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1.
光强对秋茄幼苗的生长和光合特性的影响   总被引:12,自引:0,他引:12  
研究了不同光强环境中秋茄幼苗的生长和光合特性的变化.结果表明,在弱光生境下,秋茄幼苗的高生长增加,抽条着生叶数和叶片的叶绿素含量均有所提高,但抽条基径变细,比叶重下降,说明秋茄幼苗的横向生长成弱,叶片变薄.随着光环境水平的下降,秋茄幼苗的相对生长率降低,净光合作用量下降.弱光生境降低了秋茄幼苗地下部根的相对生长,使整株植物的干物质生产有所下降.弱光生境中秋茄幼苗的最大光合速率、光饱和点、光补偿点和暗呼吸速率较低.在同一光生境中,10盐度降低了秋茄幼苗的最大净光合速率、光补偿点和暗呼吸速率,但对光饱和点影响不大.弱光生境可以缓和盐度对秋茄幼苗净光合速率的抑制.  相似文献   

2.
以海滨锦葵为实验材料,研究不同低温处理对海滨锦葵光合作用的伤害,探求海滨锦葵对低温胁迫的敏感温度,以及低温弱光对海滨锦葵的伤害.结果表明:在低温胁迫下,海滨锦葵的净光合速率(Pn)、光系统II实际光化学效率(ФPSII)、最大光化学效率(Fv/Fm)显著下降,说明随着温度的降低,海滨锦葵光化学活性受到抑制,13℃是其低温胁迫下的临界温度.低温弱光(6℃、200μmol·m^-2s^-1)处理4h后Fv/Fm下降了2.5%,而光系统I活性(△I/I0)下降了18.5%,说明在低温弱光条件下,海滨锦葵光系统I受到的伤害高于光系统II;在恢复过程中,光系统II在8h基本完全恢复,而光系统I和净光合速率在48h后仍没有恢复到正常水平,说明PSI的恢复速率成了光合作用的主要限制因素.  相似文献   

3.
通过分析光合速率和快速叶绿素荧光诱导动力学曲线,研究了乙烯诱导衰老过程中大豆叶片PSⅡ光化学特征的变化.随着大豆叶片的衰老,光合速率大幅度下降,但是Fv/Fm只有轻微下降.这表明,大豆衰老过程中光合速率的下降不是PSⅡ光化学活性下降造成的;随着衰老,光合机构中的QB降解,QB的降解可能是导致PSⅡ光化学活性下降的关键因素.叶绿素荧光猝灭分析表明,在衰老初期,非光化学猝灭NPQ是强光下耗散过剩激发能的一个重要机制,然而当叶片严重衰老时,PSⅡ反应中心的失活可能成为光合机构耗散过剩激发能的另一种有效机制.  相似文献   

4.
氮水平对水稻光合特性的影响   总被引:2,自引:0,他引:2  
用缺氮(ON)、低氮(LN)、中氮(MN)、高氮(HN)、超高氮(SN)盆栽土培的杂交水稻汕优64和金南风为材料,测定植株和叶片的生长状况、叶片总N含量、光合速率、光呼吸速率、气孔导度和叶肉导度的变化.结果表明:供试两品种随着施N量的增加,植株的分蘖数增多,株高增加,气孔密度减少, 叶片总N含量、叶绿素含量、光呼吸速率、叶肉导度等均增加.供试两品种的净光合速率变化存在差异,金南风叶片的净光合速率是随着施N量的增加而增加,但汕优64在HN和SN的条件下净光合速率反而下降,说明在HN和SN的水平上光合碳代谢的途径发生了变化,即光氧化环增加的幅度大于光合还原环.  相似文献   

5.
杂交稻汕优63剑叶光合特性的研究   总被引:11,自引:0,他引:11  
对杂交稻汕优63剑叶一生光合特性的研究表明:RuBPCase活性及叶肉导度(Gm)与净光合速率显著相关,它们的下降速度明显快于净光合速率及气孔导度(Gs)、碳酸酐酶(CA)活性、PSⅡ原初光化学效率(Fv/Fm)、光化学猝灭(qP)、全链电子传递速率(ETR)等光合参数的衰退速率。RuBPCase活性及叶肉导度(Gm)的下降可能是叶片衰老过程中光合速率下降的主要限制性因素。  相似文献   

6.
采用发光二极管(light-emitting diode,LED)研究不同光质补光对温室大豆(吉育47)叶片光合特性及产量的影响.结果表明:补光改变了大豆叶片光合速率日变化规律,使大豆叶片光合速率日变化曲线由"单峰"型变为"多峰"型;LED光源虽然可以延长光合作用时间,使大豆光合速率升高,光合能力增强,但对大豆叶片的胞间CO2浓度、气孔导度和蒸腾速率的影响不明显.与其它光源相比,LED蓝色光源下大豆的光合速率和叶绿素含量最高,大豆的株高最低,茎最粗,不易倒伏,单株产量最高,所以LED蓝光更利于温室大棚内大豆的生长.  相似文献   

7.
采用LI-6400便携式光合仪器测定并分析了不同干旱和光照强度胁迫下,药用植物马比木(Nothapodytes pittosporoides(Oliv.) Sleum.)叶片的光合响应。结果表明:马比木的光合特性对光合有效辐射(PAR)和土壤水分变化响应明显,弱光条件下(PAR<200μmol/(m2·s)),光补偿点(LCP)随土壤水分含量减小呈现先减小后增大趋势,表观量子效率(AQE)则呈逐渐减小趋势;强光条件下(PAR>600μmol/(m2·s)),光饱和点(LSP)先增加后减小,在水分含量10.5%~22.0%范围达到最大值,净光合速率(Pn)和水分利用率(WUE)处于稳定阶段且保持在最大值附近。马比木对弱光的利用能力更强,对强光也有较好的适应性;土壤水分含量10.5%是其耐旱极值,22.0%~25.8%较适合生长。  相似文献   

8.
采用温室盆栽试验,研究了土壤水分和大气湿度及其交互作用对甜瓜壮龄叶光合作用特性的影响.结果表明:轻度土壤水分胁迫下,气孔因素是导致甜瓜叶片光合速率下降的主要原因.土壤水分严重亏缺使甜瓜叶肉光合能力降低,引起胞间CO2积累,叶片光合速率与蒸腾速率同步下降.在土壤湿度极低时,较高的空气湿度有助于诱导气孔开张.土壤水分充足时,过高的空气湿度导致甜瓜叶片气孔导度下降,叶肉细胞CO2供应不足,光合速率降低.甜瓜生产中土壤湿度应不低于最大持水量的50%,空气湿度宜控制在70%以下.  相似文献   

9.
水分胁迫对楸树苗木光合特性的影响   总被引:3,自引:0,他引:3  
应用PEG处理人工模拟干旱胁迫环境条件,采用完全随机试验设计,在人工气候室研究了8个品种(类型)楸树1年生扦插苗在4种不同水分胁迫(CK、4%、8%和12%)下的光合特性.结果表明:水分胁迫下各品种(类型)楸树的净光合速率、蒸腾速率、气孔导度、胞间CO2浓度、Fv/Fm和Fv'/Fm'均降低.周2、光叶、梓树和南阳的净光合速率下降由气孔导度引起,而楸树、圆长、‘豫1'和金丝则由非气孔导度因素即叶肉细胞光合能力下降引起.综合表明,南阳、光叶、周2和金丝抗旱性稍强,其余4品种稍差.  相似文献   

10.
以中乐油2号和蓉油11号油菜为材料,通过盆栽试验,研究渍害胁迫及恢复进程中油菜幼苗叶片光系统Ⅱ(PSⅡ)光化学特性的变化。结果表明:随着渍害胁迫的加剧,两品种油菜叶片初始荧光(F)0、非光化学淬灭系数(qN)不断上升,最大荧光(Fm)、PSⅡ最大光化学量子产量(Fv/Fm)、PSⅡ实际光化学量子产量(Yield)、表观光合电子传递速率(ETR)、光化学淬灭系数(qP)不断下降,说明随着渍害胁迫的加剧,PSⅡ部分反应中心受到破坏,光合电子传递受阻,光能转换效率下降,发生明显光抑制;从第13d起进行恢复处理,所有叶绿素荧光参数均有所恢复,但仍未达到对照水平。可见,当渍害胁迫超出了油菜机体自我调节的阈值时,油菜叶片的部分光合机构发生不可逆的破坏,最终影响油菜的正常生长。  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 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   

13.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
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   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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