NaCl和Na2CO3胁迫对盐爪爪种子萌发过程中生理生化变化的研究

以盐生植物盐爪爪种子为材料,比较不同浓度中性盐(NaCl)和碱性盐(Na2 CO3)胁迫对其种子萌发过程中生理指标的影响.结果表明,0～100 mmol/L NaC1处理后盐爪爪萌发种子中丙二醛含量无显著变化,而0～100 mmol/L Na2CO3处理后丙二醛含量显著升高;NaCl处理的萌发种子中可溶性糖变化较平稳且呈现上升趋势,Na2CO3处理的种子可溶性糖先升高后降低;0～ 100 mmol/L NaCl处理后盐爪爪萌发种子中脯氨酸含量基本保持不变,而0～100 mmol/L Na2CO3处理后脯氨酸含量急剧上升;NaCl处理后可溶性蛋白上升幅度大于Na2CO3处理后上升幅度,二者的差异达到极显著水平.研究发现,盐爪爪种子萌发对于低浓度中性盐(NaCl)胁迫具有较强的耐性和抗性,而在碱性盐(Na2CO3)的胁迫下其萌芽受到一定的抑制.     

寒地水稻芽期耐碱鉴定指标分析与筛选

利用浓度为0.20％的Na2CO3+ NaHCO3混合碱对173份水稻材料做发芽试验处理,结果表明:胚根对碱胁迫反应最敏感,相对胚根长平均值仅为0.276,相对根干重为0.348;碱环境下发芽率较其他指标变化不明显;供试材料间相对芽鞘长差异较大,但芽鞘对碱环境的反应与耐碱性无关.通过各指标与耐碱级别的相关系数分析,认为影响耐碱级别划定的重要指标有相对芽干重、相对芽长、相对根干重、相对胚根长、相对根条数.通过逐步回归分析确定相对芽长、相对芽干重和相对根干重是水稻芽期耐碱的3大指标,用其可建立耐碱级别判定方程:Y=9.234 -4.506 X1 -2.167X2-2.621X3;还可以相对芽长、相对胚根长、相对根条数、相对芽干重、相对根干重5项鉴定指标建立耐碱级别判定方程:Y=11.251 -3.6747X1-1.641 X2 -1.179X3 -3.900 X4 - 1.973 X5,两方程结合应用则判定结果更加准确.分析显示,种质资源交流可丰富基因多样性,同时还可提高新品种的耐盐碱性能及其他抗逆性.     

Characteristics of Brittle Failure and Stress Drop Under Triaxial Loading and Unloading

The characteristics of deformation failure and stress brittle drop of granite under loading and unloading conditions are studied respectively based on two unloading stress path cases and conventional triaxial compression experiments. The experiments show that the primary deformation of rock is rebound or tension in the (main) unloading direction, but plastic deformation in the non or sub unloading direction is not significant. And the curves of stress strain after peak strength present obvious brittle. Whilst the primary deformation of rock under loading is axial pressure deformation, and plastic deformation increases with the raise of confining pressure. The fracture is characterized by strong tensile, and all tensile cracks are fully developed. Furthermore, when the rock samples are unloaded in two directions, and even normal to unloading direction, sub unloading annular tensile cracks are produced. The shear fractures is obvious comparatively when confining pressure becomes higher, and it develops following tensile cracks with more micro tension cracks formed in two sides along shear plane. But the fracture is characterized by shear under conventional triaxial compression with little tensile cracks; the coefficients of brittles stress drop of granite is increased with the growth of confining pressure under conventional triaxial compression and reduced under unloading. When the initial confining pressure is the same, the coefficients of brittles stress drop under unloading is less than that under loading. In SchemeⅡ, the coefficients of brittles stress drop reaches negative when initial confining pressure is up to 30 MPa, and the one （R）is RⅢ>RⅠ>RⅡ in three test cases.     

Test on engineering properties of unsaturated undisturbed loess Q2

A series of triaxial shear tests with controlled constant confining pressure are conducted to study the failure modes, effects of deformation, strength and yield properties of unsaturated undisturbed loess Q2, with improved SJ-1A triaxial shear equipment. The test results show that the failure mode of unsaturated undisturbed loess Q2 is shear failure with the rupture angle between 55 and 61 degree; Shear dilatancy is shown under low confining pressure, and shear shrinkage is shown under high confining pressure; The stress-strain curves of undisturbed loess Q2 will change from perfectly plastic to weak strain softening as the confining pressure increases; A effective method is suggested to identify the field stress of undisturbed loess Q2 under triaxial shear condition with the curves of - q/p ; when the confining pressure increases, the deviatoric yield stress qy has a logarithmic relationship with net mean yield stress py .     

The influence of stress sensitivity on productionof hydraulically-fractured tight gas wells

This paper takes Sulige Gas Field as a case study and used three methods including laboratory experiments,production performance analysis and reservoir simulation to study the influence of stress sensitivity on production of fractured tight gas wells.The results show that the fracture length and conductivity of hydraulically created fracture are reduced more than 50%,and the stress sensitivity of hydraulically created fracture is stronger than that of matrix.With the increase of gas production,the influence of stress sensitivity becomes stronger,and finally results in 18% reduction of gas production,and hydraulically created fractures play an important role in the influence of stress sensitivity.     

Thermo-mechanical coupling analysis of dual-steel-disc of wet multi-disk clutch

To solve the failure problem of power transmission caused by warping, crackle on dual-steel-disc of wet multi-disk clutch, a shipborne wet multi-disk clutch is taken as a research object, models of generation and distribution of friction heat flux are built and numerical methods to solve temperature field and coupled stress field are put forward. Research methods of thermo-mechanical coupling problem of wet multi-disk clutch are proposed. The thermo-mechanical coupling phenomenon of dual-steel-disc is investigated, and the failure mechanism of dual-steel-disc of wet multi-disk clutch is revealed. In the engagement process, the results of temperature field show that the temperature of the dual-steel-disc gradually increases from the inner edge to the outer edge, and the temperature of friction surface reaches the highest at 2.6 s in the 3-second-engagement. The rules of thermal stress distribution are attained that the circumferential tensile thermal stress appears in the region close to the inner edge, while the radial tensile thermal stress appears in the region close to the outer edge. The theoretical basis to solve the thermal failure problem of dual-steel-disc of wet multi-disk clutch is provided.     

Interactive responses to water deficits and crop load in olive (Olea europaea L., cv. Morisca). II: Water use, fruit and oil yield

To understand the relations between water use and yield in response to crop load, two experiments were conducted in olive (cv. Morisca), during six consecutive years (2002-2007) in an experimental orchard located in Badajoz, Southwest Spain. Experiment 1, assessed the responses during the early years of the orchard (2002-2004) using four irrigation treatments that applied fractions of the estimated crop evapotranspiration (ET_c) (125%, 100%, 75% and 0%) and three crop load levels (100%, 50% and 0% of fruit removal, termed Off, Medium and On treatments). Experiment 2 assessed the response of more mature trees (2005-2007) to three irrigation treatments (115%, 100%, and 60% of ET_c) and the natural crop load which were Off, On, and Medium in 2005, 2006 and 2007, respectively. Yield was reduced by water deficits and so did the estimated tree transpiration which was linearly related to yield (y = 1.2302x − 21.15, R² = 0.8864), showing the high sensitivity of cultivar Morisca to water deficits. The relations between fruit number and fruit weight showed that high crop loads had lower fruit weights and oil yield, a decrease that was more pronounced as water deficits increased. The yield response to water supply in the control and excess treatments, and the observations on the water relations of these two treatments suggest that the calculations made using the FAO method (Doorenbos and Pruit, 1974) with the crop coefficient proposed by Pastor et al. (1998) and the reduction coefficient (Fereres et al., 1982) to apply 100% of ET_c in the control treatment, underestimated the ET_c of the orchard. The results indicate that, although the absence of fruits lead to reduced water use as compared to situations of medium and high crop loads, canopy size was much more determinant of orchard water requirements than crop load.     

水稻盐胁迫相关基因sos5的克隆与序列分析

采用RT-PCR扩增的方法,从水稻(Oryza sativa)中克隆获得了1 574 bp的cDNA片段。基因测序和序列同源性分析结果表明,所克隆的基因片段包含1 284 bp的开放阅读框,编码一个含有427个氨基酸的多肽,该蛋白与拟南芥SOS 5蛋白同源性达45.6%,与小麦同源性达71%。     

高渗液浸种对橡胶树种子活力和幼苗生长的影响

在橡胶树种子催芽过程中,用NaCl、甘露醇、聚乙二醇(PEG6000)溶液模拟水分胁迫进行浸种处理,研究高渗液胁迫对种子活力指数、幼苗株高、茎粗和根冠比的影响,并比较室温(26～27℃)、低温(5℃)、高温(45℃)条件下幼苗的胁迫伤害表现。结果表明:高渗胁迫降低了种子活力、抑制了幼苗地上部分的生长(株高和茎粗),但对幼苗生物量和根冠比的影响因高渗液种类及浓度而异,主要表现在PEG以及浓度为0.15、0.20mol/L甘露醇浸种提高了根冠比,而NaCl降低根冠比;高温条件下,幼苗受害比低温、室温更快更大,表现在根系细胞膜质透性的急剧增加和蒽酮反应现象的出现,但不同高渗液种类间存在差异。甘露醇、PEG浸种处理幼苗根系细胞膜质透性急剧增加,并在胁迫6h时出现蒽酮反应现象,NaCl浸种处理幼苗根系细胞膜质透性的增幅较小,且在胁迫6h时无蒽酮反应现象,可能与其根部累积盐离子有关。     

不同基因型澳洲坚果对磷胁迫反应的差异研究

通过常磷和缺磷溶液培养,对8个不同基因型澳洲坚果的生长情况和吸收利用磷营养的特性进行了研究,探讨了不同基因型澳洲坚果对磷胁迫反应的差异.结果表明,不同基因型澳洲坚果对可溶性磷的吸收能力存在差异,吸收的磷量可达到自身固有磷量的12.28%～77.78%;H2、246、Oc和800等基因型植株的根、地上部以及单株鲜重和干重均表现出受磷胁迫影响较大的特点;在缺磷条件下,H2基因型植株的磷生物利用率下降(仅为常磷处理的93.80%),其他基因型均有所上升,尤其是246和Oc基因型植株的磷生物利用率分别为常磷处理的184.38%和141.67%,说明H2、246和Oc等3个基因型对磷胁迫比较敏感.