Teachers of English (NCTE) at the 1966 Dartmouth Conference. The author, who participated in this event, describes the values debated at this conference which underpinned reform and which were subsequently tested out and implemented in England by practitioners in schools, supported by NATE local branches. He asks the reader to consider the ways in which this process of reform differs from the ways in which processes of curriculum change are currently structured.  相似文献   

Discussion: With Choices Come Consequences     

Henry Braun 《Educational Measurement》2009,28(4):52-55

The Growth Model Pilot Program (GMPP) was introduced as a response to criticism of the reliance of No Child Left Behind on status‐based indicators. Although incorporating a growth component appears to be a step in the right direction, it adds a level of complexity that brings to the fore new concerns. Three of the four papers in this special issue address different manifestations of a common problem: how choices related to implementation of the GMPP, made on technical or practical grounds, can have substantial consequences for schools and teachers. The fourth paper explicates a different approach to growth modeling. Together these papers add considerably to our understanding of the strengths and weaknesses of growth‐based indicators. In this discussion, I attempt to set these papers in a larger context before providing brief reviews. I conclude by arguing that the nation will be better served if policy makers appreciated the consequences of choices before they crafted legislation and the accompanying regulations.  相似文献   

S形增长模型的参数估计     

陈克波 《咸阳师范学院学报》2002,17(2):4-7

利用Mathematica软件，给出了生物学中某些S型增长模型的参数估计。  相似文献   

小麦不同生育特性品种栽培技术研究     

姚维传 《安徽科技学院学报》2000,(2)

对半冬性、春性、多穗型、大穗型等不同类型的小麦品种进行高产栽培研究。结果表明 ,在本地区半冬性品种和春性品种的适宜播期分别为 1 0月 1 0日左右和 1 0月 2 0日左右 ;半冬性多穗型和大穗型品种的合理密度分别为 1 80万 /hm2 和 2 40万 /hm2 基本苗。提出了各种类型小麦品种在 6 0 0 0kg/hm2 产量水平下冬前及春季的合理群体指标及产量结构  相似文献   

Optimization of callus cultures at Echinacea purpurea L. for the amount of caffeic acid derivatives     

《Electronic Journal of Biotechnology》2021

BackgroundIn order to produce an effective callus in Echinacea purpurea L.; determination of the explant type and growth regulators that best respond to callus induction and the optimization of the culture conditions to increase the amount of caffeic acid derivatives (CADs) in the obtained callus. CADs contents of callus cultures of E. purpurea were evaluated by establishing an effective callus induction system in vitro.ResultsVarious medium containing different growth regulators were tested using leaf, petiole, cotyledon and root as the explants. The best callus development was achieved in MS medium with 1.0 mg l⁻¹ 2,4-D + 2.0 mg l⁻¹ BAP in leaf, 1.0 mg l⁻¹ NAA + 0.5 mg l⁻¹ TDZ in petiole, 2.0 mg l⁻¹ NAA + 1.0 mg l⁻¹ TDZ in cotyledon and 0.5 mg l⁻¹ NAA + 0.5 mg l⁻¹ BAP in roots. Upon optimisation of callus growth, each type of explant was cultured for 4, 6, 8 and 10 weeks in medium for the analyses of caftaric acid, chlorogenic acid, caffeic acid and chicoric acid contents. The highest amounts of caftaric acid (4.11 mg/g) and chicoric acid (57.89 mg/g) were found from petiole explants and chlorogenic acid (8.83 mg/g) from root explants at the end of the 10-week culture time.ConclusionsAs a result of the present study, the production of caffeic acid derivatives was performed by providing the optimization of E. purpurea L. callus cultures. Effective and repeatable protocols established in this study may offer help for further studies investigating the production of caffeic acid derivatives in vitro.How to cite: Tanur Erkoyuncu M, Yorgancilar M. Optimization of callus cultures at Echinacea purpurea L. for the amount of caffeic acid derivatives. Electron J Biotechnol 2021;51. https://doi.org/10.1016/j.ejbt.2021.02.003.  相似文献