共查询到20条相似文献,搜索用时 31 毫秒
1.
Pertl H Himly M Gehwolf R Kriechbaumer R Strasser D Michalke W Richter K Ferreira F Obermeyer G 《Planta》2001,213(1):132-141
A 14-3-3 protein has been cloned and sequenced from a cDNA library constructed from mRNAs of mature pollen grains of Lilium longiflorum Thunb. Monoclonal antibodies (MUP 5 or MUP 15) highly specific against 14-3-3 proteins recognised a 30-kDa protein in the
cytoplasmic fraction of many various lily tissues (leaves, bulbs, stems, anther filaments, pollen grains, stigmas) and in
other plants (Arabidopsis seedlings, barley recombinant 14-3-3). In addition, 14-3-3 proteins were detected in a microsomal fraction isolated from
pollen grains and tubes, and the amount of membrane-bound 14-3-3 proteins as well as the amount of the plasma membrane (PM)
H+ ATPase increased during germination of pollen grains and tube growth. No change was observed in the cytoplasmic fraction.
A further increase in the amount of 14-3-3 proteins in the microsomal fraction was observed when pollen grains were incubated
in germination medium containing 1 μM fusicoccin (FC) whereas the number of 14-3-3s in the cytoplasmic fraction decreased.
Fusicoccin also protected membrane-bound 14-3-3 proteins from dissociation after washing with the chaotropic salt KI. Furthermore,
FC stimulated the PM H+ ATPase activity, the germination frequency and the growth rate of pollen tubes, thus indicating that a modulation of the
PM H+ ATPase activity by interaction with 14-3-3 proteins may regulate germination and tube growth of lily pollen.
Received: 20 June 2000 / Accepted: 2 October 2000 相似文献
2.
Gerhard Obermeyer Rosa Kriechbaumer Doris Strasser Angela Maschessnig Friedrich-Wilhelm Bentrup 《Physiologia plantarum》1996,98(2):281-290
The stimulation of the plasma membrane (PM) H+-ATPase by boric acid was studied on a microsomal fraction (MF) obtained from ungerminated, boron-dependent pollen grains of Lilium longiflorum Thunb. which usually need boron for germination and tube growth. ATP hydrolysis and H+ transport activity increased by 14 and 18%, respectively, after addition of 2-4 mM boric acid. The optimum of boron stimulation was at pH 6.5-8.5 for ATP hydrolysis and at pH 6.5-7.5 for H+ transport. No boron stimulation was detected when vanadate was added to the MF, whereas an increase of 10-20% in ATP hydrolysis and H+ transport was still measured in the presence of inhibitors specific for V -type ATPase (nitrate and bafilomycin) and F-type ATPase (azide), respectively. A vanadate-sensitive increase in ATP hydrolysis activity was also observed in partially permeabilized vesicles (0.001%[w/v] Triton X-100) suggesting a direct interaction between borate and the PM H+-ATPase rather than a weak acid-induced stimulation. Additionally, we measured the effect of boron on membrane voltage (Vm) of ungerminated pollen grains and observed small hyperpolarizations in 48% of all experiments. Exposing pollen grains to a more acidic pH of 4 caused a depolarization, followed in some experiments by a repolarization (21%). In the presence of 2 mM boron such hyperpolarizations, perhaps caused by an enhanced activity of the H+-ATPase, were measured in 58% of all tested pollen grains. The effects of boron on Vm may be reduced by additional stimulation of a K+ inward current of opposite direction to the H+-ATPase. All experiments indicate that boron stimulates an electrogenic transport system in the plasma membrane which is sensitive to vanadate and has a pH optimum around 7, i.e. the plasma membrane H+-ATPase. A boron-increased PM H+-ATPase activity in turn may stimulate germination and growth of pollen tubes. 相似文献
3.
Summary A heterogeneous distribution of H+-ATPase was visualized in germinated pollen ofLilium longiflorum using monoclonal antibodies raised against plasma membrane H+-ATPase. Immunolocalization studies of protoplasts and subprotoplasts derived from pollen tubes and sectioned pollen grains and pollen tubes show that H+-ATPases are abundant in the plasma membrane of pollen grains but are absent or sparsely distributed in the plasma membrane of pollen tubes. This polar distribution of H+-ATPases is probably the basis of the endogenous current pattern measured in growing lily pollen and involved in pollen tube tip growth.Abbreviations BSA
bovine serum albumine
- Hepes
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
- Mes
2-(N-morpholino)-ethane sulphonic acid
- PBS
phosphate buffered saline
- Pipes
piperazine-N,N-bis(2-ethanesulfonic acid)
- Tris
2-amino-2-hydroxymethyl-1,3-propandiol 相似文献
4.
Mitochondrial dysfunction mediated by cytoplasmic acidification results in pollen tube growth cessation in Pyrus pyrifolia
下载免费PDF全文
![点击此处可从《Physiologia plantarum》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yongbin Gao Hongsheng Zhou Jianqing Chen Xueting Jiang Shutian Tao Juyou Wu Shaoling Zhang 《Physiologia plantarum》2015,153(4):603-615
The length of pollen tubes grown in synthetic media is normally shorter than those grown in vivo. However, the mechanism(s) underlying the cessation of pollen tube growth under culture conditions remain(s) largely unknown. Here, we report a previously unknown correlation between vacuolar function and the cell's ability to sustain mitochondrial functions in pear pollen tubes. The pear pollen tubes in vitro grew slowly after 15 hours post‐cultured (HPC) and nearly ceased growth at 18 HPC. There was increased malondialdehyde content and membrane ion leakage at 15 HPC compared with 12 HPC. Furthermore, cytoplasmic acidification mainly mediated by decreased vacuolar H+‐ATPase [V‐ATPase, Enzyme Commission (EC) 3.6.1.3] activity was observed in pollen tubes after 15 HPC, and this further resulted in mitochondrial dysfunction, including mitochondrial structure disruption, mitochondrial membrane potential collapse and decreases in both oxygen consumption and ATP production. Our findings suggest that vacuoles and mitochondria intimately linked in regulating pollen tube elongation. 相似文献
5.
A cytochemical study on the role of ATPases during pollen germination in Agapanthus umbelatus L'Her.
Summary Cytochemical detection of ATPase activity in the pollen grain (PG) and pollen tube (PT) of Agapanthus umbelatus showed that the enzymes concerned presented specific patterns of membrane distribution according to their ionic dependencies and to the timecourse of germination and tube growth. In the pollen tubes Ca2+-ATPases were mainly localized in mitochondria and ER membranes, while Mg2+-ATPases were found especially in the tonoplast and in the membrane of the P-particles. K+-ATPases showed a high activity at the plasma membrane. In the pollen grain similar patterns of ATPase activity were observed. The highest activity of all three types was observed at the plasma membrane of the grain and at the intine and inner exine layers of the cell wall. The activity observed in the pollen grain cell wall decreased with germination time. In vivo germination studies in the presence of specific inhibitors of the ATPases showed patterns of inhibition that could be correlated with the corresponding ATPase putative role.The results are discussed in terms of the ultrastructural organization of the PG and PT, especially those correlated with (1) formation and maintenance of ionic gradients throughout the PT, (2) polarized growth and (3) hydrodynamics of PT elongation.Abbreviations PT
Pollen tube
- PG
pollen grain
- PTW
pollentube wall
- PGW
pollen-grain wall
- ER
endoplasmic reticulum
- NEM
N-ethylmaleimide 相似文献
6.
M. A. Breygina A. V. Smirnova N. P. Matveeva I. P. Yermakov 《Cell and Tissue Biology》2009,3(6):573-582
Using methods of quantitative fluorescent microscopy, we studied membrane potential changes during pollen germination and
in growing pollen tubes. Two voltage-sensitive dyes were used, i.e., DiBAC4(3), to determine the mean membrane potential values in pollen grains and isolated protoplasts, and Di-4-ANEPPS, to map the
membrane potential distribution on the surfaces of the pollen protoplast and pollen tube. We have shown that the activation
of the tobacco pollen grain is accompanied by the hyperpolarization of the vegetative cell plasma membrane by about 8 mV.
Lily pollen protoplasts were significantly hyperpolarized (−108 mV) with respect to the pollen grains (−23 mV) from which
they were isolated. We have found the polar distribution of the membrane potential along the protoplast surface and the longitudinal
potential gradient along the pollen tube. In the presence of plasma membrane H+-ATPase inhibitor sodium orthovanadate (1 mM) or its activator fusicoccin (1 μM), the longitudinal voltage gradient was modified,
but did not disappear. Anion channel blocker NPPB (40 μM) fully discarded the gradient in pollen tubes. The obtained results
indicate the hyperpolarization of the plasma membrane during pollen germination and uneven potential distribution on the pollen
grain and tube surfaces. An inhibitory analysis of the distribution of the potential in the tube has revealed the involvement
of the plasma membrane H+-ATPase and anion channels in the regulation of its value. 相似文献
7.
Plasma membrane ATPase and H+ transport activities in microsomal membranes from mycorrhizal tomato roots 总被引:4,自引:0,他引:4
ATPase activity, ATP-dependent H+ transport and the
amount of antigenic tomato plasma membrane H+-APTase
have been analysed in membrane vesicles isolated from Glomus
mosseae- or Glomus intraradices-colonized
roots and from non-mycorrhizal tomato roots. Microsomal protein content was
higher in mycorrhizal than in control roots. The specific activity of the
plasma membrane H+-ATPase was not affected by
mycorrhizal colonization, although this activity increased in membranes
isolated from mycorrhizal roots when expressed on a fresh weight basis.
Western blot analysis of microsomal proteins using antibodies raised
against the Arabidopsis thaliana plasma membrane
H+ - ATPase showed that mycorrhizal colonization did
not change the relative amount of tomato plasma membrane ATPase in the
microsomes. However, on a fresh weight basis, there was a greater amount of
this protein in roots of mycorrhizal plants. In addition, mycorrhizal
membranes showed a higher specific activity of the vanadate-sensitive
ATP-dependant H+ transport than membranes isolated
from control roots. These results suggest that mycorrhiza might regulate
the plasma membrane ATPase by increasing the coupling efficiency between
H+ transport and ATP hydrolysis. The observed
effects of mycorrhizal colonization on plasma membrane
H+-ATPase were independent of the AM fungal species
colonizing the root system. 相似文献
8.
The formation of distinct actin filament arrays in the subapical region of pollen tubes is crucial for pollen tube growth. However, the molecular mechanisms underlying the organization and dynamics of the actin filaments in this region remain to be determined. This study shows that Arabidopsis thaliana MICROTUBULE-DESTABILIZING PROTEIN25 (MDP25) has the actin filament–severing activity of an actin binding protein. This protein negatively regulated pollen tube growth by modulating the organization and dynamics of actin filaments in the subapical region of pollen tubes. MDP25 loss of function resulted in enhanced pollen tube elongation and inefficient fertilization. MDP25 bound directly to actin filaments and severed individual actin filaments, in a manner that was dramatically enhanced by Ca2+, in vitro. Analysis of a mutant that bears a point mutation at the Ca2+ binding sites demonstrated that the subcellular localization of MDP25 was determined by cytosolic Ca2+ level in the subapical region of pollen tubes, where MDP25 was disassociated from the plasma membrane and moved into the cytosol. Time-lapse analysis showed that the F-actin-severing frequency significantly decreased and a high density of actin filaments was observed in the subapical region of mdp25-1 pollen tubes. This study reveals a mechanism whereby calcium enhances the actin filament–severing activity of MDP25 in the subapical region of pollen tubes to modulate pollen tube growth. 相似文献
9.
Roman Lassig Timo Gutermuth Till D. Bey Kai R. Konrad Tina Romeis 《The Plant journal : for cell and molecular biology》2014,78(1):94-106
Reactive oxygen species (ROS) produced by NAD(P)H oxidases play a central role in plant stress responses and development. To better understand the function of NAD(P)H oxidases in plant development, we characterized the Arabidopsis thaliana NAD(P)H oxidases RBOHH and RBOHJ. Both proteins were specifically expressed in pollen and dynamically targeted to distinct and overlapping plasma membrane domains at the pollen tube tip. Functional loss of RBOHH and RBOHJ in homozygous double mutants resulted in reduced fertility. Analyses of pollen tube growth revealed remarkable differences in growth dynamics between Col–0 and rbohh–1 rbohj–2 pollen tubes. Growth rate oscillations of rbohh–1 rbohj–2 pollen tubes showed strong fluctuations in amplitude and frequency, ultimately leading to pollen tube collapse. Prior to disintegration, rbohh–1 rbohj–2 pollen tubes exhibit high‐frequency growth oscillations, with significantly elevated growth rates, suggesting that an increase in the rate of cell‐wall exocytosis precedes pollen tube collapse. Time‐lapse imaging of exocytic dynamics revealed that NAD(P)H oxidases slow down pollen tube growth to coordinate the rate of cell expansion with the rate of exocytosis, thereby dampening the amplitude of intrinsic growth oscillations. Using the Ca2+ reporter Yellow Cameleon 3.6, we demonstrate that high‐amplitude growth rate oscillations in rbohh–1 rbohj–2 pollen tubes are correlated with growth‐dependent Ca2+ bursts. Electrophysiological experiments involving double mutant pollen tubes and pharmacological treatments also showed that ROS influence K+ homeostasis. Our results indicate that, by limiting pollen tube growth, ROS produced by NAD(P)H oxidases modulate the amplitude and frequency of pollen tube growth rate oscillations. 相似文献
10.
Ruiping Zhang Gan Liu Na Wu Mian Gu Houqing Zeng Yiyong Zhu Guohua Xu 《Plant and Soil》2011,349(1-2):3-11
The plasma membrane (PM) H+ ATPase is involved in the plant response to nutrient deficiency. However, adaptation of this enzyme in monocotyledon plants to phosphorus (P) deficiency lacks direct evidence. In this study, we detected that P deficient roots of rice (Oryza Sativa L.) could acidify the rhizosphere. We further isolated the PM from rice roots and analyzed the activity of PM H+ ATPase. In vitro, P deficient rice roots showed about 30% higher activity of PM H+ ATPase than the P sufficient roots at assay of pH 6.0. The P deficiency resulted in a decrease of the substrate affinity value (K m ) of PM H+ ATPase. The proton pumping activity of membrane vesicles from the P deficient roots was about 70% higher than that from P sufficient roots. Western blotting analysis indicated that higher activity of PM H+ ATPase in P deficient roots was related to a slightly increase of PM H+ ATPase protein abundance in comparison with that in P sufficient roots. Taken together, our results demonstrate that the P deficiency enhanced activities of both PM H+-ATPase and H+ pump, which contributed to the rhizosphere acidification in rice roots. 相似文献
11.
Many signal-transduction processes in plant cells have been suggested to be triggered by signal-induced opening of calcium
ion (Ca2+) channels in the plasma membrane. Cyclic nucleotides have been proposed to lead to an increase in cytosolic free Ca2+ in pollen. However, direct recordings of cyclic-nucleotide-induced Ca2+ currents in pollen have not yet been obtained. Here, we report that cyclic AMP (cAMP) activated a hyperpolarization-activated
Ca2+ channel in the Pyrus pyrifolia pollen tube using the patch-clamp technique, which resulted in a significant increase in pollen tube protoplast cytosolic-Ca2+ concentration. Outside-out single channel configuration identified that cAMP directly increased the Ca2+ channel open-probability without affecting channel conductance. cAMP-induced currents were composed of both Ca2+ and K+. However, cGMP failed to mimic the cAMP effect. Higher cytosolic free-Ca2+ concentration significantly decreased the cAMP-induced currents. These results provide direct evidence for cAMP activation
of hyperpolarization-activated Ca2+ channels in the plasma membrane of pollen tubes, which, in turn, modulate cellular responses in regulation of pollen tube
growth. 相似文献
12.
Juyou Wu Cong Jin Haiyong Qu Xueting Jiang Jun Wu Guohua Xu Shaoling Zhang 《Acta Physiologiae Plantarum》2012,34(3):969-975
Calcium (Ca2+) plays crucial roles in regulation of pollen tube growth. The influx of Ca2+ into the pollen tube is mediated by ion channels, and the density and activity of Ca2+ channels in pollen plasma membranes critically determines their electrical properties. In this report, using whole-cell and single-channel patch-clamping techniques, we investigated developmental changes of hyperpolarization-activated Ca2+ channel activity in pear (Pyrus pyrifolia) pollen and its relationship with pollen viability. For both pollen and pollen tubes, hyperpolarization-activated Ca2+ channels had the same conductance and cAMP sensitivity, indicating that they were the same channels. However, the Ca2+ current density in pollen tube protoplasts was greater than that in pollen protoplasts. Compared with day-3 flowers’ pollen, hyperpolarization-activated Ca2+ current density was significantly lower in day 0 and day 3 flowers’ pollen, which was consistent with the pollen germination and pollen tube growth, indicating that pollen protoplasts’ increased Ca2+ current density may have enhanced the pollen viability. During pollen tube elongation, pollen tube plasma membrane Ca2+ current density increased with increased length pollen tubes up to 300 μm. All of these results indicated that hyperpolarization-activated Ca2+ channel activity was associated with in pear pollen development and may have a causal link between Ca2+ channel activity and pollen viability. 相似文献
13.
Potassium channels are controlling K+ transport across plasma membrane and thus playing a central role in all aspects of osmolarity as well as numerous other functions in plants, including in sexual reproduction. We have used whole-cell and single-channel patch-clamp recording techniques investigated the regulation of intracellular free Ca2+-activated outward K+ channels in Pyrus pyrifolia pollen tube protoplasts. We have also showed the channels could be inhibited by heme and activated carbon monoxide (CO). In the presence of oxygen and NADPH, hemoxygenases catalyzes heme degradation, producing biliverdin, iron and CO. Considered the oxygen concentration approaching zero in the ovary, the heme will inhibit the K+ outward flux from the intracellular of pollen tube, increasing the pollen tubes osmolarity, inducing pollen tube burst. Here we discuss the putative role of K+ channels in plant sexual reproduction.Key words: pear, pollen, K+ channels, heme, carbon monoxideIon channels in the pollen tube play critical roles in mediation pollen germination and pollen tube growth.1–3 Early studies were focus on the plasma membrane calcium channel regulation and cytosolic free calcium concentration variation in the pollen tube reason by which was one of the most important second messengers in plants.3–7 However, reports have also showed that the potassium channels in the pollen tubes were also involved in several important steps of plant sexual reproduction.8–19 Recently, more reports further demonstrated this phenomena.20–24 In the report by Lu et al. they demonstrated that two cation/proton exchangers (CHX), CHX21 and CHX23, are essential for pollen tube growth guidance in Arabidopsis.22 chx21 chx23 double mutant induces the fertility impaired, but which is unchanged in both single chx21 or chx23 mutants. They have also found that the double mutant pollen grains germination and pollen tube growth in the transmitting tract were not difference with the wild-type, however, the double mutant pollen tubes fail to turn toward ovules.22 Protein localization experiments show CHX23 is expressed in the endoplasmic reticulum of pollen tubes; functional analysis results showed that CHX23 as a K+ transporter mediates K+ uptake in a pH-dependent manner. So, these protein affect the signal transduction pathway of pollen tube growth toward to the ovule by controlling the cation balance and pH in the pollen tube.22 Amien et al. identified a signaling ligand of defensin-like (DEFL) protein, ZmES4, which expressed in maize synergid. ZmES4 activates the maize pollen tube tip plasma membrane K+ Shaker channel KZM1.20 This finding is also very interesting. Pollen tube bursting suggested to be based on the osmotic stress; the influx of K+ mediated by ZmES4-activated KZM1 will trigger rapid plasma membrane depolarization, which induced the pollen tube tip burst.20 Furthermore, the osmotic increasing induced by too much K+ in the cytosolic of pollen tube was not only resulted by inward K+ channel activation, but also resulted by outward K+ channel inhibition in the pollen tube plasma membrane. In our report, we find a intracellular Ca2+-sensitive outward K+ channel in pear pollen tube plasma membrane, which could be inhibited by heme and activated by heme oxidative production, carbon monoxide (CO), may play a functional role in the pollen tube brusting.23In the presence of oxygen and NADPH, hemoxygenases catalyzes heme degradation, producing biliverdin, iron and CO.25 Early reports showed that oxygen plays an important role in plant sexual reproduction. Pollen tubes grow through the style toward the ovary with high speed, a process that consumes tremendous amounts of energy and requires rapid oxygen uptake by pollen tubes.26 Pollen grains have roughly 20 times the level of mitochondria and respire 10 times faster than vegetative tissue.12,27–29 Furthermore, oxygen has been proposed as a possible cue for pollen-tube guidance.30 Indeed, the existence of an oxygen gradient in the unpollinated style has been shown in some species such as Hipeastrum hybridum. Oxygen pressure is high in the stigma and style but suddenly decreases at the base of the style, approaching zero in the ovary. Moreover, pollen-tube growth itself creates hypoxic regions within the style.31 Therefore, we suggest that the outward K+ channel inhibited by heme is dominant compared with which activated by CO when pollen tubes reach the ovary, based on where the hypoxic condition (Fig. 1). However, the gene encode the outward K+ channel in the pear pollen tube remains to be determined in the further study.Open in a separate windowFigure 1Reciprocal regulation of heme and carbon monoxide in putative Ca2+-activated outward K+ channel. Under normal condition, in the presence of NADPH, heme is metabolized by hemeoxygenase to generate carbon monoxide (CO), which activates outward K+ channel. However, without the oxygen, heme cannot be metabolized. The accumulated heme acts as an inhibitor of outward K+ channel, even in the presence of NADPH. The accumulated K+ in the cytosolic of pollen will induced the pollen tube depolarized, then burst. 相似文献
14.
Zhenzhen Zhou Haifan Shi Binqing Chen Ruihui Zhang Shanjin Huang Ying Fu 《The Plant cell》2015,27(4):1140-1161
Pollen tubes deliver sperms to the ovule for fertilization via tip growth. The rapid turnover of F-actin in pollen tube tips plays an important role in this process. In this study, we demonstrate that Arabidopsis
thaliana RIC1, a member of the ROP-interactive CRIB motif-containing protein family, regulates pollen tube growth via its F-actin severing activity. Knockout of RIC1 enhanced pollen tube elongation, while overexpression of RIC1 dramatically reduced tube growth. Pharmacological analysis indicated that RIC1 affected F-actin dynamics in pollen tubes. In vitro biochemical assays revealed that RIC1 directly bound and severed F-actin in the presence of Ca2+ in addition to interfering with F-actin turnover by capping F-actin at the barbed ends. In vivo, RIC1 localized primarily to the apical plasma membrane (PM) of pollen tubes. The level of RIC1 at the apical PM oscillated during pollen tube growth. The frequency of F-actin severing at the apex was notably decreased in ric1-1 pollen tubes but was increased in pollen tubes overexpressing RIC1. We propose that RIC1 regulates F-actin dynamics at the apical PM as well as the cytosol by severing F-actin and capping the barbed ends in the cytoplasm, establishing a novel mechanism that underlies the regulation of pollen tube growth. 相似文献
15.
In situ plasma membrane H+-ATPase activity was monitored during pH-regulated dimorphism of Candida albicans using permeabilized cells. ATPase activity was found to increase in both the bud and germ tube forming populations at 135 min which coincides with the time of evagination. Upon reaching the terminal phenotype the mycelial form exhibited higher H+-ATPase activity as compared to the yeast form. At the time of evagination H+-efflux exhibited an increase. K+ depletion resulted in attenuated ATPase activity and glucose induced H+-efflux. The results demonstrate that ATPase may play a regulatory role in dimorphism of C. albicans and K+ acts as a modulator.Abbreviations PM
Plasma membrane
- pHi
intracellular pH
- Pi
inorganic phosphorus
- TET
Toluene: Ethanol: Triton X-100 相似文献
16.
H-ATPase Activity from Storage Tissue of Beta vulgaris: IV. N,N'-Dicyclohexylcarbodiimide Binding and Inhibition of the Plasma Membrane H-ATPase
下载免费PDF全文
![点击此处可从《Plant physiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The molecular weight and isoelectric point of the plasma membrane H+-ATPase from red beet storage tissue were determined using N,N′-dicyclohexylcarbodiimide (DCCD) and a H+-ATPase antibody. When plasma membrane vesicles were incubated with 20 micromolar [14C]-DCCD at 0°C, a single 97,000 dalton protein was visualized on a fluorograph of a sodium dodecyl sulfate polyacrylamide gel. A close correlation between [14C]DCCD labeling of the 97,000 dalton protein and the extent of ATPase inhibition over a range of DCCD concentration suggests that this 97,000 dalton protein is a component of the plasma membrane H+-ATPase. An antibody raised against the plasma membrane H+-ATPase of Neurospora crassa cross-reacted with the 97,000 dalton DCCD-binding protein, further supporting the identity of this protein. Immunoblots of two-dimensional gels of red beet plasma membrane vesicles indicated the isoelectric point of the H+-ATPase to be 6.5. 相似文献
17.
18.
Cytoplasmic acidification and current influx follow growth pulses of
Lilium longiflorum
pollen tubes 总被引:5,自引:1,他引:4
Mark A. Messerli Kenneth R. Robinson 《The Plant journal : for cell and molecular biology》1998,16(1):87-91
We confirm that there is not a standing pH gradient in the tips of lily pollen tubes, but show that there are pulses of H+ that occur during pulsatile growth. The [H+] increases in a zone at the tips of the tubes and travels rapidly as far as 60 μm down the shaft of the tube. The tip-localized pH was found to drop to 6.0 during the largest pulses, from an average cytosolic level of 7.05 in tubes that had not yet begun to pulse. Correlation analysis indicates that the peaks of the pH pulses lag the peaks of the growth pulses by slightly more than 7.5 sec. Vibrating probe measurements reveal an influx of ionic current that peaks 7.5 sec after the peaks of the growth pulses. While this current may in part be H+ influx, we give evidence that K+ influx is also a component of the current pulses. The timing of the H+ and current pulses suggests that they may be involved in terminating the growth pulses. 相似文献
19.
Effect of potassium deficiency on the plasma membrane H+ -ATPase of the wood ray parenchyma in poplar
M. AREND G. MONSHAUSEN C. WIND M. H. WEISENSEEL & J. FROMM 《Plant, cell & environment》2004,27(10):1288-1296
The effect of K+ deficiency on the plasma membrane (PM) H+‐ATPase was studied in young stems of poplar plants (Populus tremula × tremuloides) grown with low or full‐strength K+ supply. Immunological assays using different antibodies were applied to test if K+ deficiency affects the amount of immunodetectable PM H+‐ATPases in the stem tissue. The monoclonal antibody clone 46 E5 B11 revealed an increased abundance of PM H+‐ATPases under conditions of low K+ supply, and immunolabelling experiments showed that this increase was restricted to vessel‐associated cells (VACs) of the wood ray parenchyma. Replacement of the monoclonal antibody by a polyclonal antibody against PM H+‐ATPase gave a specific immunoreactivity on blots as well as tissue sections too, but the labelling intensity showed no difference between plants with low or full‐strength K+ supply. Measurements of extracellular H+ concentrations using non‐invasive, H+‐selective microelectrodes revealed a lowering of the pH at the surface of VACs and an enhancement of net efflux of H+ in plants grown with low K+ supply. The present results indicate an up‐regulation of specific isoforms of the PM H+‐ATPase in VACs under K+‐deficient conditions and suggest a key role for these PM H+‐ATPases in unloading K+ from the xylem stream. 相似文献
20.
Ya-Ya Shi Wen-Jing Tao Shu-Ping Liang Yingtang Lü Lei Zhang 《Plant cell reports》2009,28(8):1253-1264
Ca2+-CaM signaling is involved in pollen tube development. However, the distribution and function of CaM and the downstream components
of Ca2+-CaM signal in pollen tube development still need more exploration. Here we obtained the CaM–GFP fusion protein transgenic
line of Nicotiana tobacum SRI, which allowed us to monitor CaM distribution pattern in vivo and provided a useful tool to observe CaM response to various
exogenous stimulations and afforded solid evidences of the essential functions of CaM in pollen tube growth. CaM–GFP fusion gene was constructed under the control of Lat52-7 pollen-specific promoter and transformed into Nicotiana tobacum SRI. High level of CaM–GFP fluorescence was detected at the germinal pores and the tip-to-base gradient of fluorescence was
observed in developing pollen tubes. The distribution of CaM at apical dome had close relationship with the pulsant growth
mode of pollen tubes: when CaM aggregated at the apical dome, pollen tubes stepped into growth state; When CaM showed non-polarized
distribution, pollen tubes stopped growing. In addition, after affording exogenous Ca2+, calmidazolium (antagonism of CaM) or Brefeldin A (an inhibitor of membrane trafficking), CaM turned to a uniform distribution
at the apical dome and pollen tube growth was held back. Taken together, our results showed that CaM played a vital role in
pollen tube elongation and growth rate, and the oscillation of tip-to-base gradient of CaM was required for the normal pulsant
growth of pollen tube. 相似文献