氮素形态对番茄根系液泡膜焦磷酸酶活性的影响

采用超速梯度离心提取液泡膜微囊,研究硝态氮和铵态氮供应情况下番茄（Lycopersicon esculentum L.)根系液泡膜焦磷酸酶活性的变化。结果表明：供应铵态氮番茄根系专一性液泡膜焦磷酸酶活性比供应硝态氮的高37．7％;供应铵态氮根系液泡膜焦磷酸酶转运质子活力也明显高于供应硝态氮根系。Western blot结果表明,供应铵态氮根系液泡膜焦磷酸酶蛋白表达量也明显增加。     

Na~ ,K~ 和ABA对盐胁迫大麦根液泡膜ATPase活性的影响

许多植物液泡膜ATPaso活性与植物抗盐性有关(Bremberger等1988,Matsumoto和Chung 1988,Gabarino和Dupont 1988)。当植物生长在高浓度NaCl环境中时,液泡膜上Na~ /K~ 交换对维持细胞质中高K~ /Na~ 起重要作用(Jeschke     

盐胁迫对豌豆根液泡膜H^＋—ATPase活性及含量的影响

为了阐明液泡膜H^ -ATPase在盐胁迫下的作用和适应性调节机制,对豌豆（Pisum sativum L.）植株进行不同盐浓度和不同盐胁迫时间（1－3d）的处理后,分别测定液泡膜H^ -ATPase的H^ 转运活性、水解性和蛋白含量（A亚基）的变化。结果表明,100mmol/L和200mmol/L NaCl 处理1dH^ -ATPase的水解活性没有变化,而250mmol/L NaCl处理1d引起水解活性降低约25％。100mmol/L NaCl处理2d内水解活性没有变化,而第3天活性下降约20％。但是上述盐胁迫均能提高液泡膜H^ -ATPase的质子转运活性,说明盐胁迫后H^ -ATPase的水解活性和质子转运活性的变化不成比例,盐胁迫可能导致偶联比率的改变。Western blot研究发现,上述盐胁迫对液泡膜H^ -ATPase（A亚基）的含量基本无影响,仅100mmol/L NaCl处理3d后A亚基的量略有下降,这些结果证明,盐胁迫能刺激提高豌豆根液泡膜H^ -ATPase的H^ 泵效率,且泵效率的提高是源于偶联比率的改变,而不是由于ATP水解活性的提高和蛋白含量的增加。     

Effects of Salt Stress on the Activity and the Amount of Tonoplast H+-ATPase from Pea Roots

To study the function and adaptive mechanism of tonoplast H+ATPase under salt stress, pea ( Pisum sativum L.) seedlings were treated with different concentrations of salt （100-250 mmol/L NaCl） and with 100 mmol/L NaCl for different days (1-3 d). The ATP hydrolytic activity and the proton transport activity and the changes of the amount of tonoplast H+ ATPase (subunit A) were measured. ATP hydrolytic activity of H+ATPase prepared from plants treated with 250 mmol/L NaCl was reduced by about 25% compared to that of control plants, but that of stressed plants treated with 100 mmol/L and 200 mmol/L NaCl was unchanged. The activity from plants treated with 100 mmol/L NaCl for up to 3 d was lower than that of control plants by 20%. But the proton transport activity was increased under the same salt stresses as above. These results showed that the changes of the hydrolytic activity and the proton transport activity were not in proportion and salt stress may cause the change of the coupling ratio of H+ transport activity to ATP hydrolysis. The protein amount kept unchanged and reduced a little only when pea was treated with 100 mmol/L NaCl for 3 d. These results indicated that salinity stimulated the increase of the pump efficiency of the V-ATPase from pea roots, which was due to the change of the coupling ratio, but not due to the increase of ATP hydrolysis and the amount of V-ATPase.     

NaCl胁迫对高粱根、叶鞘和叶片液泡膜ATP酶和焦磷酸酶活性的影响

NaCl胁迫初期 ,Na 主要在根和叶鞘中积累。相应地 ,根和叶鞘液泡膜ATP酶和焦磷酸酶水解活性、依赖ATP和PPi的质子泵活性及Na /H 逆向转运活性均明显增加 ,根和叶鞘的生长没有受到抑制。NaCl胁迫后期 ,Na 开始向地上部分运输并在叶片中积累。此时 ,叶片液泡膜质子泵和Na /H 逆向转运活性开始增加 ,根和叶鞘的Na/K比增加 ,其液泡膜ATP酶和焦磷酸酶水解活性、质子泵活性和Na /H 逆向转运活性下降。相应地 ,根和叶鞘的生长也下降。当保温介质中Na/K比超过 1时 ,液泡膜微囊ATP酶和焦磷酸酶活性均随Na/K比的增加而下降。表明非盐生植物液泡膜质子泵在盐胁迫的初期对Na 在液泡内的积累及其耐盐性起重要作用     

Two Proton Pumps Operate in Parallel Across the Tonoplast of Vacuoles Isolated from Suspension Cells of Chenopodium rubrum L.*

The kinetics of vacuolar acidification upon addition of ATP and/or pyrophosphate (PPi) has been assayed on single immobilized vacuoles by computer-aided microfluorimetry of 9-aminoacridine, and by acridine orange absorption photometry on vacuole suspensions isolated from green suspension cells of Chenopodium rubrum L. Two proton pumps at the tonoplast, an ATPase and a pyrophosphatase (PPase), operate in parallel to acidify the vacuole with different contributions adding up to a transtonoplast Δ pH of 2.6 pH units at external pH 7.2. The saturable components of proton pumping reach half maximal velocity with 0.32 ± 0.06 mM ATP and 23 ± 2.5 μM PPi, respectively. At saturating substrate concentrations, ATPase and PPase hydrolyse ATP and PPi, respectively, at a ratio of 2.3. The same ratio holds for the corresponding proton fluxes maintaining a given steady-state vacuolar pH. We conclude that both pumps operate at the same stoichiometry.     

NaCl胁迫下大麦根液泡膜H^＋—ATPase活性、离子吸收与钙的关系

NaCl胁迫 2d ,耐盐大麦 (HordeumvulgareL .cv) (“滩引 2号”)根系液泡膜H _ATPase活性增强 ,H _PPase活性下降。以质膜Ca2 通道抑制剂La3 (1mmol/L)或Ca2 螯合剂EGTA (5mmol/L)处理大麦幼苗 ,抑制了NaCl诱导的液泡膜H _ATPase活性的增强 ,但提高了H _PPase活性 ;用CaM拮抗剂三氟拉嗪 (TFP ,2 0 μmol/L)处理 ,也抑制了液泡膜H _ATPase活性的增强。NaCl胁迫下 ,外加La3 ,TFP或La3 TFP处理 ,使Na 吸收增加 ,K 和Ca2 吸收降低。结果表明 ,NaCl胁迫下 ,液泡膜H _ATPase活性提高和离子吸收的变化可能与Ca_CaM系统有关。     

植物焦磷酸酶(PPase)的研究进展

植物焦磷酸酶(PPase)可分为存在于细胞质中可溶性的无机焦磷酸酶和与膜结合的不可溶性焦磷酸酶.后者不仅能水解焦磷酸,同时还具有质子泵的功能.橡胶树乳管中与黄色体膜结合的不可溶性焦磷酸酶,是调控橡胶生物合成的一个必不可少的酶.对植物焦磷酸酶的结构及其功能和分子生物学研究的进展进行了综合论述,并着重阐述了焦磷酸酶在橡胶树橡胶生物合成中的作用.     

The Effect of Pyrophosphate Analogues on the Activity of the Inorganic Pyrophosphatase from Escherichia coli

The effect of inorganic pyrophosphate analogues on the enzymic activity of inorganic pyrophosphatase from E. coli was studied. Hypophosphoric and diphosphonic acids were shown to inhibit inorganic pyrophosphatase, whereas pyrophosphorous acid exerts almost no effect on the hydrolysis of inorganic pyrophosphate.     

NaCl胁迫下大麦根液泡膜H+-ATPase活性、离子吸收与钙的关系

NaCl胁迫2 d,耐盐大麦(Hordeum vulgare L.cv) ("滩引2号")根系液泡膜H+-ATPase活性增强,H+-PPase活性下降.以质膜Ca2+通道抑制剂La3+ (1 mmol/L)或Ca2+螯合剂EGTA (5 mmol/L)处理大麦幼苗,抑制了NaCl诱导的液泡膜H+-ATPase活性的增强,但提高了H+-PPase活性;用CaM拮抗剂三氟拉嗪(TFP,20 μmol/L)处理,也抑制了液泡膜H+-ATPase活性的增强.NaCl胁迫下,外加La3+,TFP或La3++TFP处理,使Na+吸收增加,K+和Ca2+吸收降低.结果表明,NaCl胁迫下,液泡膜H+-ATPase活性提高和离子吸收的变化可能与Ca-CaM系统有关.     

NaCl胁迫下大麦根系液泡膜H+-ATP酶活性受ATP和焦磷酸含量的调节

选用两个耐盐性强弱不同的大麦(Hordeumvulgare L.)品种,研究了NaCl胁迫下其幼苗根中ATP和焦磷酸(PPi)含量的变化以及PPi对液泡膜H -ATP酶活性的影响.结果表明:在含NaCl 200mmol/L的1/2 Hoagland溶液中处理2 d,耐盐品种(滩引2号)根中液泡膜H -ATP酶活性增加,然后逐渐下降,而H -PPi酶活性在NaCl处理9 d中'直下降.盐敏感品种(科品7号)在NaCl胁迫下根中H -ATP酶和H -PPi酶活性都下降(图1).与对照相比较,NaCl胁迫下耐盐品种根中ATP含量2 d时增加,4 d后下降;盐敏感品种根中ATP积累受NaCl胁迫的抑制(图2).NaCl胁迫下,两品种的PPi含量皆略有增加(图3).PPi对液泡膜H -ATP酶活性有竞争性抑制作用(图4).结果表明:ATP积累是NaCl胁迫下液泡膜H -ATP酶活性增加的原因之一,NaCl胁迫下大麦品种根中ATP含量下降和PPi对液泡膜H -ATP酶的抑制使该酶活性下降.     

Properties of proton and sugar transport at the tonoplast of tomato (Lycopersicon esculentum) fruit

Tonoplast vesicles were isolated from tomato (Lycopersicon esculentum Mill.) fruit pericarp and purified on a discontinuous sucrose gradient. ATPase activity was inhibited by nitrate and bafilomycin A₁ but was insensitive to vanadate and azide. PPase hydrolytic activity was inhibited by NaF but was insensitive to nitrate, bafilomycin A₁ vanadate and azide. Kimetic studies of PPase activity gave an apparent K_m, for PP₃ of 18 μM. Identical distributions of bafilomycin- and NO₃-sensitive ATPase activities within continuous sucrose density gradients, confirmed that bafilomycin-sensitive ATPase activity is a suitable marker for the tonoplast. By comparing the distribution of bafilomycin-sensitive ATPase activity with that of PPase activity, it was possible to locate the PPase enzyme exclusively at the tonoplast. The apparent density of the tonoplast did not change during fruit development. Measurements of tonoplast PPase and ATPase activities during fruit development over a 35-day period revealed an 80% reduction in PPase specific activity and a small decrease in ATPase specific activity. ATP- and PP₁-dependent ΔpH generation was measured by the quenching of quinacrine fluorescence in tonoplast vesicles prepared on a discontinuous Dextran gradient. No H⁺ efflux was detected on the addition of sucrose to energized vesicles. Therefore a H⁺/sucrose antiport may not be the mechanism of sucrose uptake at the tomato fruit tonoplast. Similar results were obtained with glucose, fructose and sorbitol. The lack of ATP (or PP₁) stimulation of [¹⁴C]-sucrose uptake also suggested that an antiport was not involved. Initial uptake rates of radiolabelled glucose and fructose were almost double that for sucrose. The inhibition of hexose uptake by p-chloromercuribenzene sulphonate (PCMBS) implicated the involvement of a carrier. Therefore storage of hexose in the tomato fruit vacuole and maintenance of a downhill sucrose concentration gradient into sink cells is likely to be regulated by the activity of sucrose metabolizing enzymes, rather than by energy-requiring uptake mechanisms at the tonoplast.     

菠萝叶片绿色组织与贮水组织液泡膜ATPase和焦磷酸酶特性

研究了景天酸代谢 (CAM)植物菠萝叶片绿色组织与贮水组织液泡膜ATPase和焦磷酸酶 (PPase)特性。绿色组织有较高的ATPase和PPase活力。贮水组织 (绿色组织 )ATPase和PPase活力的最佳温度分别为 43和 49℃ (3 7和 46℃ )。当温度小于最佳温度时 ,ATPase和PPase活力随着温度的上升而上升 ;而当温度大于最佳温度时 ,ATPase和PPase活力随着温度的上升而下降。在 (1 0～ 46℃ ) 1 0～3 7℃的温度范围 ,绿色组织 (PPase)ATPase活力随着温度的上升而上升的速度大于贮水组织中(PPase)ATPase活力上升的速度 ,绿色组织有 (相对 )较高的ATPase和PPase活力 ;但在 (49～ 6 1℃ )43～ 5 5℃的温度范围 ,贮水组织中 (PPase)ATPase活力随着温度的上升而下降的速度小于绿色组织中(PPase)ATPase活力下降的速度 ,贮水组织有相对较高的ATPase和PPase活力。此外 ,贮水组织中这两种酶活力的热稳定性强于绿色组织中这两种酶活力的热稳定性。对这两种酶活力的最佳 pH和底物依赖性也进行了研究     

磷饥饿下番茄幼苗根系液泡膜H+-ATPase活性的适应性变化

以‘世纪星’番茄为材料。研究了磷饥饿下番茄幼苗的生长状况及其根部液泡膜H^＋-ATPase活性的适应性变化。结果表明：磷饥饿下番茄幼苗的平均高度均低于对照苗,而主根长度均显著长于对照。磷饥饿提高了番茄幼苗根部液泡膜H^＋-ATPase的水解活性,随着磷胁迫时间的延长,该酶的活性逐渐增大,在磷饥饿7d时达到最大,后又略有降低;而对照番茄幼苗根部该酶的活性变化很小。动力学分析表明：磷饥饿使番茄幼苗根部液泡膜H^＋-ATPase的Km值明显降低,但对该酶的Kmax影响不大。这说明磷饥饿提高了该酶对其底物的亲和力。此外,磷饥饿并不改变液泡膜H^＋-ATPase酶的最适pH值（仍为7．5）。     

Membrane Particles,Proteins and ATPase Activity of Tonoplast Vesicles of Mesembryanthemum crystallinum in the C-3 and CAM State*

Dimensions and area densities of membrane particles were studied by electron microscopy of replicas of freeze-fractured suspensions of tonoplast vesicles of Mesembryanthemum crystallinum L. in the C-3 state and after induction of crassulacean acid metabolism (CAM) by salinity. The results are compared with the relative contribution of tonoplast-ATPase protein to total membrane protein obtained from integration of elution profiles in size-exclusion chromatography. Coverage of tonoplast area by globular membrane particles was 20% and 36 % and ATPase in relation to total membrane protein was 33 % and 35 % in C-3 and CAM M. crystallinum, respectively. Thus, by order of magnitude, it is most likely that the particles represent the ATPase. In Kalanchoë daigremontiana Hamet et Perrier de la Bâthie the ATPase also constituted 36% of total tonoplast protein. Induction of CAM in M. crystallinum was associated with an increase in specific ATPase activity of the tonoplast and an increase of the size and area coverage of tonoplast particles, whereas the relative contribution of ATPase protein to total tonoplast protein and the molecular mass of the ATPase holoenzyme, as seen in size-exclusion chromatography, remained almost unchanged.     

等渗盐胁迫对番茄抗氧化酶和ATP酶及焦磷酸酶活性的影响

用Ca(NO3)2 80 mmol/L和NaCl 120 mmol/L等渗溶液处理番茄幼苗后,细胞质和叶绿体中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性升高,并且NaCl胁迫的作用明显高于Ca(NO3)2胁迫.Ca(NO3)2处理提高了线粒体中SOD、CAT、APX的活性,而NaCl处理降低了它们的活性.根系质膜H -ATPase、液泡膜H -ATPase、焦磷酸酶(H -PPase)的活性和叶片丙二醛(MDA)及脯氨酸含量在两种盐胁迫后明显增加.NaCl处理对植株生长的抑制程度明显高于Ca(NO3)2处理.     

不同光强下氮素形态对番茄谷氨酰胺合成酶和光呼吸的影响

强光(800μmol·m-2·s-1)下供应铵态氮的番茄植株与供应硝态氮的相比,其生长受到显著抑制,谷氨酰胺合成酶(GS)活性和光呼吸速率显著下降,同时净光合速率(Pn)和叶绿素荧光参数(Fv/Fm、Fv/F.)值下降;而弱光(200μmol·m-2·s-1)下供应铵态氮与硝态氮植株之间的这些参数差异不显著.     

NaCl 胁迫对小麦抗盐突变体根液泡膜H+-ATP酶 和H+-PP酶活性的影响

随着盐胁迫强度（ ＮａＣｌ ０ ～１５０ｍ ｍｏｌ／Ｌ） 和时间（０ ～７２ ｈ） 的增加,小麦抗盐突变体根液泡膜Ｈ＋ＡＴＰ 酶和Ｈ＋ＰＰ 酶活性显著增加,虽然野生型酶活性在盐胁迫下也有增加,但其增加的幅度显著低于突变体,Ｈ＋ＰＰ酶活性的差异更为显著。Ｈ＋ＡＴＰ酶和Ｈ＋ＰＰ酶的最适ｐＨ 值在两者之间以及盐胁迫前后均无改变,分别为７ ．０ 和８ ．０ 。无盐胁迫下野生型液胞膜５８ ｋＤ 蛋白带缺失,盐胁迫下这一蛋白有微弱的表达。与此不同,突变体５８ ｋＤ 蛋白在盐胁迫前后均有明显的表达,但其２９ ｋＤ 蛋白带在无盐胁迫下明显减弱。     

Root Exudates of Tomato Plants and Their Effect on the Growth and Antifungal Activity of Pseudomonas Strains

The study of the effect of the root exometabolites of tomato plants on the growth and antifungal activity of plant growth–promoting Pseudomonas strains showed that the antifungal activity of plant growth–promoting rhizobacteria in the plant rhizosphere may depend on the sugar and organic acid composition of root exudates.     

低温、高pH胁迫对水稻幼苗根系质膜、液泡膜ATP酶活性的影响

以耐冷性不同的两个水稻品种为材料,比较研究了幼苗根系质膜、液泡膜ATP酶对低温(8℃)及高pH(8.0)胁迫的反应。结果表明水稻根细胞质膜和液泡膜上均存在Ca3+-ATP酶,但活性远低于H+-ATP酶。耐冷品种武育粳3号经低温(8℃)处理2d,根系质膜和液泡膜H+-ATP酶、Ca2+-ATP酶活性均明显升高,至冷处理12d,H+-ATP酶、Ca2+-ATP酶活性有所下降,但仍与对照相近;而冷敏感品种汕优63经低温(8℃)处理2d,根系质膜H+-ATP酶活性略有升高,而质膜Ca2+-ATP酶以及液泡膜H+-ATP酶、Ca2+-ATP酶活性已明显下降;至冷处理12d,4种酶活性均明显低于对照。高pH胁迫使质膜和液泡膜H+-ATP酶活性下降,而使Ca2+-ATP酶活性上升。高pH胁迫会加剧低温冷害。结果表明,耐冷品种质膜、液泡膜ATP酶比冷敏感品种对低温胁迫有更强的适应能力。