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1.
盐度对桐花树幼苗根茎叶膜保护系统的影响   总被引:9,自引:4,他引:9  
研究了红树植物桐花树幼苗根茎叶各器官在不同盐分处理下,蛋白质含量、超氧化物歧化酶、过氧化物酶和过氧化氢酶及膜脂质过氧化作用的变化情况。结果表明:随着盐分的增加,叶和根的蛋白质含量均有所下降,而茎的蛋白质含量则有所升高。各器官膜脂质过氧化作用随盐度增加都有增加.过氧化物酶和过氧化氢酶活性随盐度增加则有微弱下降或基本保持稳定,而超氧化物歧化酶活性则表现出较为明显的下降趋势,讨论了桐花树幼苗在盐度存在情况下膜脂质过氧化作用和膜保护酶系统的关系。  相似文献   

2.
培养盐度对海莲和木榄幼苗膜保护系统的影响   总被引:17,自引:3,他引:14  
研究两种红树植物海莲和木榄幼苗叶片在不同培养盐分处理下,蛋白质含量、超氧化物歧化酶及膜脂质过氧化作用的变化情况.结果表明:随着盐分的增加,幼叶的蛋白质含量在总体上呈下降的趋势,海莲从对照的2.2mg/gFW下降到30‰盐度时的0.8mg/FW,木榄的蛋白质变化则较为复杂.具有膜保护作用的超氧化物歧化酶活性在总体上则逐步随盐度增加而增加,海莲幼叶的SOD活性从对照的31个活性单位/mgPr上升到30‰盐度的95个活性单位/mgPr,木榄的SOD活性升高则更为明显.与SOD变化相反,膜脂质过氧化作用随盐度升高则表现出较为明显的下降趋势(木榄)和在低盐度下降,高盐度上升的变化(海莲).讨论了海莲和木榄幼叶在不同盐度条件下膜脂质过氧化作用和膜保护酶系统的关系,表明脂质过氧化作用和SOD保护作用是盐胁迫的主要过程,可作为红树植物耐盐性的参数.  相似文献   

3.
以两相分配法从红树植物白骨壤和秋茄幼苗叶中提取的高纯度质膜囊泡为材料,鉴定出质膜硝酸还原酶(NR)的存在,白骨壤幼苗叶质膜NR与胞质NR比较活性较低,但二者均与反应体系NaCl浓度有关;白骨壤和秋茄幼苗叶细胞质膜NR活性也受培养液盐度的影响;在一定盐度范围内(白骨壤0‰-30‰;秋茄0‰-20‰)NR活性随盐度增高而增强,白骨壤在30‰盐度时活性达到最高,比对照高89.5%,秋茄在20‰盐度对NR活性比对照增强192%。当盐度更高时,NR活性下降。表明:两种红树植物对NO3^-的吸收和利用均受培养盐度的影响,秋茄对盐度的反应较白骨壤敏感。  相似文献   

4.
盐度对秋茄幼苗的生长和水分代谢的效应   总被引:12,自引:9,他引:12  
探讨了不同盐度海水砂培 45~47 d的秋茄幼苗的生长特性和水分代谢状况。结果表明:5~10‰的低盐度对高度生长以及5~15‰的低盐度对根、茎、叶和总生物量具有正刺激效应;高盐度(20‰以上)起抑制作用。随着盐度的提高,叶片变小,根/苗、根/叶生物量率曲线呈上升(盐度 0~5‰)至平缓(盐度 5~15‰)到上升(盐度 20~25‰)至陡升(盐度 25~35‰)趋势。盐度的提高,叶片水势、蒸腾速率、气孔导度降低而扩散阻力提高。最适生长的盐度在5~15‰之间;更高的盐度虽可生长,但已受胁迫,表现为生态抗盐适应性。  相似文献   

5.
白骨壤(犃狏犻犮犲狀狀犻犪犿犪狉犻狀犪)是红树林生态系统的先锋植物.为适应低温、高盐、淹水、土壤缺氧和潮水冲击等诸多不良因子的影响,白骨壤已特化出一套适应机制:包括形态结构、水分、光合作用、蒸腾作用、气孔导度、生物量和生长等.本文综述了白骨壤对低温、盐度、土壤、潮水浸淹、风浪作用等环境因子的生态响应,指出白骨壤作为先锋树种和乡土树种,对环境具有较强的耐受性和适应性并能有效保护生态安全,可作为红树林造林优先选择的树种,应深入研究其与各环境因子的生态响应机制,为红树林造林地选择及生态修复提供科学依据.  相似文献   

6.
萘胁迫对白骨壤种苗萌生及抗氧化作用的影响   总被引:8,自引:0,他引:8  
采用砂基栽培.研究污染物多环芳烃萘(Nap)不同暴污强度(0、20、40、60、80、100mg/L)和暴污时间的环境胁迫下.对红树植物白骨壤(Auicennza marina)幼苗萌发初期的萌生及子叶超氧化物歧化酶(SOD)、过氧化物酶(POD)活性和膜脂质过氧化作用的影响.结果表明:Nap污染胁迫对红树白骨壤幼苗的萌生.随着暴污强度和暴污时间的增加而影响愈加明显;幼苗萌发初期抗Nap胁迫生长的浓度范围在40mg/L以下.在暴污的较短时间内.幼苗子叶SOD活性有着积极的响应;随着暴污时间的延长.SOD活性则逐步受到抑制.达30d后酶活性略普遍低于对照.受Nap的胁迫.幼苗子叶POD活性提高;POD有效防御Nap胁迫的浓度范围在60mg/L以下.幼苗子叶中抗氧化防御系统.在萌发初期对有效防御膜脂质过氧化的Nap胁迫浓度在60mg/L以下.结果表明.白骨壤幼苗的萌发初期,对Nap污染的环境胁迫有较强的抗性能力.  相似文献   

7.
广西北海大冠沙红树林为开阔沙滩白骨壤林。为了解沙丘移动的规律及其对红树林的危害,从1992年4月到1995年7月对一处于发育初期的活跃沙丘进行实地观测。结果表明,30多年前沙丘才开始在林内发育和移动。沙丘高可达88cm,每年移动12.64m,在4~7月大潮期移动尤其迅速。沙丘在3.25年面积扩大了2.44倍。研究样地白骨壤植株高49.5~67.9cm,86%的植株因被沙丘埋没而死亡。在埋没过程中存活下来的植株继续受侵蚀、呼吸根上的固着动物和人为活动的危害。沙丘的移动引起白骨壤林的明显退失和生境的分化。  相似文献   

8.
几种红树植物叶片和胚轴碳氢氮含量   总被引:5,自引:0,他引:5  
探讨了红树植物秋茄、白骨壤、桐花树、海莲、木榄、红海榄、正红树和角果木的叶片及秋茄、海莲和木榄的胚轴,在生长发育过程中。C、H、N素的含量动态,结果表明:幼叶、成熟叶和黄叶C、H、N素的含量范围:含C量分别为418.4~496.5mg/g、442.4~501.5mg/g和450.7~542.1mg/g;含H量分别为54.O~61.8mg/g、53.9~61.4mg/g和52.8~64.1mg/g;含N量分别为11.3~39.0mg/g、10.6~30.9mg/g和5.1~18.6mg/g,随着叶片的生长、发育至衰老。N素含量降低,C、H含量也发生一定的变化,随着胚轴在母树上萌生至成熟:秋茄、海莲和木榄,含H量分别提高了15.7%、11.3%和16.7%;而含N量则分别降低了44.O%、13.7%和42.8%;含C量秋茄变化不明显,海莲和木榄则分别略为降低。  相似文献   

9.
通过栽培污灌试验,研究了玉米幼苗铅胁迫下的脂质过氧化、膜系统伤害、叶绿素含量的变化关系.试验结果表明:随铅处理强度的增加,过氧化物酶(POD)活性下降,脂质过氧化作用加强,膜透性增加,细胞内的电解质大量外渗,叶绿素含量下降.由此初步地揭示了铅对玉米幼苗危害与自由基代谢平衡的关系.  相似文献   

10.
水杨酸对温度胁迫下紫御谷幼苗生长及光合特性的影响   总被引:1,自引:0,他引:1  
以紫御谷为材料,研究了水杨酸对温度胁迫(高温和低温)下紫御谷幼苗生长及光合特性的影响,结果表明:①高温和低温胁迫显著降低了紫御谷幼苗的根冠比、根系活力、总根长和平均根直径,使根系生长受到抑制,而水杨酸处理则提高了其根冠比、根鲜物质量、茎鲜物质量和根系活力;②高温胁迫显著降低了紫御谷叶片的叶绿素a、总叶绿素质量分数和净光合速率,而水杨酸处理显著提高了紫御谷叶片的净光合速率.低温胁迫使紫御谷幼苗叶片的净光合速率、气孔导度和蒸腾速率均显著低于常温对照,而水杨酸处理后,叶片的净光合速率、气孔导度和蒸腾速率均有所升高.③高温胁迫下,紫御谷幼苗的初始荧光(Fo)、光化学量子效率(Fv/Fm)和光下PSⅡ实际光化学效率(ΦPSⅡ)与常温对照相比差异不显著,而低温胁迫下的Fv/F和ΦPSⅡ则显著低于常温对照,喷施水杨酸后Fv/Fm和ΦPSⅡ均低于低温处理组,且Fv/Fm差异显著,由此推断低温胁迫可能使PSⅡ反应中心受到不可逆的损害.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

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