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1.
以引种栽培的4年曼地亚红豆杉为材料,研究了其叶片低温半致死温度与膜保护系统随气温下降的变化,结果表明,低温半致死温度降低的同时,O2水平降低,SOD,POX活性增强,Vc含量增加,使膜保护系统自由苊的清除能力加强,MDA含量下降,膜保护系统的适应性导致低温半致死温度的下降是抗寒性提高的生理基础。  相似文献   

2.
云锦杜鹃低温半致死温度对自然降温的适应   总被引:3,自引:0,他引:3  
以云锦杜鹃为材料,研究了其叶片低温半致死温度与膜保护系统随气温下降的变化.结果表明,低温半致死温度降低的同时,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性增强,使膜保护系统自由基的清除能力增强,超氧化物阴离子自由基(O2-)水平降低,丙二醛(MDA)含量降低.膜保护系统的适应性变化导致低温半致死温度的降低是抗寒性提高的生理基础.  相似文献   

3.
以草珊瑚为材料,研究了其叶片低温半致死温度与水分和渗透调节物随气温下降的变化.结果表明,低温半致死温度降低的同时,叶片相对含水量、自由水和淀粉含量下降,束缚水、可溶性糖、可溶性蛋白和脯氨酸含量增加.这些物质的适应性变化导致低温半致死温度的下降是抗寒性提高的生理基础.  相似文献   

4.
研究了南方红豆杉叶片低温半致死温度与水分和渗透调节物质随气温下降的变化。结果表明,低温半致死温度降低的同时,叶片饱和含水量、自由水和淀粉含量下降,束缚水、可溶性糖、可溶性蛋白和游离脯氨酸 含量增加。这些物质的适应性变化导致低温半致死温度的下降是抗寒性提高的生理基础。  相似文献   

5.
以草珊瑚为材料,研究了其叶片低温半致死温度与水分和渗透调节物随气温下降的变化。结果表明,低温半致死温度降低的同时,叶片相对含水量、自由水和淀粉含量下降,束缚水、可溶性糖、可溶性蛋白和脯氨酸含量增加。这些物质的适应性变化导致低温半致死温度的下降是抗寒性提高的生理基础。  相似文献   

6.
实验以人工栽培的桅子为材料,研究了其叶片低温半致死温度及脱落酸、赤霉素随气温下降的变化,结果表明,低温半致死降低的同时,脱落酸含量上升,赤霉素含量下降,尤其值得引起关注的是脱落酸含量与工赤霉素含量的比值(记为k)的变化表现出与低温半致死温度更密切的关系(R=-0.9920),因此在抗寒锻炼中不同激素间的配比和平衡调节比单一类型激素的变化更为重要,k的增大与抗寒性加强关系极其密切。  相似文献   

7.
南方红豆杉抗寒性的变化与内源激素的关系   总被引:12,自引:1,他引:12  
研究了南方红豆杉叶片低温半致死温度与其4种内源激素的含量随气温下降的变化。结果表明低温半致死温度降低的同时,脱落酸(ABA)含量和ABA/GA增加,赤霉素(GA)、生长素(IAA)含量下降,它们与其抗寒力的变化有明显的相关性。玉米素核甘(ZR)含量先降后升,与冬芽萌发有关。可见植物激素通过某种平衡状态启动抗寒基因表达和维持膜结构功能的稳定在植物抗寒性调控中起重要作用。  相似文献   

8.
曼地亚红豆杉的半致死温度与对低温的适应性   总被引:5,自引:0,他引:5       下载免费PDF全文
红豆杉树皮是一种最重要的提取紫衫醇的原料,但其生长缓慢,资源匮乏,而曼地亚红豆杉的自然杂交品种叶片中的紫衫醇的含量很高,生长迅速,可通过大力栽培解决原料不足的问题。在引种栽培蔓地亚红豆衫的试验过程中,抗寒性是决定其是否能够引种栽培成功的关键因素之一,而半致死温度能较直观,准确地反映植物的抗寒能力,半致死温度的测定常采用电导法。采用电导法对引种栽培的2个曼地亚红豆衫(T.media)品种Hicksii和Dark Green Spreader(DGS)进行低温半致死温度的测定,并与其生境中的自然温度变化相比较,结果表明,在自然降温的过程中,两个曼地亚红豆衫杂交品种的低温半致死温度随气温的下降而不断的降低,两品种的低温半致死温度分别为-13.3℃和-12.6℃,均对引种栽培地低温有较强的适应性,又Hicksii品种比Dark Green Spreader品种的抗寒能力略强。因此从理论上讲,两种曼地亚红豆衫品种均可在栽培地及与栽培地相同的生境下栽培成功。  相似文献   

9.
自然低温胁迫对毛竹生理生化特性的影响应   总被引:1,自引:0,他引:1  
选用3种不同年龄段毛竹作为试验材料,通过对自然越冬状态下毛竹各项生理指标和低温半致死温度的测试,研究了毛竹抗寒能力及其有关生理生化特性的变化。结果表明:从12月5日到翌年2月5日自然低温过程中,随着温度的变化,毛竹1年生、2年生实生苗和竹林中40 a以上1年生秆毛竹(1年生成竹)的叶绿素含量呈先降低后升高再降低的趋势,总降幅分别为21.46 %、42.38 %、22.76 %;SOD活性和MDA含量的变化趋势类似,先升高后降低;而POD活性为先升高后降低再升高;可溶性蛋白的含量呈先升高后持续降低,总降幅分别为16.43 %、29.46 %、29.61 %;而可溶性糖含量成竹高于1年生和2年生竹,但消耗量低于1年生和2年生竹;半致死温度为1年生(-13.697℃)较高,2年生(-15.426℃)次之,成竹(-18.393℃)较低。半致死温度与12月上旬的MDA含量呈显著负相关,与1月下旬的可溶性糖含量呈极显著正相关。由此表明,毛竹具有较强的抗寒性,并随着年龄的增长,植株的抗寒能力提高。  相似文献   

10.
低温胁迫对烟草保护性酶类及氮和碳化合物的影响   总被引:5,自引:0,他引:5  
在6℃和10℃低温胁迫下,研究了2个烟草品种的膜透性、保护性酶类活性和N,C化合物含量的变化.结果表明:2个烟草品种幼苗的膜透性都随着胁迫温度的降低和胁迫时间的增加而增加;酶活性的变化趋势为:CAT和SOD随着胁迫温度的降低和胁迫时间的增加而降低,POD的变化则有相反的趋势;蛋白质含量在低温胁迫下下降,脯氨酸含量则增加,并且脯氨酸在叶片中的变化较为剧烈;可溶性总糖和蔗糖含量低温胁迫下在叶片中有所积累,而叶绿素a、叶绿素b和叶绿素总量则可能因叶绿体受损而下降.  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.
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   

13.
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   

14.
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   

15.
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   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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