溴氰菊酯对神经细胞钙通道和 钙库的激活作用

应用膜片钳全细胞记录方式和显微荧光测钙技术,以MN9D神经细胞为材料研究了溴氰菊酯的作用机理。低浓度(10^-9 mol/L～10^-7 mol/L)溴氰菊酯就能使神经细胞Ca²⁺电流显著增加。10^-9 mol/L,1 min时电流增加平均值为20.64%,5 min时为15.48%,表明溴氰菊酯能激活高电位激活钙通道(L型和N型),促使Ca²⁺内流,显微荧光测定细胞内自由钙离子浓度（［Ca²⁺］_I）发现,在含Ca²⁺和无Ca²⁺的胞外液中,溴氰菊酯均能使胞内自由钙离子数量增加,表明它能刺激胞内钙库释放Ca²⁺。［Ca²⁺］_I升高对细胞功能影响很大。     

Ca2+对韭兰花粉萌发和花粉管生长的影响

采用离体花粉培养技术,研究不同浓度Ca²⁺对韭兰花粉萌发和花粉管生长的影响。结果表明,较低浓度(10^-3 mol/L)的Ca²⁺对花粉萌发具明显地促进作用,并促进花粉管较快伸长;而过高或过低浓度则起不到促进的作用。     

香蕉不同成熟度果实活性氧、乙烯与淀粉酶活性相关性研究

采用各种活性氧诱发剂(0.5g/L百草枯、10mmol/L H₂O₂和10mmol/L H₂O₂+10mmol/L FeSO₄·7H₂O)及相应的清除剂(20mmol/L没食子酸丙酯、10个单位CAT和70mmol/L DMSO)、外源乙烯(750μl/L乙烯利)、乙烯生成先导物(合成前体,1mmol/L ACC)和乙烯合成抑制剂(10mmol/L AOA)处理香蕉果肉切片。结果表明,在不同成熟度的香蕉果实中,只有O₂^·存在及乙烯合成不受抑制时,淀粉酶活性才能呈现,果实才能软化、成熟;而O₂^·及OH^·可能在乙烯合成中所起的作用有所不同。     

干旱条件下钙离子对一氧化氮诱导黄瓜不定根发生的影响

以黄瓜品种‘新春4号’为材料,研究干旱胁迫下一氧化氮(NO)和钙离子(Ca²⁺)处理下黄瓜的生根指标、内源Ca²⁺荧光强度以及抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT、抗坏血酸过氧化物酶APX)活性,分析干旱条件下黄瓜不定根发生过程中NO和Ca²⁺之间的关系.结果表明: 200 μmol·L^-1 氯化钙(CaCl₂)和0.05%聚乙二醇(PEG)共处理显著提高了干旱条件下黄瓜不定根的根长和根数;添加Ca²⁺螯合剂(EGTA)和通道抑制剂(BAPTA/AM)处理显著降低了干旱条件下NO诱导的不定根根数和根长.干旱条件下,NO和CaCl₂处理提高了黄瓜下胚轴内源Ca²⁺荧光强度;而NO清除剂(cPTIO)处理的Ca²⁺荧光强度显著低于NO处理.干旱条件下,NO和CaCl₂处理显著提高了黄瓜下胚轴抗氧化酶活性;而Ca²⁺抑制剂或螯合剂处理显著降低了NO诱导的抗氧化酶活性.由此可见,干旱条件下Ca²⁺参与了NO调控黄瓜抗氧化酶活性,缓解了干旱胁迫对不定根形成产生的伤害,进而促进了不定根的发生.     

马尾松MAPK级联途径应答信号物质基因的表达分析

MAPK(mitogen-actived protein kinase)在响应和调控生物与非生物胁迫、激素调节等方面发挥重要作用。马尾松MAPK级联途径7个基因被鉴定,并进行分子特性和外源信号物质处理表达模式分析。结果表明,马尾松与火炬松、北美云杉等针叶裸子植物的关系较近,不同类型基因具有该类基因特有的MAPK结构域以及典型催化氨基酸基序,D(I/L/V)K是马尾松MAPK基因共有的活性基序,PmMAP4K与MAPK级联途径的3个成员未直接互作,MAPK级联途径基因可能通过磷酸化调控各种激素生物合成来响应非生物胁迫。7个基因均响应了MeJA、GA、SA、ABA、Ca²⁺处理,但模式不同。PmMAP4K基因对Ca²⁺处理响应明显,其次是PmMAP2K基因,其它基因对单独Ca²⁺处理响应不明显,4种激素和Ca²⁺共同处理均提高了基因表达量,MeJA+Ca²⁺处理MAPK基因表达量高于单独MeJA处理,而GA、SA、ABA单独处理基因的表达量高于其与Ca²⁺一起...     

膨大期果面喷施IAA对桃成熟期果实性状和相关基因表达的影响北大核心CSCD

为明确桃果实发育后期外源生长素对果实成熟的影响及更深入的认识生长素调控果实发育与成熟的机制,本研究以桃品种‘小白凤’为试材,采用不同浓度的外源IAA(200,10,0.1μmol/L)喷施第2次快速膨大期的桃果实,在处理后10,20,30 d分别取样,分析桃果实的硬度,糖组分(蔗糖、葡萄糖、果糖、山梨醇),果胶,纤维素含量以及乙烯释放量的变化,并对200μmol/LIAA处理后30 d及对照组的果实进行了转录组测序分析,深入认识生长素调控桃果实成熟的作用和机理。结果表明,(1)IAA处理后30 d时,200μmol/L处理组桃果实果肉硬度与对照组相比显著增加,成熟期平均延迟5 d,而10,0.1μmol/LIAA处理组与同期对照组间无显著差异。(2)果肉蔗糖含量在0.1,200μmol/LIAA处理后30 d显著低于同期对照组,在10μmol/LIAA处理后30 d时与对照组无显著差异;葡萄糖、果糖和山梨醇含量在各浓度IAA处理后30 d时多与对照组间无明显差异。(3)在处理30 d时,果肉中可溶性果胶含量在0.1μmol/L IAA处理组与对照组无显著差异,在10,200μmol/LIAA处理组均显著低于对照组,此时不同浓度IAA处理桃果肉中不可溶果胶和纤维素含量均与对照组之间无显著差异。(4)在IAA处理后10,20,30 d时,果实乙烯释放量均表现为0.1,10μmol/L处理与对照组无显著差异,200μmol/L处理组显著低于对照组。(5)转录组数据显示,200μmol/L IAA处理与对照组中共存在86个差异表达基因,KEGG分析发现其中有6个与果实发育成熟密切相关的代谢途径中多个基因的表达谱发生显著变化,且变化趋势与已测定的生理指标数据吻合。综合分析表明200μmol/L的外源IAA处理第2次快速膨大期的桃果实能够延缓果实成熟的进程。     

薯蓣皂苷对大鼠心肌收缩与钠-钙交换体的影响

目的：观察薯蓣皂苷（Dio）对大鼠心肌收缩作用以及胞内Ca²⁺浓度的影响,并初步探讨其作用机制与Na⁺-Ca²⁺交换体（NCX）的关系。方法：采用Langendorff逆行主动脉灌流法对大鼠离体心脏进行灌流,利用压力感受器插管法测定左心室相关心功能参数,记录及其在应用NCX选择性抑制剂SEA0400情况下对左心室收缩压（LVSP）、左心室舒张末期压（LVEDP）、左心室内压最大上升/下降速率（±dp/dt_max）以及心率（HR）的影响;利用激光共聚焦显微观察薯蓣皂苷及SEA0400对大鼠心肌细胞H9c2细胞内Ca²⁺浓度的影响。结果：离体心脏灌流结果显示,1 μmol/L Dio可显著增加LVSP,增加约19.7%（P<0.01）;增加左室内压最大上升速率（+dp/dt_max）,增加约9.6%;激光共聚焦测定Ca²⁺荧光强度实验结果显示：1 μmol/L Dio可使H9c2细胞中Ca²⁺相对荧光强度增加（P<0.01）;而在SEA0400存在的情况下,1 μmol/L的Dio使细胞内Ca²⁺相对荧光强度变为（17.09±0.63）,给予Dio后差异有显著性（P<0.01）。在细胞液中无Ca²⁺或无Na⁺时,给予1 μmol/L的Dio使Ca²⁺相对荧光强度减小,与给予1 μmol/L的Dio差异有显著性（P<0.01）。结论：Dio可增加左心室收缩压和最大上升速率,表现正性肌力作用;Dio可使细胞内Ca²⁺浓度增加,其作用机制与增加Na⁺内流,促进NCX反向转运有关。     

A23187和EGTA对光周期诱导菊花成花及其过程中叶片Ca2+分布和碳水化合物的影响

以切花菊品种‘神马’为试材,研究光周期诱导菊花成花过程中Ca²⁺载体A23187和Ca²⁺螯合剂EGTA处理对花芽分化及其过程中叶片Ca²⁺分布和蔗糖、可溶性糖及淀粉含量变化的影响.结果表明：对照叶片Ca²⁺含量在花芽未分化期（Ⅰ）处于较低水平,而在花芽分化启动期（Ⅱ）迅速增加并达到高峰,之后下降;Ca²⁺亚细胞定位表明,在未分化期（Ⅰ）Ca²⁺沉淀主要分布在液泡、细胞壁和细胞间隙中,细胞质内较少,而在花芽分化启动期（Ⅱ）细胞质内积累大量的Ca²⁺沉淀.A23187处理的菊花花芽分化开始和结束时间比对照分别提前2 d和3 d,叶片Ca²⁺含量比对照显著增加;EGTA处理的叶片Ca²⁺含量比对照显著减少,花芽分化开始和结束时间分别比对照推迟4 d和8 d;A23187和EGTA处理的叶片Ca²⁺在花芽分化启动期（Ⅱ）均向细胞质流入并密集.A23187处理的蔗糖和可溶性糖含量在处理2 d时达到峰值,比对照达到峰值的时间提前2 d,与Ca²⁺达到峰值的时间一致,而EGTA处理的蔗糖和可溶性糖含量在处理2 d时没有明显变化,8 d时才迅速增加达到峰值,即所有处理的蔗糖、可溶性总糖含量在花芽分化启动期（Ⅱ）均增加并达到高峰,之后有所减少,但其在整个花芽分化过程均高于光周期诱导前的含量;对照和A23187处理的淀粉含量在处理2 d时开始减少,而EGTA则在处理8 d后开始减少,至花芽分化结束所有处理的淀粉含量均保持较低水平（低于诱导前）.表明Ca²⁺碳水化合物参与了光周期诱导的菊花成花过程.     

盐胁迫下外源褪黑素和Ca2+对甜瓜幼苗的缓解效应

以甜瓜品种‘羊角酥瓜’为试材,利用人工气候室控制环境条件(昼/夜25/18 ℃),研究盐胁迫条件下外源褪黑素(MT)和Ca²⁺对甜瓜幼苗根系和叶片中Cl^-、Na⁺、K⁺、Mg²⁺、Ca²⁺离子含量,Na⁺/K⁺、 Na⁺/Ca²⁺、Na⁺/Mg²⁺值,以及H⁺-ATP酶活性、渗透调节物质积累和细胞膜质过氧化的影响.结果表明: 与对照相比,盐胁迫处理显著抑制甜瓜幼苗生长,增加根系和叶片中Cl^-、Na⁺含量,降低K⁺、Mg²⁺、Ca²⁺含量.盐胁迫下,喷施外源MT或Ca²⁺处理均可以显著降低甜瓜根系和叶片中Cl^-、Na⁺含量,提高K⁺、Mg²⁺、Ca²⁺含量,植株体内Na⁺/K⁺、Na⁺/Ca²⁺和 Na⁺/Mg²⁺值下降;同时也提高了根系和叶片H⁺-ATP酶活性及叶片渗透调节物质的含量,降低盐胁迫对细胞膜的伤害,表现在甜瓜叶片相对电导率和丙二醛含量降低.总之,在盐胁迫条件下,外源MT、Ca²⁺单独和复配处理均可通过提高H⁺-ATP酶活性来降低盐害离子的含量,改善甜瓜幼苗中的离子平衡,同时增加渗透调节物质的含量,降低膜质过氧化水平,从而增强其对盐胁迫的适应性,其中MT和Ca²⁺复配处理时的效果更好.复配外施 MT 和Ca²⁺在诱导甜瓜幼苗提高耐盐方面具有协同增效作用.     

盐胁迫下外源褪黑素和Ca2+对甜瓜幼苗的缓解效应

以甜瓜品种‘羊角酥瓜’为试材,利用人工气候室控制环境条件(昼/夜25/18 ℃),研究盐胁迫条件下外源褪黑素(MT)和Ca²⁺对甜瓜幼苗根系和叶片中Cl^-、Na⁺、K⁺、Mg²⁺、Ca²⁺离子含量,Na⁺/K⁺、 Na⁺/Ca²⁺、Na⁺/Mg²⁺值,以及H⁺-ATP酶活性、渗透调节物质积累和细胞膜质过氧化的影响.结果表明: 与对照相比,盐胁迫处理显著抑制甜瓜幼苗生长,增加根系和叶片中Cl^-、Na⁺含量,降低K⁺、Mg²⁺、Ca²⁺含量.盐胁迫下,喷施外源MT或Ca²⁺处理均可以显著降低甜瓜根系和叶片中Cl^-、Na⁺含量,提高K⁺、Mg²⁺、Ca²⁺含量,植株体内Na⁺/K⁺、Na⁺/Ca²⁺和 Na⁺/Mg²⁺值下降;同时也提高了根系和叶片H⁺-ATP酶活性及叶片渗透调节物质的含量,降低盐胁迫对细胞膜的伤害,表现在甜瓜叶片相对电导率和丙二醛含量降低.总之,在盐胁迫条件下,外源MT、Ca²⁺单独和复配处理均可通过提高H⁺-ATP酶活性来降低盐害离子的含量,改善甜瓜幼苗中的离子平衡,同时增加渗透调节物质的含量,降低膜质过氧化水平,从而增强其对盐胁迫的适应性,其中MT和Ca²⁺复配处理时的效果更好.复配外施 MT 和Ca²⁺在诱导甜瓜幼苗提高耐盐方面具有协同增效作用.     

钙对香蕉采后乙烯释放的抑制

本实验用CaCl_2溶液对香蕉(Musa acuminata cf. 'Dwarf Davendish')组织进行真空浸透处理,研究Ca~(2 )对香蕉采后乙烯释放、EFE活性、ACC水平以及ACC/MACC比值的影响。结果表明,Ca~(2 )处理可抑制香蕉果皮和果肉组织乙烯生成,对抑制果皮的乙烯生成尤为明显。Ca~(2 )处理还可降低内源ACC水平,抑制EFE活性。结果还显示,Ca~(2 )处理对组织中ACC/MACC比值有一定影响。     

Uptake and polar transport of indoleacetic acid in moss rhizoids

In the cucumber ( Cucumis sativus L. cv. Straight Eight) cotyledon expansion assay, cytokinin-stimulated ethylene production was separated from cytokinin-stimulated growth through the use of potassium and calcium salts. Low concentrations of KC1, which dramatically promoted growth induced by cytokinin, inhibited ethylene evolution, while CaCl₂ at a concentration that had no effect on growth, strongly promoted the cytokinin-induced ethylene evolution. In contrast to the growth response, stimulation of ethylene production was not directly related to the presence of potassium or calcium but to their relative concentrations. Concentrations of KCl and CaCl₂ which promoted ethylene evolution singly, strongly inhibited it when mixed together. Low rates of exogenous ethylene had no effect on the growth response. Both the growth and ethylene responses were found to be general cytokinin phenomena. Cotyledon respiration was promoted by KC1, CaCl₂ and cytokinin, but its stimulation was not correlated with either growth or ethylene production. In the presence of KClm cytokinin-induced respiration sharply lowered the content of certain sugars during the large growth response and followed KCl uptake. Analysis of KCl uptake showed that its growth promoting synergism with cytokinin was not due to osmotic effects.     

成熟和褐变荔枝果实呼吸作用和脂氧合酶活性

荔枝果实完全成熟和果皮变鮮红时,呼吸速率降低,仅相当于果皮带绿时的39.4％。此时果皮和果肉的脂氧合酶活性亦明显降低,分别相当于后者的60.2％和49.1％。成熟荔枝果实果皮呼吸作用对KCN抑制敏感。2mM KCN抑制果皮总呼吸的91.8％,而仅抑制果肉的56.9％。荔枝果皮呼吸的电了传递主要是通过细胞色素氧化酶途径,而果肉則可能一半是通过其它氧化酶途径。2mKCN和1.5mM SHAM抑制成熟果皮总呼吸97.9％,为SHAM抑制的交替途径呼吸占总呼吸5.28％。相同浓度KCN和SHAM抑制褐变果皮总呼吸79.7％,则SHAM抑制的交替途径呼吸占27.1％。果实褐变时,果成交替途径呼吸比例增高。这一变化可能促进H_2O_2积累、乙烯产生和果皮褐变深化。     

钙对香蕉采后果实呼吸的影响

本实验对香蕉成熟过程中水溶性钙的变化及CaCl_2溶液真空浸渗处理对香蕉果实呼吸作用的影响进行研究,结果表明,香蕉成熟期间,水溶性钙含量随成熟度的提高而增加,果实呼吸跃变上升前期,水溶性钙的增加尤为明显,果皮和果肉中水溶性钙含量与采后成熟天数呈正相关。以0.05mol/l和0.1mol/l CaCl_2溶液真空浸渗,可使香蕉果实呼吸跃变高峰延迟,但没有明显降低跃变峰值。     

Carbon dioxide and ethylene interactions in tulip bulbs

The effect of CO₂ on ethylene-induced gummosis (secretion of polysaccharides), weight loss and respiration in tulip bulbs ( Tulipa gesneriana L.) was investigated. A pretreatment with 1-MCP prevented these ethylene-induced effects, indicating that ethylene action must have been directed via the ethylene receptor. Treatment with 0.3 Pa ethylene for 2 days caused gummosis on 50% of the total number of bulbs of cultivar Apeldoorn, known to be sensitive for gummosis. Addition of CO₂ (10 kPa) reduced the ethylene-induced gummosis to 18%. In a second experiment the influence of ethylene and CO₂ on respiration and FW loss of bulbs of the cultivar Leen van der Mark was studied. A range of ethylene partial pressures (0.003–0.3 Pa) was applied continuously for 29 days. Ethylene caused a transient peak in O₂ consumption rate during the first days after the start of application. The relation between O₂ consumption rate and ethylene partial pressure could be described by Michaelis-Menten kinetics. Respiratory peaks were reduced by CO₂. This inhibition by CO₂ could not totally be due to competition with ethylene at the receptor binding-site, as was indicated by the use of an O₂ consumption model. Pre-treatment of bulbs with 1-MCP and subsequent exposure to CO₂ showed that CO₂ could influence respiration irrespective of any interaction with ethylene. Ethylene and CO₂ both stimulated weight loss. The effect of combined treatments of ethylene and CO₂ on weight loss was at least as strong as the sum of the separate effects, which implies that competition between ethylene and CO₂ at the receptor binding-site was unlikely.     

The effect of aluminum exposure on root respiration in an aluminum-sensitive and an aluminum-tolerant cultivar of Triticum aestivum

The effects of aluminum (Al) exposure on intact root respiration of an Al-sensitive (Scout-66) and an Al-tolerant (Atlas-66) cultivar of Triticum aestivum were investigated. Exposure to a wide range of Al concentrations (0–900 μmol) for 4 days stimulated respiration along the energy-conserving cytochrome pathway in both cultivars and increased the ratio of maintenance respiration to growth respiration. The maximum rate of Scout-66 root respiration occurred after exposure to 100–200 μmol Al. Atlas-66 root respiration peaked after exposure to 300–400 μmol Al. Similarly, calculations of theoretical adenosine 5'-triphosphate (ATP) production indicated that maximum daily rate of ATP production also increased upon exposure to Al in both cultivars, with peak ATP production occurring during peak respiration. Maximum root respiration rates in both cultivars were related to the Al concentration that inhibited root growth. Temporal exposure to 200 μmol Al quickly stopped root growth and stimulated cytochrome pathway respiration in Scout-66 after 4 days. Atlas-66 root growth and respiration were unaffected by 200 μmol Al. These results suggest that Al exposure imposes a demand for additional metabolic energy. A model describing Al effects on root respiration is presented     

Changes during low-oxygen storage in the effects of ethylene on induction of ethylene synthesis and stimulation of respiration of 'Gloster 69' apples

The ability of ethylene to stimulate respiration and advance the onset of rapid ethylene production was investigated at different times during storage of 'Gloster 69' apples in 2 kPa O₂ at 1.5–3.5°C. Ethylene stimulated respiration in apples at 15°C immediately after harvest; maximal rates were recorded at 10–1000 μl I⁻¹ but attainment of these rates was delayed after low O₂ storage until day 3 of treatment at 15°C. The onset of rapid ethylene production at 15°C occurred later in non-ethylene-treated apples after storage than after harvest. Ethylene production was induced in some apples during ethylene treatment for 3 or 6 days; in others it was induced about 20 days after treatment, but a proportion of the fruit showed no induction in the 45-day duration of experiments. An ethylene treatment at 10 μl I⁻¹ led to a near maximal increase in the frequency of induction of ethylene production at all times. After storage apples were mainly induced during treatment or not induced, whereas after harvest induction after treatment was more frequent. The presence of 2000 μl l⁻¹ norbornadiene during ethylene treatment inhibited the stimulation of respiration and the induction of ethylene production; this inhibition was only partly reversed by ethylene at 1000 μl l⁻¹ the experiments suggest that receptors for ethylene were present at all stages but that response capacity changed during storage.     

Ethylene Evolution Changes in Tilted Fraxinus mandshurica Rupr. var. japonica Maxim. Seedlings in Relation to Tension Wood Formation

The effects of ethylene on tension wood formation were studied in 3-year-old Fraxinus mandshurica Rupr. var. japonica Maxim, seedlings in two separate experiments. In experiment 1, ethylene evolution of buds and stems was measured using gas chromatography after 0, 2,4, 7,14, and 21 d of treatment; in experiment 2, both aminoethoxyvinylglycine (AVG) and AgNO3 were applied to the horizontally-placed stems, and the cell numbers on sites of applications were measured after 40 d. Ethylene evolution from buds was found to be much greater in tilted seedlings than in upright ones. The cell numbers of wood fibers in shoots and 1-year-old stems were reduced in treatments with 12.5 x 10-7 μmol/L AVG, 12.5 x 10-8 μmol/L AVG, and 11.8 x 10-8 μmol/L AgNO3; whereas the horizontal and vertical diameters were reduced by treatment of 12.5 x 10-7 μnol/L AVG. Ethylene evolutions of shoots and 1-year-old stems were inhibited greatly in comparison with the control by applying 12.5 x 10-7 μmol/L AVG. The formation of a gelatinous layer of wood fibers was affected by neither AVG nor AgNO3 application. These results suggest that ethylene regulates the quantity of wood production, but does not affect G-layer formation in F. mandshurica Rupr. var. japonica Maxim, seedlings.     

Effects of anaerobiosis on ethylene production, respiration and flowering in iris bulbs

Ethylene production of iris bulbs (Iris hollandica cv. Ideal) was very low. When stored at 30°C, production was 12–20 pmol C₂H₄ (kg fresh weight)^?1 h^?1. Higher temperatures (35°C, 40°C) enhanced the ethylene production; a treatment with 40°C for ca 7 days caused a 3 times higher ethylene production than at 30°. During anaerobic storage (in 100% N₂) ethylene production was equal to that of control bulbs. When after a 7 day period of anaerobiosis the N₂ was replaced by air, a burstlike ethylene production was observed. Twenty-four h after the replacement, ethylene production was equal to control values again. The effects of this production of ethylene on mitochondrial respiration and flowering were investigated. When mitochondria were isolated immediately after the anaerobic treatment (before the enhanced ethylene production) alternative pathway capacity was not detectable, a situation also occurring in control bulbs. When mitochondria were isolated 24 h after the end of the anaerobiosis (after the ethylene burst) uninhibited respiration did not change significantly, but a capacity of the alternative pathway was observed. The increase in alternative pathway capacity after anaerobiosis was partly inhibited by 2,5-norbornadiene (NBD), an ethylene antagonist. Fermentation occurred during anaerobiosis: ethanol concentrations increased during the treatment and decreased when air was supplied. When bulbs were exposed to ethanol vapour the alternative pathway was induced but only when very high ethanol levels in the bulbs were reached. The amount of ethanol accumulated in the bulbs during a 7 day anaerobic treatment was far too low to explain the observed induction of alternative pathway capacity. Flowering percentages were enhanced after a 24 h treatment with ethylene and after a 7 day anaerobic treatment. NBD significantly inhibited the effect of exogenous ethylene and of anaerobiosis on flowering. Ethanol was not able to induce flowering. The burst-like production of ethylene after anaerobiosis probably is responsible for the effects on respiration and flowering.     

氨基甙类抗生素对家兔离体颈动脉窦压力感受器放电的抑制作用

实验用自制的压力感受器标本灌流－记录一体化装置,研究氨基甙类抗生素,胞外钙离子浓度变化和L－型钙通道拮抗剂对家兔离体颈动脉窦压力感受器活动（CS－BRA）的影响,研究中发现,（1）链霉素（0．24－0．75mmol/L)和庆大霉素（0．43－1．29mmol/L)浓度依赖性地抑制S－BRA,停药后可基本恢复;（2）高钙灌流液（3．3mmol/L)抑制S－BRA,而微量钙灌流液（10^-5mmol/L数量级）兴奋CS－BRA;（3）维拉帕米和地尔硫卓和选择怀阻断L－型钙通道的有效浓度范围内（＜106-7mol/L)对CS－BRA没有显著影响,在更高浓度（＞10^-6mol/L)时,则抑制CSBRA。结果表明。（1）氨基甙类抗生素特异性地抑制CS－BRA,是一种新的研究压力感受器活动的工具药;（2）钙离子不是形成压力感受器发生器电位的主要离子,而且L－型钙通道在CS－BRA中没有显著作用;（3）氨基甙类抗生素对CS－BRA的抑制作用可能不是阻断L－型钙通道实现的。