杂种杨无性系的光系统Ⅱ放氧活性、光合色素及叶绿体超微结构对光胁迫的响应

 用氧电极仪、红外CO2气体分析仪及叶绿素荧光仪,结合透射电镜技术对几个杂种杨无性系在光胁迫下的光系统Ⅱ活性、光合色素及叶绿体超微结构进行了测定。随着预处理光强的增加,各无性系叶片的净光合速率和光系统Ⅱ放氧活性明显下降。二倍体无性系B11的光系统Ⅱ最大光化学效率（Fv/Fm）及实际光化学效率［(Fm′-F)/Fm′］高于两个三倍体无性系B346和B342。强光下三倍体无性系B346的非光化学淬灭远高于B342和二倍体无性系B11。叶绿素含量和光合速率没有明显的线性关系,叶绿素a/b含量在自然光胁迫下存在季节变化,受强光胁迫2个三倍体无性系的叶绿素a/b增大。预处理光强PFD超过3 000 μmol photons·m-2·s-1,各无性系的基粒类囊体片层结构遭到破坏,但二倍体无性系的类囊体片层结构受破坏程度较三倍体无性系轻。叶绿体蛋白合成抑制剂（硫酸链霉素,SM）可加剧叶绿体超微结构的破坏。     

低氧胁迫下黄瓜植株热耗散途径

采用营养液栽培,研究了低氧(营养液溶氧浓度为0.9～1.1 mg·L-1)胁迫下黄瓜幼苗光合作用热耗散与叶黄素循环的关系.结果表明:低氧胁迫下,黄瓜叶片PSⅡ的实际光化学效率(φPSⅡ)、饱和光强下的净光合速率(Pn)、表观量子效率(AQY)和PSⅡ的最大光化学效率(Fv/Fm)均显著降低,表明黄瓜植株的光合作用受到了光抑制;同时,光化学猝灭系数(qp)降低,而热耗散(NPQ)和天线耗散能量(D)的比值显著升高,说明黄瓜叶片热耗散增强;NPQ与叶黄素脱环氧化状态(DEPS)呈显著正相关,且两者均被抗坏血酸(AsA)所促进,被二硫苏糖醇(DTT)所抑制,说明低氧胁迫下,叶黄素循环是黄瓜植株光合作用热耗散的主要途径.     

通过快速荧光动力学曲线探测白黄瓜光系统Ⅱ的热激胁迫效应

以耐热性较强的短粗型白黄瓜和长棒型白黄瓜为试材,并以耐热性较差的‘新泰密刺'和耐热性较强的‘津春4号'为对照品种,经热激胁迫后采用植物效率仪PEA测试,进行光系统Ⅱ(PSⅡ)快速叶绿素荧光诱导动力学分析(JIP-test)及其热稳定性的热力学分析.随着热激胁迫温度的升高(在30～57 ℃下5 min),表现为PSⅡ的最大光化学效率Fv/Fm、单位面积的光合机构含有的反应中心数目RC/CSo、放氧复合体活性ρk呈"S"型下降趋势;单位反应中心以热能形式耗散的能量DIo/RC呈"S"型上升趋势.综合分析反映出热激胁迫下PSⅡ反应中心的可逆失活、放氧复合体(OEC)的钝化和热耗散的三重机制在保护PSⅡ防止光抑制中起到重要作用.热激胁迫温度超过30 ℃时ρk就开始下降;超过40 ℃时RC/CSo开始下降;超过44 ℃以上,PSⅡ热耗散能力DIo/RC才表现出增加;超过51℃时,会加重耐热性较差的新泰密刺品种PSⅡ热耗散机构对PSⅡ保护的负担.通过标准状态变性自由能变ΔGD计算的变性中点温度Tm表明,PSⅡ蛋白复合体的热稳定性优于PSⅡ反应中心复合体热的稳定性和放氧复合体(OEC)的热稳定性.对于Fv/Fm、RC/CSo、和ρk的Tm均呈现出津春4号耐热性较强,新泰密刺耐热性较差,长棒型白黄瓜和短粗型白黄瓜耐热性居中.     

外源Ca2＋对高温强光胁迫下灌浆期小麦叶片光合机构运转的影响

灌浆期叶面喷施10mmol·L-1 CaCl2对高温强光胁迫下小麦叶片光合电子传递、放氧速率、叶绿素荧光参数和D1蛋白的影响结果表明,Ca2＋预处理可保护D1蛋白,削弱其降解,提高光系统I（PSI）和光系统Ⅱ（PSⅡ）子传递速率、全链电子传递速率、净光合速率（Pn）、PSII最大光化学效率（Fv/Fm）、PSII实际光化学效率（ΦPSⅡ）和光化学猝灭（qp）,维持较低的Fo,最终导致小麦适应高温强光的能力提高。     

毕氏海蓬子类囊体膜与卵磷脂重组脂质体的耐热性研究

采用卵磷脂(PC)构建脂质体,然后将毕氏海蓬子类囊体膜蛋白复合物重组到脂质体中.分析不同温度(25℃、35℃、45℃和55℃)处理后蛋白脂质体的电子传递活性、吸收光谱和荧光光谱的变化,以探讨膜脂与膜蛋白在高温胁迫下的交互作用.结果显示:蛋白脂质体光系统Ⅱ(PSⅡ)的放氧活性和光系统Ⅰ(PSⅠ)的耗氧活性随着PC比例的提高而增加,在PC与类囊体膜比例为4∶1(Lipid∶Chl,w/w)时达到最高,同时蛋白脂质体的吸收光谱和荧光光谱也呈上升趋势;在PC与类囊体膜重组比例为4∶1条件下,高温处理后的蛋白脂质体的PSⅡ放氧活性和PSⅠ耗氧活性显著大于未经重组的,其吸收光谱和荧光光谱峰值下降幅度低于未经重组的,且峰位基本没有变化.研究表明,PC可能通过增加结合天线的大小来促进蛋白脂质体对光能的吸收和能量从外周天线到PSⅡ和PSⅠ核心复合物的传递;在脂质体中,PC与类囊体膜的交互作用提高了PSⅡ和PSⅠ在高温胁迫下的光化学效率,增强了PSⅡ和PSⅠ的耐热性.     

铅胁迫对玉米幼苗叶片光系统功能及光合作用的影响

通过同时测定玉米叶片的叶绿素荧光快速诱导动力学曲线和对820 nm光的吸收、分析叶片的气体交换过程以及叶绿体活性氧清除关键酶的活性,研究了不同浓度的铅(Pb)胁迫对玉米光系统Ⅰ(PSⅠ)、光系统Ⅱ(PSⅡ)的光化学活性和光合作用的影响,并分析了Pb胁迫下两个光系统的相互关系.结果表明:铅胁迫显著抑制了玉米地上部分和地下部分的生长、降低了叶片光合色素含量、并通过非气孔因素限制了光合作用、导致过剩激发能的增加;铅胁迫显著抑制了超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)的活性、伤害了PSII反应中心、PSII的受体侧和供体侧(放氧复合体)以及PSI光化学活性.     

夜间低温后日间光照对海桐和榕树叶片的光抑制以及光系统Ⅱ功能的影响

夜间低温导致海桐和榕树叶片光系统Ⅱ(PSⅡ)最大光化学效率(Fv/Fm)、PSⅡ光合电子传递量子效率(φPSⅡ)、天线转化效率(F'v'/Fm')、非光化学猝灭系数(NPQ)降低,其后日间光照先引起海桐叶片Fv//Fm、ΦPSⅡ、F'v'/Fm'稍微降低,其后又逐渐得到恢复,但NPQ却表现出相反趋势;夜间低温及随后的日间光照并未对海桐叶片光化学猝灭系数(qP)和初始荧光强度(Fo)产生影响.夜间低温后日间光照进一步引起榕树叶片Fv/Fm、ΦPSⅡ、Fv'/F'm、qp、NPQ下降,在午后光照减弱后仍不能得到恢复.     

低温胁迫下交替呼吸途径对当归幼苗叶绿素荧光活性的影响

以岷当归幼苗为材料,通过温室盆栽试验研究了在低温(4℃和-7℃)胁迫下交替呼吸途径对当归幼苗叶片叶绿素含量和荧光特性的影响,探讨交替呼吸途径在当归响应低温逆境过程中的作用。结果表明,随着胁迫温度的降低和处理时间的延长,当归叶片的叶绿素含量、实际光化学效率[Y(Ⅱ)]、光合电子传递速率(ETR)及光化学淬灭系数(qL)逐渐降低,而非光化学猝灭系数(NPQ)升高;同时,低温胁迫也导致当归幼苗叶片交替呼吸容量显著升高;在低温胁迫下,经交替呼吸途径抑制剂[1 mmol·L~(-1)的水杨基氧肟酸(SHAM)]预处理的当归幼苗叶片叶绿素含量、Y(Ⅱ)、ETR及qL进一步显著下降,而NPQ进一步显著升高,且温度越低升降幅度越大。研究发现,低温胁迫对当归幼苗叶片叶绿素的合成以及PSⅡ的光化学性能产生了显著抑制,低温胁迫下交替呼吸途径对当归幼苗叶绿素合成以及PSⅡ的光化学性能具有一定的保护作用。     

镧胁迫下外源H2O2对裸燕麦幼苗叶绿素荧光参数和光合碳同化酶活性的影响

稀土污染已成为制约农业发展的一种重要因素,为探讨外源过氧化氢(H_2O_2)缓解裸燕麦镧(La)胁迫伤害的光合生理机制,以‘白燕7号’裸燕麦幼苗为材料,采用砂培方法,研究了5 mmol/L H_2O_2喷施预处理对1.20 mmol/L La~(3+)胁迫下裸燕麦幼苗生长、叶片叶绿素荧光参数和碳同化关键酶活性的影响。结果表明:La胁迫下,H_2O_2预处理的裸燕麦幼苗根长、株高和生长量的降幅及叶片叶黄素循环脱环氧化状态(A+Z)/(V+A+Z)显著下降,PSⅡ最大光化学效率(F_v/F_m)、实际光化学效率(Φ_(PSⅡ))、光化学猝灭系数(qP)和吸收光能用于光化学反应的份额(P)显著提高,PSⅡ非光化学猝灭系数(NPQ)、调节性能量耗散Y(NPQ)、非调节性能量耗散Y(NO)、吸收光能用于天线热耗散的份额(D)、PSⅡ反应中心非光化学耗散的份额(E_x)和双光系统间激发能分配不平衡偏离系数(β/α-1)明显降低,同时1, 5-二磷酸核酮糖羧化酶(Rubisco)、1, 7-二磷酸景天庚酮糖酯酶(SBPase)和1, 6-二磷酸果糖醛缩酶(FBAase)活性显著提高,但转酮醇酶(TKase)活性无显著变化。表明外源H_2O_2能够通过提高PSⅡ光化学效率和碳同化关键酶活性而非依赖叶黄素循环的热耗散来减轻La胁迫导致的光抑制,从而缓解La胁迫幼苗生长的受抑程度,增强裸燕麦对La胁迫的适应性。     

Cd2+胁迫对银芽柳PSⅡ叶绿素荧光光响应曲线的影响

以盆栽银芽柳为材料,利用MINI-IMAGING-PAM荧光成像测定系统,研究了Cd²⁺胁迫下叶片叶绿素荧光参数的变化及其光响应曲线。结果表明,初始荧光Fo与最大荧光Fm随着Cd²⁺浓度的增大而呈现先升后降的趋势,Fo与Fm在200 mg/LCd²⁺处理4周时达到最高值,400 mg/LCd²⁺处理则显著下降;PSⅡ最大光化学效率(Fv/Fm)与PSⅡ潜在光化学效率(Fv/Fo)显著受 Cd²⁺胁迫抑制,但随Cd²⁺浓度的增加呈先降后升的变化趋势。Cd²⁺胁迫下各叶绿素荧光参数的光响应结果表明,PSⅡ实际光量子效率Y(Ⅱ)、荧光淬灭系数(qP)随光化光强度的增加呈下降趋势,而同光强下高浓度Cd²⁺ 使Y(Ⅱ)与(qP) 显著降低;PSⅡ调节性能量耗散的量子产额Y(NPQ)、非光化学淬灭系数(qN)与表观电子传递速率(ETR)则随着光强增加呈上升趋势,同光强下高浓度Cd²⁺处理显著提高Y(NPQ)、qN 与ETR。Cd²⁺胁迫下,PSⅡ非调节性能量耗散的量子产额Y(NO)稳定在较低水平,同光强下Y(NO)随Cd²⁺浓度增加略有提高。说明,银芽柳通过调节PSⅡ反应中心开放程度与活性,对Cd²⁺胁迫表现出较强的耐性,高浓度Cd²⁺胁迫导致PSⅡ反应中心关闭或不可逆失活,表现出光抑制。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.