首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
RegulationCultureonCytological,BiochemicalandPhysiologicalCharacteristicsofSomaticCarrotEmbryosHUANGMei-juan;(黄美娟),HUANGShao-...  相似文献   

3.
超干种子耐贮藏性的细胞学及生理生化基础   总被引:17,自引:0,他引:17  
种子超干贮藏是近年来种子生物学研究和植物种质资源保存领域的研究热点。本文综述了种子超干贮藏研究的进展 ,包括 :(1)超干种子的细胞和亚细胞结构变化 ;(2 )超干处理对种子水分状态的影响以及与劣变反应速率的关系 ;(3)超干种子中的自由基伤害和有毒物质的积累 ;(4)超干种子中的内源抗氧剂 ;(5 )糖类物质以及两性物质对极度脱水种子细胞的保护。此外 ,还对此领域的研究进行了展望  相似文献   

4.
Three-week-old sugar beet (Beta vulgaris L.) seedlings were grown for an additional four weeks under controlled conditions: in river sand watered with a modified Knop mixture containing one half-fold (0.5N), standard (1N), and or threefold (3N) nitrate amount, at the irradiance of 90 W/m2 PAR, and at the carbon dioxide concentrations of 0.035% (1C treatment) or 0.07% (2C treatment). The increase in the carbon dioxide concentration and in the nitrogen dose resulted in an increase in the leaf area and the leaf and root dry weight per plant. With the increase in the nitrogen dose, morphological indices characterizing leaf growth increased more noticeably in 1C plants than in 2C plants. And vice versa, the effects of increased CO2 concentration were reduced with the increase in the nitrogen dose. Roots responded to the changes in the CO2 and nitrate concentrations otherwise than leaves. At a standard nitrate dose (1N), the contents of proteins and nonstructural carbohydrates (sucrose and starch) in leaves depended little on the CO2 concentration. At a double CO2 concentration, the content of chlorophyll somewhat decreased, and the net photosynthesis rate (P n) calculated per leaf area unit increased. An increase in the nitrogen dose did not affect the leaf carbohydrate content of the 1C and 2C plants except the leaves of the 2C-3N plants, where the carbohydrate content decreased. In 1C and 2C plants, an increase in the nitrogen dose caused an increase in the protein and chlorophyll content. Specific P n values somewhat decreased in 1C-0.5N plants and had hardly any dependence on the nitrate dose in the 2C plants. The carbohydrate content in roots did not depend on the CO2 concentration, and the content was the highest at 0.5N. Characteristic nitrogen dose-independent acclimation of photosynthesis to an increased carbon dioxide concentration, which was postulated previously [1], was not observed in our experiments with sugar beet grown at doubled carbon dioxide concentration.  相似文献   

5.
Non-vernalized scions were grafted onto vernalized stocks in winter rape (Brassica napus L. var. oleifera, cv. Górczański). The grafted plants were subjected to electric current (30 V for 30 s or 6 V for 24 h) and the percentage of flowering scions was recorded. The negative polarity with cathode (−) attached to the scion and anode (+) left close to the roots inhibited greatly the percentage of flowering. The reverse polarity enhanced flowering markedly under short days and only slightly promoted flowering under long days. Attachment of electrodes without passing a current had no effect on flowering. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

6.
亚麻耐盐性愈伤组织的生理生化特性   总被引:4,自引:0,他引:4  
以亚麻(双亚5号)耐盐愈伤组织为材,以同种亚麻普通愈伤组织为对照,分别经含0~250 mmol·L-1 NaC1的培养基培养20 d后,比较含水量、MDA含量、POD酶活、SOD酶活、EST同工酶谱、POD同工酶谱及SOD同工酶谱。结果表明:亚麻耐盐组愈伤组织与对照组愈伤组织在多方面存在明显差异,前者含水量均高于后者;丙二醛含量也高于后者,但变化幅度不大;POD酶活均高于对照组;酯酶同工酶谱不同于对照组,酯酶酶活量均高于对照组;POD同工酶谱比对照组多一条带,且酶活均高于对照组;SOD同工酶谱与对照组一样多,但酶活均高于对照组,且平稳。这为进一步筛选亚麻耐盐突变细胞系奠定了良好的基础。  相似文献   

7.
超大型烟草突变株的生理生化特征和分子生物学鉴定   总被引:4,自引:0,他引:4  
超大型烟草突变株再生植株高度是野生型的2.2倍,叶片数是野生型的3.3倍,呈现晚花发育特征;叶片气孔保卫细胞中叶绿体数是野生型的1.3倍,叶绿素a、b和叶绿素总量均高于野生型,可溶性蛋白质含量是野生型的1.18倍,过氧化物酶、细胞色素氧化酶同工酶电泳图谱上有一定差异;可溶性蛋白SDS-PAGE电泳图谱上比野生型少4条谱带;RAPD结果表明突变体在DNA水平上确实发生了变化,DDRT-PCR结果显示出两者在基因表达上有差异。突变株再生植株可以开花结实,植株高大、叶数多,晚花的特征可以稳定遗传。  相似文献   

8.
T. Luongo  L.Q. Ma 《Plant and Soil》2005,277(1-2):117-126
This research was conducted to understand the mechanisms of arsenic hyperaccumulation in Pteris vittata by comparing the characteristics of arsenic accumulation in Pteris and non-Pteris ferns. Seven Pteris (P.vittata, P. Cretica Rowerii, P. Cretica Parkerii, P. Cretica Albo-lineata, P. Quadriavrita, P. Ensiformis and P. Dentata) and six non-Pteris (Arachnoides simplicor, Didymochlaena truncatula, Dryopteris atrata, Dryopteris erythrosora, Cyrtomium falcatum, and Adiantum hispidulum) ferns were exposed to 0, 1 and 10 mgL−1 arsenic as sodium arsenate for 14-d in hydroponic systems. As a group, the Pteris ferns were more efficient in arsenic accumulation than the non-Pteris ferns, with P. vittata being the most efficient followed by P. cretica. When exposed to 10 mg L−1 As, arsenic concentrations in the fronds and roots of P. vittata were 1748 and 503 mg kg−1. Though not all Pteris ferns were efficient in accumulating arsenic, none of the non-Pteris ferns was an efficient As accumulator (the highest concentration being 452 mg kg−1). The fact that frond arsenic concentrations in the control were highly correlated with those exposed to As (r 2 = 0.76–0.87) may suggest that they may be used as a preliminary tool to screen potential arsenic hyperaccumulators. Our research confirms that the ability of P. vittata to translocate arsenic from the roots to the fronds (73–77% As in the fronds), reduce arsenate to arsenite in the fronds (>50% AsIII in the fronds), and maintain high concentrations of phosphate in the roots (48–53% in the roots) all contributed to its arsenic tolerance and hyperaccumulation.  相似文献   

9.
亚硒酸钠和硒酸钠对小白菜生长生理特性的影响   总被引:9,自引:0,他引:9  
以小白菜品种'秦白2号'为材料,采用盆栽试验研究了不同浓度亚硒酸钠[Se(IV)]和硒酸钠[Se(VI)]胁迫对小白菜生长生理特性的影响及其生理机制,为土壤硒污染修复及其合理开发利用提供理论依据.结果表明,Se(IV)≤10.0 mg·kg-1时,小白菜的叶长、叶宽显著下降,而生物量没有受到显著影响;Se(VI)≤1.0 mg·kg-1时,叶长、叶宽、生物量没有显著变化;更高浓度处理时,叶长、叶宽、生物量均随外源Se(IV)和Se(VI)处理浓度的增大而急速下降.Se(IV)≤40.0 mg·kg-1和Se(VI)≤20.0 mg·kg-1处理均对小白菜叶片叶绿素含量无显著影响,但更高浓度外源Se(IV)和Se(VI)却显著抑制了叶绿素合成.低浓度外源Se(IV)和Se(VI)均使小白菜叶片谷胱甘肽过氧化物酶(GSH-Px)活性上升,膜质过氧化物(MDA)含量下降,对超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性及脯氨酸含量无显著影响;高浓度硒使MDA含量、脯氨酸含量及SOD活性上升,而使GSH-Px活性和CAT活性下降;外源Se(IV)和Se(VI)均使过氧化物酶(POD)活性降低.研究发现,低浓度外源Se(IV)和Se(VI)均提高了小白菜的抗氧化作用,从而促进小白菜叶片叶绿素的合成和生长,高浓度时则相反;低浓度硒的抗氧化作用和高浓度硒的过氧化作用均以Se(VI)大于Se(IV).说明硒酸钠的有效性和毒害作用均大于亚硒酸钠.  相似文献   

10.
盐胁迫下胡杨愈伤组织生理生化特性   总被引:2,自引:1,他引:2  
目的:探讨胡杨愈伤组织的耐盐性与生理生化指标的关系。方法:不同浓度NaCl胁迫下,对胡杨愈伤组织的丙二醛(MDA)含量、过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性以及酯酶同工酶、过氧化物酶同工酶、超氧化物歧化酶同工酶酶谱进行研究。结果:随着盐浓度的增加,丙二醛(MDA)含量逐渐升高;从三种保护酶活性来看,过氧化物酶(POD)和过氧化氢酶(CAT)活性均呈先上升后下降的趋势,在70mmol/L NaCl胁迫下达到最高值,POD、CAT酶活分别为2748u/g.min和152u/g.min,分别比对照高104%和72%;超氧化物歧化酶(SOD)活性则呈先降低后稍上升的趋势,总体均比对照低。过氧化物酶同工酶的第2、3条酶带在70mmol/L NaCl胁迫下颜色最深,且酶带较宽;超氧化物歧化酶同工酶的第1条酶带仅在未经盐胁迫时存在,说明该酶带所代表的酶对盐很敏感;第4条酶带随盐胁迫浓度加大先消失后出现,可能是愈伤组织逐渐适应盐胁迫的结果。结论:经盐胁迫的胡杨愈伤组织中,POD和CAT酶主要起保护作用;结合同浓度盐胁迫下愈伤组织的形态观察,总体上看,胡杨愈伤组织能较好地耐受70mmol/L NaCl。  相似文献   

11.
Abstract

Evaporation and condensation processes at a liquid surface of methanol were investigated at room temperature with a microcanonical molecular dynamics computer simulation technique. The condensation coefficient (the number ratio of condensed molecules to incident ones) was estimated by comparing two types of autocorrelation functions, and found to be less than unity, which is in qualitative agreement with experiments. A variety of complex dynamic phenomena were observed at the surface.  相似文献   

12.
盐胁迫下两个亚麻品种幼苗的生理生化特性   总被引:2,自引:0,他引:2  
目的:探讨两个亚麻品种('双亚5号'和'范妮')幼苗对盐胁迫的生理反应.方法:当'双亚5号'和'范妮'的种苗长出第二片真叶时,对其进行不同浓度的NaCl胁迫(0、70、100、150、200、250mmol/L),处理7d后研究其不同盐浓度胁迫下的丙二醛含量、过氧化物酶和过氧化氢酶活性、酯酶同功酶和过氧化物酶同功酶谱带变化.结果:获得了盐胁迫下'双亚5号'和'范妮'幼苗的生理生化数据和图谱.结论:在100mmol/L NaCl胁迫后,'双亚5号'幼苗POD和CAT酶活性均达到峰值;在200mmol/L和100mmol/L NaCl胁迫后,'范妮'幼苗的POD和CAT酶活性分别达到最大值.对于各组处理,'范妮'幼苗的POD和CAT酶活性均明显高于'双亚5号'幼苗的.因此,认为'范尼'幼苗比'双亚5号'幼苗更具耐盐潜力.  相似文献   

13.
Methane (CH4) oxidation and the methanotrophic community structure of a pristine New Zealand beech forest were investigated using biochemical and molecular methods. Phospholipid-fatty acid-stable-isotope probing (PLFA-SIP) was used to identify the active population of methanotrophs in soil beneath the forest floor, while terminal-restriction fragment length polymorphism (T-RFLP) and cloning and sequencing of the pmoA gene were used to characterize the methanotrophic community. PLFA-SIP suggested that type II methanotrophs were the predominant active group. T-RFLP and cloning and sequencing of the pmoA genes revealed that the methanotrophic community was diverse, and a slightly higher number of type II methanotrophs were detected in the clone library. Most of the clones from type II methanotrophs were related to uncultured pmoA genes obtained directly from environmental samples, while clones from type I were distantly related to Methylococcus capsulatus. A combined data analysis suggested that the type II methanotrophs may be mainly responsible for atmospheric CH4 consumption. Further sequence analysis suggested that most of the methanotrophs detected shared their phylogeny with methanotrophs reported from soils in the Northern Hemisphere. However, some of the pmoA sequences obtained from this forest had comparatively low similarity (<97%) to known sequences available in public databases, suggesting that they may belong to novel groups of methanotrophic bacteria. Different methods of methanotrophic community analysis were also compared, and it is suggested that a combination of molecular methods with PLFA-SIP can address several shortcomings of stable isotope probing.  相似文献   

14.
Expression of the 1,2-dihydroxynaphthalene dioxygenase (nahC) gene from Pseudomonas putida in tobacco transgenic plants produces notable phenotypic and biochemical changes: retarded growth and rooting and earlier flowering; chlorotic and necrotic spots on leaves; and a threefold increase in the total phenolics in the leaves of 6-week-old plants (94.51 g/g fr wt as compared to 33.18 g/g fr wt in the control) and in the phenylalanine-ammonia lyase activity in 4-week-old plants (0.035 U/g fr wt as compared to 0.014 U/g in the control plants of the same age). The transgenic plants expressing the nahC bacterial gene may serve as a model to study the putative functions of dioxygenases and phenol compounds in plant growth, development, and stress responses.  相似文献   

15.
L-2,4-Diaminobutyrate (DAB) acetyltransferase (DABAcT) catalyzes one of the key reactions of biosynthesis of the bacterial osmoprotectant ectoine--acetylation of L-2,4-DAB yielding Ngamma-acetyl-2,4-DAB. Gene ectA encoding DABAcT was cloned from DNA of the halotolerant methanotroph Methylomicrobium alcaliphilum 20Z and expressed in Escherichia coli with an additional six His residues at the C-terminus. Homogeneous enzyme preparation with specific activity 200 U/mg was obtained by affinity metal-chelating chromatography. DABAcT was found to be a homodimer with molecular mass 40 kD. The enzyme is most active at pH 9.5 and 20 degrees C, and its activity increased threefold in the presence of 0.1-0.2 M NaCl or 0.2 M KCl. The Km values of recombinant DABAcT measured at the optimal pH and temperature in the presence of 0.2 M KCl were 460 and 36.6 microM for L-2,4-DAB and acetyl-CoA, respectively. The enzyme is specific for L-2,4-DAB and acetyl-CoA and is also active against propionyl-CoA (20%). Zn2+ and Cd2+ at 1 mM concentration completely inhibit the recombinant enzyme; 10 mM ATP inhibits 26% of the enzyme activity, whereas EDTA, o-phenanthroline, ADP, NAD(P), and NAD(P)H do not significantly effect the enzyme activity. The possible participation of DABAcT in regulation of ectoine biosynthesis in M. alcaliphilum 20Z is discussed.  相似文献   

16.
目的:从甲基营养菌MP681中扩增甲醇脱氢酶(MDH)基因,在大肠杆菌中表达并检测其活性,同时在MP681中考察该基因对吡咯喹啉醌(PQQ)产生的影响。方法:根据MP681基因组序列设计引物,PCR扩增靶基因mdh,构建表达载体,考察活性,利用接合转移转化至MP681,考察PQQ的合成。结果:扩增得到甲基营养菌MP681甲醇脱氢酶基因,在大肠杆菌中的表达产物能够催化甲醇脱氢;将携带mdh基因的质粒转入MP681后,PQQ产量略有提高。结论:获得编码MDH的基因,该基因能够在大肠杆菌中表达,且表达产物具有生物活性;甲醇脱氢酶基因表达对宿主菌的PQQ合成可能有一定影响。  相似文献   

17.
It may be questioned whether potential models that have been developed independently for two different pure compounds would behave properly when used in computer simulations of mixtures of these compounds. Since they are optimized for the pure compounds there is no guarantee whatsoever that the terms describing the interaction between dissimilar molecules are correct. If the simulational and experimental values of several thermodynamical properties of the mixture relative to those of the pure compounds agree closely, however, this strongly indicates that no separate optimizations need be carried out for the mixtures. Here we present the results of isothermal-isobaric Molecular Dynamics simulations of liquid methanol, water and equimolar methanol-water mixtures, using simple point charge models. The potential parameters of the models for the pure liquids had been independently optimized. No adjustment of parameters was made for the mixture, but nonetheless the experimental volume contraction and excess enthalpy upon mixing were reproduced almost perfectly.  相似文献   

18.
Russian Journal of Plant Physiology - The physiological, morphological, and biochemical characteristics of seedlings of common amaranth (Amaranthus retroflexus L.), blue licorice (Agastache rugosa...  相似文献   

19.
低温下壳聚糖处理对黄瓜幼苗生理生化特性的影响   总被引:37,自引:0,他引:37  
50 mg/L的壳聚糖处理减轻了低温对黄瓜幼苗膜的伤害,低温(6℃)处理4 d后,幼苗膜透性和MDA含量明显低于对照,并且显著减缓了低温导致的光合速率、实际光化学效率(ФPS Ⅱ)、光化学猝灭系数(qP)和1光系数(F’v /Em’)的下降;同时,处理使抗氧化酶SOD、POD、CAT和APX活性提高,可溶性蛋白和脯胺酸含量增加.因此,壳聚糖处理增强了黄瓜幼苗的抗冷性,保护了膜系统,提高了活性氧清除能力,减轻了低温对光合机构的破坏.  相似文献   

20.
通过营养液栽培,研究不同矿质营养的缺乏对黄瓜叶片组织生理生化特性的影响。结果表明,缺铜对植株生理影响最大,在各处理中,叶片组织的可溶性糖含量最低,木质素含量也处于较低水平,而相对电导度则最高,所测定的4种保护酶(POD、PPO、PAL、SOD)活性也最低。其次是锌,缺锌造成了相对电导度的增加,可溶性糖含量和木质素含量的下降,除PAL活性外,其余3种酶活性也处于次低的位置。缺锰主要导致了叶片组织可溶性糖含量、木质素含量以及PAL活性的较大幅度的下降。缺钙主要降低了叶片组织中可溶性糖含量和SOD活性。比较而言,硼和铁的缺乏影响较小。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号