Zn2+ 对海滨木槿种子萌发及根伸长抑制效应的研究

探讨Zn2+对海滨木槿种子萌发及根伸长抑制效应对在污染严重的海滨栽种海滨木槿及海滨重金属污染植物修复具有重要意义。测定了不同Zn2+浓度梯度下的海滨木槿种子发芽率、发芽势及根的伸长量和生物量变化,结果表明,较低浓度的Zn2+能够促进海滨木槿种子萌发,但是海滨木槿种子萌发对高浓度Zn2+不敏感,只有Zn2+的浓度为400 mg/g时才对种子萌发表现出抑制作用。Zn2+对海滨木槿种子发芽的抑制效应远小于对根伸长和生物量的抑制效应。随着Zn2+胁迫浓度的升高,海滨木槿根的伸长量及生物量明显降低,海滨木槿根伸长抑制率与Zn2+的浓度有极好的正相关性。     

基于重组外膜蛋白P2的副猪嗜血杆菌抗体间接ELISA方法的建立

旨在建立一种基于重组副猪嗜血杆菌(HPS)外膜蛋白(Omp) P2的检测副猪嗜血杆菌抗体的间接ELISA方法.将重组表达的Omp P2纯化后作为ELISA包被抗原,建立了一种基于重组P2蛋白的间接ELISA方法,并对此方法的反应条件进行了优化.确定ELISA的最佳条件为:抗原包被浓度为1.5 μg/mL,被检血清1∶8...     

CdCl2对牛卵母细胞体外成熟及凋亡的影响

利用不同浓度(0,0.8,1.6,2.4 μg/mL)的氯化镉(CdCl2)对处理牛卵母细胞前后对其成熟率、凋亡率、Ca2分布、线粒体膜电位、Bcl-2与Bax的基因表达的影响,初步为重金属对雌性哺乳动物生殖细胞发育及细胞凋亡机制的进一步研究打下基础.利用0,0.8,1.6,2.4 μg/mL的氯化镉(CdCl2)处理...     

A non-ACC pathway for ethylene biosynthesis in Botrytis cinerea

Premature softening and tissue senescence occur in kiwifruit infected with Botrytis cinerea. While ethylene production is enhanced in infected fruit and B. cinerea produces ethylene on defined media in vitro the source of ethylene in this pathosystem is unclear. Ethylene production by B. cinerea was enhanced when methionine or ∝-keto-methylthiobutyric acid (KMBA) was added to a defined (modified Pratts) medium. Although 1-aminocyclopropane-1-carboxylic acid (ACC) did not stimulate ethylene production, ∝-aminooxyacetic acid (AOA) was inhibitory suggesting a role for a pyridoxal phosphate mediated enzyme reaction down stream from the methionine/KMBA stimulated ethylene biosynthetic pathway. Cobalt chloride (Co²⁺) was inhibitory, but after a 4-d lag period ethylene production from B. cinerea cultures containing methionine and Co²⁺ reached the same level as those without Co²⁺. [U ¹⁴C] methionine was converted to ¹⁴C-ethylene with high efficiency indicating that it is a direct precursor, while [2,3 ¹⁴C]-ACC did not yield radioactively labelled ethylene. These results suggest that the ethylene biosynthetic pathway in B. cinerea does not involve ACC as a precursor and that the enzyme responsible for synthesising ethylene is similar to, but different from, ACC oxidase from higher plants. The ethylene biosynthetic pathway in B. cinerea is yet to be determined.     

施氮水平对大豆光合作用及产量的影响

以绥农14为材料,采用砂培盆栽和测定整株光合作用的方法,研究了施氮水平对大豆光合作用及产量的影响。结果表明,大豆植株CO2吸收速率、光合速率和叶面积大小均随生育时间呈现先升高后降低的单峰曲线变化趋势,高、中氮处理(N135、N90)大豆苗期CO2吸收速率明显高于其他处理,但高氮处理(N135)大豆中后期的CO2吸收速率较低;中氮处理(N90)可以使大豆植株对CO2较高的吸收水平维持到中期;低氮处理(N45)大豆后期CO2吸收速率升高;不施氮处理(N0)大豆前期CO2吸收速率最低,后期维持一般水平。随施氮量增加,明显促进了大豆苗期光合速率的提高,不施氮处理在大豆生育中后期(56～73d)有利于光合速率的提高,施入一定氮(N45)更有利于保持大豆后期较高的光合速率。施氮能促进大豆植株前期叶片的生长,使其在整个生育期内都有较大的叶面积;大豆产量随施氮水平增加呈单峰曲线变化趋势,适度施氮有利于产量的提高。     

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 .     

Effect of silicon on the eutectic carbides in as-heated M2 high speed steel

The effect of silicon on the eutectic carbides in as-heated M2 high speed steels is investigated by using optical microscope, scanning electron microscope, energy dispersive spectrometer and X-ray diffraction analysis. The high speed steel ingots with different silicon additions are produced by electroslag remelting process (the mass content of silicon is 0.3%, 0.8%, 1.6% and 2.4%, respectively). The ingots are annealed at 780 ℃ for 10 h and heated at 1 165 ℃ for 2.5 h. The results show that the eutectic carbides distributed in the dendrites with continuous or semi-continuous net-shape in the as-annealed ingots. The eutectic carbides change from lamellar-like M2C to herringbone-like M6C with the increase of silicon content. After 2.5 h heating at 1 165 ℃, the lamellar-like M2C decomposes into granular M6C and MC, and the size of granules in M2 high speed steel ingot with 0.8%Si addition is smaller than that in the 0.3%Si. Whereas herringbone-like M6C is unchanged during heating treatment, and coarse primary blocky carbides which are harmful for properties still exists after the deformation.     

活性炭对提高2,4-D丁酯谷田除草安全性的影响

为了研究2,4-D丁酯作为谷子田化学除草剂的安全性,用活性炭作为保护剂处理谷子种子。采用随机区组设计的方法,通过室内测试和盆栽试验,对谷子的出苗率、株高、地上部分鲜重等形态指标和叶绿素含量、光合速率、蒸腾速率、SOD活性等生理指标进行了测定分析。结果表明:活性炭与硅藻土5∶5拌种(处理4)处理谷种后,可提高2,4-D丁酯对谷子的安全性。     

钛对甜瓜幼苗酸致损伤的影响

４０ｍｇ／ＬＴｉＯ２处理甜瓜幼苗３次，可减轻ｐＨ２．５酸雨对植株的伤害。作者认为，此与ＴｉＯ２能提高甜瓜幼苗光合速率、叶绿素含量，增加过氧化氢酶活性，减少丙二醛含量，降低质膜透性，维持细胞汁ｐＨ稳定性等多重生理作用相关。