镁缺乏和过量胁迫对纽荷尔脐橙叶绿素荧光特性的影响

以2龄枳砧纽荷尔脐橙为材料,研究了镁缺乏和过量胁迫对叶片叶绿素含量和叶绿素荧光特性的影响。结果表明,镁缺乏胁迫导致老叶叶绿素含量显著降低,而新叶叶绿素含量无显著下降;镁过量胁迫显著抑制老叶叶绿素含量的下降,而促进了新叶叶绿素含量的降低。镁缺乏和过量均导致不同叶龄叶片的光化学效率(Fv/Fm)和相对电子传递速率(rETR)降低,但镁缺乏胁迫的影响显著大于镁过量胁迫。缺镁第4个月时,2龄秋梢、1龄春梢、1龄夏梢和晚夏梢叶的Fv/Fm分别比对照低了13.9%、12.6%、2.9%和2.0%,rETRmax值分别比对照低35.7%、56.2%、32.6%和15.2%;而镁过量胁迫叶片的Fv/Fm分别比对照低了0.5%、2.2%、3.4%和1.5%,rETRmax分别为对照的110.1%、68.8%、87.2%和84.5%。缺镁2龄秋梢、1龄春梢和1龄夏梢叶片的非光化学淬灭系数(NPQ)先升后降,热耗散能力显著下降,且显著低于镁过量胁迫。因此,在夏季高光照条件下缺镁胁迫对纽荷尔脐橙光合作用的影响显著,且大于镁过量胁迫,缺镁纽荷尔脐橙叶片易发生光抑制,产生光伤害。     

缺硫对脐橙叶片光合特性和叶绿素荧光参数的影响

采用营养液培养的方法,对缺硫脐橙叶片的光合特性进行了研究。结果表明,在缺硫情况下,脐橙叶片的净光合速率(Pn)、光呼吸速率(Pr)、光合色素含量、可溶性蛋白质含量、初始荧光(Fo)、光化学效率(Fv/Fm)、最大荧光(Fm)和电子传递速率(ETR)显著下降,而光呼吸/光合比(Pr/Pn)显著升高。缺硫脐橙植株的光合能力降低,可能是叶绿体发育不全或特性功能蛋白含量不足所致。     

不同供镁水平对两菊芋品种幼苗生物量、光合和叶绿素荧光特性的影响

采用砂培方式研究了不同供镁水平对"南芋1号(Nanyu No.1)"和"青芋2号(Qingyu No.2)"幼苗生物量、光合特性和叶绿素荧光特性的影响。结果表明:缺镁使菊芋叶片叶绿素含量显著降低,干物质积累减少,净光合速率、蒸腾速率和光合电子传递速率显著下降、CO2同化受抑制,同时Fv/Fm、ΦPSII、qP和qN也显著下降,加重了叶片受到光抑制的程度;随着供镁水平的增加,菊芋的干物质积累,叶绿素含量,光合参数和各系列荧光参数均呈现先增加后降低的趋势;南芋1号和青芋2号在镁离子浓度分别为3和6mmol.L-1,叶片的净光合速率、Fo、Fm、Fo’、Fm’、Fv/Fm、ΦPSII、ETR达到最高值,叶绿素a、b及总叶绿素含量也最多,干物质积累量最大;南芋1号的各系列荧光参数、光合参数、叶绿素含量和干物质积累量均显著高于青芋2号。     

水分胁迫对牛心朴子叶片光合色素及叶绿素荧光的影响

研究了水分胁迫对牛心朴子叶片光合色素及叶绿素荧光动力学参数的影响。结果表明,在长期的水分胁迫中,牛心朴子叶片的叶绿素a(Chl a)、叶绿素b(Chl b)和类胡萝卜素(Car)含量没有下降或下降不明显。直到处理末期才显著下降;叶片叶绿素荧光动力学参数Fo、Fm、Fv、Fv／Fm变化不大,在处理末期各处理Fo降低,轻度、重度水分胁迫的Fm、Fv、Fv／Fm升高。说明K期水分胁迫后牛心朴子的光合功能受到影响,但牛心朴子仍表现出较强的适应干旱的能力。     

模拟秋季酸雨对三角枫叶片光合生理特性的影响

以三角枫幼苗为材料,采用盆栽方法,研究了pH 5.6、pH 4.0、pH 3.0和pH 2.0酸度模拟酸雨胁迫对三角枫叶片光合生理特性的影响,以探讨酸雨胁迫下三角枫的光合生理响应机制。结果显示:(1)随着酸雨浓度的增加和胁迫时间的延长,三角枫叶片相对叶绿素含量下降幅度逐步增大;叶片丙二醛含量呈逐渐上升的趋势,且各处理均显著高于对照;叶片质膜透性和脯氨酸含量均呈先升高后降低的趋势,且pH 2.0处理的叶片质膜透性在试验20d时迅速增大,升高幅度最大(146.3%)。(2)叶片净光合速率、蒸腾速率、水分利用效率、表观光能利用效率以及表观CO2利用效率在胁迫下也均呈显著下降趋势,且以pH 3.0和pH 2.0处理降幅最大。研究表明,pH 4.0的模拟酸雨对三角枫叶片的光合生理指标无显著影响,而pH≤3.0的强酸雨胁迫使三角枫叶片叶绿素含量显著下降、膜保护系统受损、光合作用效率显著下降;三角枫能适应弱酸雨(pH≥4.0)环境,可作为酸雨地区的园林绿化树种。     

不同纬度产地纽荷尔脐橙果实品质状况初步研究

以纽荷尔脐橙为试材,分析了我国甜橙优势区域内不同纬度地区纽荷尔脐橙果实主要的品质指标。结果表明,纽荷尔脐橙果实的多数品质指标随纬度的变化呈现有规律的变化;线性回归分析结果显示,纽荷尔脐橙果实几项品质指标与纬度的相关性为:可溶性固形物含量呈显著线性正相关,可滴定酸含量呈极显著线性正相关,固酸比呈极显著线性负相关,果皮黄色度和着色强度呈极显著线性负相关,色调角呈显著线性负相关,VitC含量与纬度的线性关系接近显著程度。     

外源5-氨基乙酰丙酸对盐胁迫下黄连幼苗光合参数及其叶绿素荧光特性的影响

该实验以2年生黄连幼苗为材料,在100mmol·L-1的NaCl模拟盐胁迫条件下,经不同浓度的外源5-氨基乙酰丙酸(ALA)处理后,测定黄连幼苗光合色素含量、叶绿素荧光参数及气体交换参数等光合生理指标的变化,探寻提高黄连幼苗在盐胁迫条件下抗性能力的途径。结果显示:(1)NaCl胁迫下黄连幼苗的光合生理受到显著抑制,在经过不同浓度的ALA处理后,显著提高了叶绿素a、叶绿素b、总叶绿素和类胡萝卜素等光合色素的含量。(2)盐胁迫下,黄连植株的的净光合速率(Pn)、气孔导度(Gs)及叶片蒸腾速率(Tr)均发生下降,并且随着胁迫时间和胁迫浓度的增加下降幅度逐渐增大,胞间CO2浓度(Ci)则呈上升趋势,说明盐胁迫下黄连净光合速率降低的主要影响因素是非气孔因素。(3)用ALA处理后,黄连的Pn、Gs及Tr均有不同程度的提高,Ci也有不同程度的降低,并且不同的浓度梯度存在着显著的效果差异。(4)ALA处理还提高了最大荧光(Fm,1.234)、最大光化学效率(Fv/Fm,0.849)、PSⅡ有效光化学效率(Fv′/Fm′,0.685)、PSⅡ实际光化学效率(ΦPSⅡ,0.545)和光化学淬灭系数(qP,0.872)的水平,有效降低了初始荧光(F0,0.211)和非光化学淬灭系数(NPQ,0.251)的水平。研究表明,外源ALA通过提高黄连幼苗叶片的光合色素含量,减少过剩激发能的耗散,提高光合电子传递效率,有效缓解了盐胁迫对黄连叶片PSⅡ的伤害,提高了植株的抗盐能力。     

水分胁迫对冬小麦光合特性及产量的影响

对不同水分条件下小麦叶片叶绿素含量、叶绿素荧光参数及光合速率的变化进行了研究．结果表明,随着胁迫的加剧．其叶绿素含量降低,且叶绿素a的含量下降比叶绿素b的含量要快。住不同水分条件下,叶片叶绿素含量及光合速率随生育进程的变化趋势基本一致．拔节期到抽穗期迅速上升,灌浆期后迅速下降,且叶绿素含量与光合速率呈显著的正相关。在水分胁迫下旗叶的T12值减少．旗叶光系统Ⅱ(PSⅡ)原初光能转化效率(Fv／Fm)和潜在活性(Fv／Fo)降低．胁迫程度越大其值降低幅度越大,轻度胁迫与对照相比其值降低幅度小。而重度胁迫其值急剧下降,这些值的降低,导致了光合作用的潜在活力降低,影响了光合电子的传递和CO2同化的正常进行,最终导致产量降低。     

供镁水平对油桐幼苗生长及光合特性的影响

采用营养液砂培试验,研究不同供镁水平对油桐幼苗生长、光合特性及叶绿素荧光参数等的影响。结果表明,低镁浓度(Mg2+2 mmol·L-1)显著抑制了油桐的生长,叶绿素含量、Ru BP羧化酶及PEPC活性、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、气孔限制值(Ls)、水分利用效率(WUE)、最大光化学效率(Fv/Fm)、实际光化学量子效率(ΦPSII)、PSII的潜在活性(Fv/Fo)及光化学淬灭系数(q P)显著下降(P0.05),胞间CO2浓度(Ci)、初始荧光(Fo)、非光化学淬灭系数(NPQ)有所升高;高镁浓度(Mg2+4 mmol·L-1)也抑制了油桐幼苗的生长,导致叶片叶绿素含量、Ru BP羧化酶活性、Pn、Gs、Fv/Fm、Fv/Fo及q P均下降(P0.05);随着供镁水平的增加,油桐的生长量、叶绿素含量、Ru BP羧化酶及PEPC活性、Pn呈先增加后降低的趋势;当镁离子浓度为2~4 mmol·L-1时,有利于油桐幼苗正常生长,缺镁胁迫下油桐光合速率的下降主要是由光合机构活性降低的非气孔因素引起的。     

盐胁迫对鸡爪槭幼苗生长及其叶绿素荧光参数的影响

以鸡爪槭幼苗为材料,采用盆栽方法,研究了不同盐浓度[0.042%(对照)、0.2%、0.4%和0.6%]对鸡爪槭幼苗生长的伤害和叶绿素荧光参数的影响。结果显示:当土壤NaCl含量为0.2%、0.4%和0.6%时,鸡爪槭幼苗分别表现为轻度、中度和重度盐害;叶片含水量、叶绿素a和b及叶绿素总含量均随盐浓度的增加而显著下降,花色素苷含量则表现为随盐浓度的增大而显著上升,分别比对照高出48.7%、280.3%和382.7%;叶片叶绿素荧光参数PSⅡ潜在活性(Fv/Fo)、潜在量子效率(Fv/Fm)、光化学量子产量(Yield)、光合电子传递速率(ETR)、实际光化学效率(ΦPSⅡ)和光化学猝灭系数(qP)均随着盐浓度的增大呈显著下降趋势,但非光化学猝灭系数(NPQ)在低盐胁迫时则较对照显著提高,0.2%NaCl处理时比对照显著增加33.3%,而高盐胁迫下则显著下降。研究表明,盐胁迫显著抑制了鸡爪槭幼苗叶片叶绿素合成和光合作用进行,而幼苗叶片在低盐胁迫下则可能通过增加PSⅡ反应中心非辐射热能量耗散来保护光合机构不受损害,从而表现出一定的耐盐胁迫能力。     

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.     

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.     

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.     

The mechanism of hatching of eggs of Haemonchus contortus

Fluid collected from hatching eggs of Haemonchus contortus contained a lipase which hydrolysed 2-naphthyl laurate (about 0·7 μmol naphthol freed /h/10⁶ eggs). The fluid also hydrolysed l-leucinamide (about 2·3 μmol leucine freed/h/10⁶ eggs). The fluid when added to normal or heated eggs caused ‘hatching’. ‘Hatching’ also occurred in exsheathing fluid from infective juveniles and in a preparation of pancreatic lipase containing leucine aminopeptidase. A purified mammalian leucine aminopeptidase in combination with several different lipases did not attack egg shells.The ‘spontaneous’ hatching of eggs of H. contortus was strongly inhibited by 1,10-phenanthroline, 10^?3M, and this inhibition was reversed by Zn²⁺. However, the inhibition of ‘hatching’ of eggs in externally applied hatching fluid, or the hydrolysis of leucinamide in hatching fluid was generally less marked.     

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.