钙在6-BA诱导黄化绿豆幼苗下胚轴原生质体体积膨大中的作用

对照和仅用6-BA(无Ca~(2 ))处理的原生质体的体积均无变化。含钙培养液中的原生质体经6-BA处理后10min~(45)Ca~(2 )积累明显增多,15min后开始膨大;处理30min时~(45)Ca~(2 )积累最多,此时原生质体的膨大效应最好;随后~(45)Ca~(2 )积累和膨大效应逐渐下降。两者的时间进程十分相似。K~ 、Zn~(2 )、Ba~(2 )、Mg~(2 )等可在不同程度上代替Ca~(2 )的作用。EGTA、verapamil和LaCl_3处理均可使原生质体~(45)Ca~(2 )累积降到对照的水平,膨大效应完全消失。表明Ca~(2 )可能在6-BA诱导原生质体膨大的过程中起着重要作用。     

钙调素在IAA和6-BA诱导绿豆下胚轴原生质体膨大过程中的含量变化

含钙培养液和含激素培养液中的绿豆下胚轴原生质体在培养30min时分别检测到钙调素（CaM）峰,在含钙培养液中加入IAA或6-8ACaM含量急剧降低,这与先前的试验结果即45Ca2 积累增多和体积膨大正好对应。异博定（verapamil）、LaCl3、EGTA或W7可使激素 CaCl2处理的CaM含量不同程度地回升,甚至接近或超过对照的水平。而A23187处理或K 、Zn2 等代替Ca2 则使CaM含量保持在与激素处理相似的低水平。这也与先前观察到的45Ca2 积累和体积的变化相对应。表明钙调素在IAA和6-8A诱导绿豆下胚轴原生质体膨大过程中的境与Ca2 共同起着调节作用。     

KT和Ca2+对绿豆下胚轴原生质体的体积和CaM含量的影响

以黄化绿豆幼苗下胚轴原生质体为材料,探讨钙信使系统在KT诱导原生质体体积变化中的作用。lμmol/L KT可诱导含钙培养液中绿豆下胚轴原生质体膨大,处理后30min达到最大体积。Ca2 通道阻断剂Verapamil、Ca2 通道竞争性抑制剂LaCl3和钙调素拮抗剂TFP、CPZ可明显抑制KT诱导的原生质体膨大。另一方面,无论是KT处理还是对照(CaCl2单独处理),原生质体内CaM含量均在处理后30min时达到峰值,前者是后者的5倍．在KT CaCl2处理液中加入5μmol/L．Verapamil、50μmol/L LaCl3、5μmol/L,TFP或CPZ后原生质体内CaM含量都大大降低。以上结果表明,CaM可能与Ca2 共同参与KT的信号传递。     

光敏色素对黄化绿豆幼苗下胚轴原生质体钙吸收的调节

红光引起黄化绿豆(Phaseolus raditus L.)幼苗下胚轴原生质体积累~(45)Ca~(2 ),在光辐照度未达到饱和值前,~(45)Ca~(2 )积累量与光照强度或光照时间呈正相关;远红光可逆转红光引起的~(45)Ca~(2 )积累,~(45)Ca~(2 )积累的多寡取决于最后一次是照射红光还是远红光,表明光敏色素对Ca~(2 )吸收具有调节作用。     

钙调素在IAA和6—BA诱导绿豆下胚轴原生质体膨大过程中的 …

含钙培养液和含激素培养液中的绿豆下胚轴原生质体在培养３０ｍｉｎ时分别检测到钙调素峰,在含钙培养液中加入ＩＡＡ和６－ＢＡ,ＣａＭ含量急剧降低,这与先前的试验结果即＾４５Ｃａ＾２＋积累增多和体积膨大正好对应。异搏定,ＬａＣｌ３,ＥＧＴＡ或Ｗ７可使激素＋ＣａＣｌ２处理的ＣａＭ含量不同程度地回升,甚至接近或超过对照的水平。     

光敏色素对黄化绿豆幼苗下胚轴原生质体膨大的调节作用

红光引起黄化绿豆（ＰｈａｓｅｏｌｕｓｒａｄｉｔｕｓＬ．）幼苗下胚轴原生质体膨大,远红光可逆转红光的作用。这种可逆现象至少能在两个红光－远红光循环中观察到;膨大反应与红光光照强度和时间呈正相关,表明黄化绿豆幼苗下胚轴原生质体膨大是由光敏色素诱导的。红光引起的膨大只是在培养液中有Ｃａ２＋ 存在时才能发生,Ｍｇ２＋ 、Ｂａ２＋ 、Ｚｎ２＋ 或Ｋ＋ 均不能替代Ｃａ２＋ 的作用。膨大与原生质体吸水有一定关系     

在ts-RSV LA90细胞转化过程中钙流变化的研究

本文以ts-RSV LA90细胞为模型,用放射性同位素示踪技术测定了通过细胞质膜的~(45)Ca~(2+)流水平;同时用钙指示剂Indo-1 AM和光学多道分析仪测定了胞内[Ca~(2+)]_i,初步研究了Ca~(2+)流和[Ca~(2+)]_i在v-src基因引起细胞转化过程中的动态变化。结果表明LA90细胞质膜上~(45)Ca~(2+)流的改变是细胞转化过程中可以检测到的早期事件之一,转化状态(33℃)细胞的~(45)Ca~(2+)流大于正常状态(40℃)的,细胞从正常到转化(40℃→33℃)的25分钟内~(45)Ca~(2+)流就有明显增大。TMB-8可以抑制转化引起的~(45)Ca~(2+)流出的增大,小牛血清可以刺激正常状态细胞的~(45)Ca~(2+)流出增大,~(45)Ca~(2+)流出与温度有一定依赖关系;细胞转化引起的~(45)Ca~(2+)流入增大,可被异博定抑制,~(45)Ca~(2+)流入不受温度的影响。LA90细胞[Ca~(2+)]_i在转化早期有明显升高,并维持在较正常细胞高2—3倍的水平,A23187-Br可提高正常LA90细胞[Ca~(2+)]_i,[Ca~(2+)]_i不受温度的影响。从质膜上~(45)Ca~(2+)流和[Ca~(2+)]_i的增大说明转化细胞虽然对胞外Ca~(2+)浓度依赖性下降,但维持增殖及转化状态仍然需要一定的胞外Ca~(2+),并通过提高质膜Ca~(2+)流入和释放内源性Ca~(2+),使转化细胞[Ca~(2+)]_i维持在较高水平上。LA90细膜质膜上~(45)Ca~(2+)流和[Ca~(2+)]_i的增大在细胞转化中起着重大作用。     

介质钙离子对白芷悬浮培养细胞及其原生质体增殖的影响

本工作首先利用《复杂络合平衡体系》计算并配制了对自由钙离子浓度具有络合平衡缓冲能力的MS液体培养基,并用电极法验证了其可靠性。在精确控制Ca~(2 )浓度条件下,利用计数法和~3H-TdR标记DNA合成的方法系统研究了不同钙离子浓度对白芷悬浮细胞及原生质体细胞增殖的影响。原生质体第一次细胞分裂所需Ca~(2 )浓度(10mmol/L)比细胞增殖所需Ca~(2 )浓度(1mmol/L)为高;不同钙离子浓度对原生质体壁再生、活力及第一次细胞分裂的作用也不一样,壁再生所需最适Ca~(2 )浓度为50mmol/L,原生质体存活以及第一次细胞分裂所需最适Ca~(2 )浓度为5—10 mmol/L,当Ca~(2 )浓度小于10~(-4)mol/L时细胞及原生质体的增殖受到很大程度的抑制,细胞死亡数目较多。结果表明介质钙离子浓度与细胞及原生质的增殖密切相关。     

激发子诱发小麦叶肉细胞原生质体微管骨架排列格局与[Ca2+]cyt的变化

以小麦叶肉细胞原生质体-激发子互作为研究体系,通过免疫荧光标记和Ca~(2 )荧光染料的装载并结合药理学试验,借助激光共聚焦扫描显微镜观察,探讨小麦抵抗叶锈菌侵染过程中微管骨架和Ca~(2 )之间的内在联系。试验结果表明,激发子处理可引起抗性品种原生质体[Ca~(2 )]_(cyt)的升高并诱发微管骨架的解聚,预解聚微管骨架,再用激发子处理,可使抗性品种原生质体[Ca~(2 )]_(cyt)的升高幅度增加。     

几种二价阳离子及表面活性剂对元麦叶原生质体电泳率的影响(简报)

原生质体电泳率的研究已应用于了解质膜表面的电荷特性。Ca~( )能影响原生质体质膜表面的电荷状况,在诱导融合时起重要作用。关于二价阳离子对质膜功能的影响,Caldwell报道了Ca~( )、Mg~( )、Mn~( )等多种二价阳离子对质膜ATP酶不同的激活效应。此外,Helenius等指出表面活性剂能改变膜的结构,并与膜脂作用而引起溶胞。为进一步了解不同的二价阳离子对质膜电荷特性的影响,及表面活性剂在改变膜结构这一复杂过程中对质膜电性影响的状况,我们报道Ca~( )、Mg~( )、Mn~( )等二价阳离子及几种表面活性剂对原生质体电泳率影响的结果。     

钙在IAA诱导绿豆下胚轴原生质体膨大过程中的作用

This paper studied on the role of calcium in IAA-induced swelling of protoplasts isolated from hypocotyl in etiolated mung bean (Phaseolus radiatus L.) seedlings. Protoplasts incubated in CaCl2-bearing medium without hormone maintained a constant volume and a consistent intensity of 45Ca2+ radioactivity. To treat with IAA, they began to swell and continually swelled to the maximum volume 30 minutes later (Fig. 2). However, the protoplasts could not swell when IAA was added into the medium without CaCl2 (Fig. 1). It was suggested that Ca2+ may be necessary for IAA to induce protoplast swelling. And also, IAA enabled the protoplasts to swell in less extent with K+, Zn2+, Ba2+ or Mg2+ instead of Ca2+ (Fig. 3). Radioisotope experiments showed that K+ influx increased when K+ replaced Ca2+ (Fig. 4), and water absorption plays a role in the swelling (Fig. 5). 45Ca2+ accumulation in protoplasts treated by IAA was much higher than that of control, and the time course of 45Ca2+ accumulation was similar to that of protoplasts swelling (Fig. 6). 45Ca2+ level and the swelling of protoplasts sharply declined when EGTA, verapamil or LaCl3 was added into the medium (Table 1, 2 and 3). These results indicated that Ca2+ may play an important role in IAA-induced swelling.     

Osmoregulation by Oat Coleoptile Protoplasts (Effect of Auxin)

The effect of auxin on the physiology of protoplasts from growing oat (Avena sativa L.) coleoptiles was investigated. Protoplasts, isolated iso-osmotically from peeled oat coleoptile segments, were found to swell steadily over many hours. Incubated in 1 mM CaCl2, 10 mM KCl, 10 mM 2-(morpholino)ethanesulfonic acid/1,3-bis-[tris(hydroxymethyl)methylamino]propane, pH 6.5, and mannitol to 300 milliosmolal, protoplasts swelled 28.9% [plus or minus] 2.0 (standard error) after 6 h. Addition of 10 [mu]M indoleacetic acid (IAA) increased swelling to 41.1% [plus or minus] 2.1 (standard error) after 6 h. Swelling (in the absence of IAA) was partially dependent on K+ in the bath medium, whereas auxin-induced swelling was entirely dependent on K+. Replacement of mannitol in the bath by Glc increased swelling (in the absence of IAA) and eliminated auxin-induced swelling. Swelling with or without IAA was inhibited by osmotic shock and was completely reversed by 0.1 mM NaN3. Sodium orthovanadate, applied at 0.5 mM, only gradually inhibited swelling under various conditions but was most effective with protoplasts prepared from tissue preincubated in vanadate. Our data are interpreted to suggest that IAA increases the conductance of the plasma membrane to K+.     

Regulation of Phytochrome on Swelling of Protoplasts Isolated from Hypocotyl of Etiolated Mung Bean Seedlings

Protoplasts from hypocotyls of etiolated mung bean (Phaseolus raditus L. ) seedlings were maintained at a constant osmotic potential at 20±2℃, and they were found to swell gradually after being pulsed with red light (R) (10.5 W · m-2, 3 min) when CaCl2 was present in the medium. The volume reached maximum during 30--60 min after R-irradiation and decreased swelling afterwards. Farred light (FR) irradiation in presence or absence of Ca2+ did not influence the protoplast volume. The R-effect was photoreversible by subse- quent FR (2.5 W · m-2, 5 min) irradiation, usually seen over two R-FR cycles. Furthermore, swelling response was in positivecorrelation with red light intensity and duration of R pulse, indicating the involvement of phytoehrome. FR became less effective in reversing the effect of R after 10 min in dark between R and FR. Protoplast swelling occurred only when Ca2+ ions (1 mmol/L) then Ca2+ ions (1 mmol/L) is added to the medium 5 rain after R. The effect of Ca2+ could not be replaced by Mg2+, Ba2+, Zn2+, or K+. The time course of water (3H20) uptake into protoplasts after R-irradiation was consistent with the trend of protoplast swelling, indicating the existence of certain relationship between the swelling and water uptake of the protoplasts.     

Auxin- and abscisic acid-dependent osmoregulation in protoplasts of Phaseolus vulgaris pulvini.

Protoplasts isolated from the laminar pulvinus of Phaseolus vulgaris and bathed in a medium containing KCl as the major salt were found to swell in response to IAA and to shrink in response to ABA. The protoplasts of flexor cells and those of extensor cells responded similarly. The results indicate that the cellular content of osmotic solutes is enhanced by IAA and reduced by ABA. The IAA-induced swelling was abolished when either the K(+) or the Cl(-) of the bathing medium was replaced by an impermeant ion or when the medium was adjusted to neutral pH (instead of pH 6). The response was inhibited by vanadate. It is concluded that the swelling is caused by enhanced influxes of K(+) and Cl(-), which probably occur through K(+) channels and Cl(-)/H(+) symporters, respectively. The ABA-induced shrinking was inhibited by 5-nitro-2-(3-phenylpropylamino)-benzoic acid, an anion-channel inhibitor, suggesting that it is caused by Cl(-) efflux through anion channels and charge-balancing K(+) efflux through outward-rectifying K(+) channels. It appears that the two plant hormones act on pulvinar motor cells to regulate their turgor pressure, as they do in stomatal guard cells. The findings are discussed in relation to the pulvinar movements induced by environmental stimuli.     

Elicitor-Induced Changes in Ca2+ Influx,K+ Efflux,and 4-Hydroxybenzoic Acid Synthesis in Protoplasts of Daucus carota L

Suspension-cultured carrot cells (Daucus carota) and their protoplasts respond to a fungal elicitor prepared from the culture medium of Pythium aphanidermatum by accumulating 4-hydroxybenzoic acid (4-HBA). Protoplasts release the compound into the culture medium. Using 45CaCl2 as a tracer, we were able to demonstrate that the secretion of 4-HBA is preceded by a rapid increase in the Ca2+ influx and a concomitant K+ efflux. If the increased Ca2+ influx was prevented by ethyleneglycol-bis([beta]-aminoethylether)-N,N[prime]-tetraacetic acid, 4-HBA synthesis was inhibited by 70%. These results are discussed with regard to signal transduction from the plasma membrane to the nucleus of carrot protoplasts.     

植物单盐毒害和离子拮抗机理研究Ⅰ.单盐和混合盐对植物原生质体膜某些特性、超氧物歧化酶和过氧化氢酶活性的影响

单盐(KCl, CaCl_2或MgCl_2)和混合盐(KC_1+CaCl_2或KCl+MgCl_2)对植物原生质体完整率、存活率和膜透性等均有明显影响。K~+、Ca~(2+)或Mg~(2+)等单种阳离子明显降低原生质体膜完整率和存活率而增加其物质渗漏量,其中以单价阳离子K~+的影响为甚。上述单种阳离子还明显降低小麦幼叶超氧物歧化酶(SOD)和过氧化氢酶活性。只有由单价和二价阳离子组成的平衡混合盐才能使原生质体维持较高的完整率、存活率和较正常的膜透性.并能使细胞维持较高的SOD和过氧化氢酶活性。 认为单盐毒害机理可能是首先引起细胞膜发生不正常的膜相变或细胞累积较多的有害氧自由基,引起膜脂发生过氧化或脱酯化而破坏膜结构。在离子平衡混合盐作用下,膜系才能维持正常液晶相,具有较高活性的SOD和过氧化氢酶等生物保护性酶系是离子拮抗作用之原因。     

棉花胚珠纤维发育的研究

将未受精的棉花胚珠漂浮培养在加有不同植物激素的BT培养基上,培养48小时或96小时后,用扫描电镜观察纤维发育情况,以及测定胚珠内IAA氧化酶活性变化及内源ABA的含量变化,并和同一时期的大田生长的胚珠进行比较。结果表明:IAA+GA_3是最佳激素组合。在这种激素组合的培养基中培养的未受精胚珠,在纤维发育、酶活性变化等方面,均与大田生长的胚珠相似。这一激素组合还能抑制离体胚珠内源ABA的增长,但同一时期的大田生长的胚珠,其内源ABA含量却相对要高。     

Two distinct signaling pathways participate in auxin-induced swelling of pea epidermal protoplasts

Protoplast swelling was used to investigate auxin signaling in the growth-limiting stem epidermis. The protoplasts of epidermal cells were isolated from elongating internodes of pea (Pisum sativum). These protoplasts swelled in response to auxin, providing the clearest evidence that the epidermis can directly perceive auxin. The swelling response to the natural auxin IAA showed a biphasic dose response curve but that to the synthetic auxin 1-naphthalene acetic acid (NAA) showed a simple bell-shaped dose response curve. The responses to IAA and NAA were further analyzed using antibodies raised against ABP1 (auxin-binding protein 1), and their dependency on extracellular ions was investigated. Two signaling pathways were resolved for IAA, an ABP1-dependent pathway and an ABP1-independent pathway that is much more sensitive to IAA than the former. The response by the ABP1 pathway was eliminated by anti-ABP1 antibodies, had a higher sensitivity to NAA, and did not depend on extracellular Ca(2+). In contrast, the response by the non-ABP1 pathway was not affected by anti-ABP1 antibodies, had no sensitivity to NAA, and depended on extracellular Ca(2+). The swelling by either pathway required extracellular K(+) and Cl(-). The auxin-induced growth of pea internode segments showed similar response patterns, including the occurrence of two peaks in the dose response curve for IAA and the difference in Ca(2+) requirements. It is suggested that two signaling pathways participate in auxin-induced internode growth and that the non-ABP1 pathway is more likely to be involved in the control of growth by constitutive concentrations of endogenous auxin.