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1.
KIYOTA GOSHIMA HACHIRO YAMANAKA GORO EGUCHI SHIGEO YOSHINO 《Development, growth & differentiation》1978,20(2):191-204
Increase in the extracellular Ca2+ concentration from low (≤ 10−7 M) to normal (10−3 M) caused morphological changes of cultured myocardial cells obtained from fetal mouse heart. The extracellular Na+ and K+ concentrations of the normal medium (10−3 M Ca2+ ) did not significantly affect the genesis of these morphological changes. Like Ca2+ , Ba2+ and Sr2+ , but not Mg2+ , Co2+ or Ni2+ , could induce morphological changes. Increase in the extracellular Ca2+ concentration from 10−8 M to 10−3 M also caused excess uptake of 45 Ca2+ by cultured myocardial cells. B–16CW 1 cells, which did not show these morphological changes, did not take up excess 45 Ca2+ on this treatment. Treatments, such as addition of verapamil or incubation at pH 6.3, which reduced the genesis of morphological changes, reduced the rate of 45 Ca2+ uptake by myocardial cells. These facts show that the morphological changes of myocardial cells induced by increasing the extracellular Ca2+ concentration from low to normal are due to excess uptake of Ca2+ by the myocardial cells.
The morphological changes of cultured myocardial cells induced by increasing the extracellular Ca2+ concentration from low to normal were reversed on further incubation of the cells in medium with or without Ca2+ . 相似文献
The morphological changes of cultured myocardial cells induced by increasing the extracellular Ca
2.
Terence M. Murphy 《Physiologia plantarum》1988,74(3):537-543
A low fluence of ultraviolet radiation (UV) causes cultured cells of Rosa damascena Mill cv. Gloire de Guilan to lose intracellular K+ . This effect required the presence of Ca2+ in the medium. A reduction in the concentration of free Ca2+ to 10−5 M with ethyleneglycol-bis-(β-aminoethyl-ether)-N.N.N',N'-tetraacetic acid (EGTA) buffer inhibited the UV-stimulated efflux; this was correlated with a discharge of the membrane potential and a stimulation of the leakage of K+ from unirradiated cells. All the same effects were seen with La3+ at 0.2 m M. At 0.02 m M La3+ , the UV-stimulated efflux of K+ was blocked without concomitant effects on the membrane potential or K+ efflux from control cells. It is suggested that removal of Ca2+ blocks or masks the UV-induced leakage of K+ by destabilizing the plasma membrane. In addition, La3+ may specifically inhibit the UV-stimulated opening of K+ or anion channels. 相似文献
3.
V. Niggli D. E. Knight P. F. Baker A. Vigny† J.-P. Henry† 《Journal of neurochemistry》1984,43(3):646-658
Abstract: The systems responsible for phosphorylating tyrosine hydroxylase, the rate-limiting enzyme of catecholamine biosynthesis, were investigated in situ in adrenal medullary cells made permeable to solutes of up to 1,000 dalton by exposure to brief intense electric fields. Two different phosphorylation systems were found. One is dependent on Ca2+ , the other on cyclic AMP. The Ca2+ -dependent system is half-maximally activated by 1-2 μ M Ca2+ and 0.5 m M ATP, and follows a time course similar to that of secretion of catecholamines. Trifluoperazine (0.1 m M ) does not inhibit significantly Ca2+ -dependent phosphorylation of tyrosine hydroxylase in situ. The cyclic AMP-dependent system is half-maximally activated by addition of 0.5 μ M cyclic AMP and about 0.3 m M ATP. Ca2+ -dependent and cyclic AMP-dependent phosphorylations of tyrosine hydroxylase have roughly the same time course and are additive under conditions where one system is already saturated. Peptide maps of immunoprecipitated tyrosine hydroxylase, after in situ phosphorylation of the enzyme either in the presence of 10−8 M Ca2+ plus 2 × 10−5 M cyclic AMP or of 10−5 M Ca2+ , show a marked difference indicating that the enzyme contains several phosphorylation sites. At least one of these sites is phosphorylated only by the Ca2+ -dependent system, whereas the other site(s) are phosphorylated by both the Ca2+ - and cyclic AMP-dependent systems. The effect of in situ phosphorylation of tyrosine hydroxylase on its enzymatic activity was also investigated. 相似文献
4.
Effect of auxins on spermidine uptake into carrot protoplasts 总被引:1,自引:0,他引:1
Malee Kanchanapoom Fabiana Antognoni Rossella Pistocchi Nello Bagni 《Physiologia plantarum》1991,82(1):19-23
The effect of an auxin, indole-3-acetic-acid (IAA), on spermidine uptake into protoplasts of carrot ( Daucus carota L. cv. Ingrid) was studied. In the presence of 1 m M Ca2+ , IAA (10−7 to 10−4 M ) enchances [14 C]-spermidine uptake into carrot protoplasts, while no stimulation occurs in the absence of Ca2+ . The time course of the uptake with and without IAA is very rapid and reaches saturation within 1 to 2 min. Preincubation of protoplasts with IAA inhibits the spermidine uptake. La3+ , known not to penetrate the plasmalemma, exerts the same effect as Ca2+ , but gives lower uptake values than Ca2+ . The application of vanadate, an ATPase inhibitor, strongly inhibits IAA-stimulated spermidine uptake, suggesting that an energy-dependent mechanism may be involved in this transport. Neither spermidine nor Ca2+ alone stimulate IAA uptake. The synthetic auxin 2,4-dichlorophenoxyacetic acid, yields the same results as IAA with regard to time course of spermidine uptake with and without preincubation while, unlike IAA, no significant effect was observed on the Ca2+ -induced increase of spermidine uptake. 相似文献
5.
Toshio Matsuda Kazuhiro Takuma Shoichi Asano Yoko Kishida Hiroaki Nakamura Koichi Mori †Sadaaki Maeda Akemichi Baba 《Journal of neurochemistry》1998,70(5):2004-2011
Abstract: The Ca2+ /calmodulin-dependent phosphatase calcineurin may have physiological and pathological roles in neurons, but little is known about the roles of the enzyme in glial cells. We have previously reported that reperfusion of cultured astrocytes in Ca2+ -containing medium after exposure to Ca2+ -free medium caused Ca2+ influx followed by delayed cell death. In this study, we examined if calcineurin is involved in this Ca2+ -mediated astrocytic injury. FK506, an inhibitor of calcineurin, protected cultured rat astrocytes against paradoxical Ca2+ challenge-induced injury in a dose-dependent manner (10−10 –10−8 M ). Cyclosporin A at 1 µ M mimicked the effect of FK506. Rapamycin (1 µ M ) did not affect astrocyte injury, but it blocked the protective effect of FK506. Deltamethrin (20 n M ), another calcineurin inhibitor, had a similar protective effect, whereas okadaic acid did not. FK506 affected neither paradoxical Ca2+ challenge-induced increase in cytosolic Ca2+ level nor Na+ -Ca2+ exchange activity in the cells, suggesting that the calcineurin is involved in processes downstream of increased cytosolic Ca2+ level. Immunochemical studies showed that both calcineurin A (probably the Aβ2 isoform) and B subunits were expressed in the cells. It is concluded that calcineurin is present in cultured astrocytes and it has a pathological role in the cells. 相似文献
6.
Manuel A. Vega Eduardo C. Santamaria Alfonsina Morales Ricardo L. Boland 《Physiologia plantarum》1985,65(4):423-426
Vitamin D3 at low concentration (10−9 M) inhibited the growth of Phaseolus vulgaris L. (cv. Contrancha) roots in vitro as measured by elongation (14 h) and [3 H]-leucine incorporation into protein (2 h), and increased their labelling with 45 Ca2+ (2 h). Cycloheximide and puromycin (50 u.M) blocked vitamin D3 stimulation of root 45 Ca2+ labelling, indicating that it is mediated by de novo protein synthesis. The calcium ionophore X-537A (10−5 JW) induced similar changes both in root elongation and 45 Ca2+ uptake (14 h). This may indicate that the inhibitory effects of the sterol on root growth are mediated by changes in Ca2+ fluxes. However, this interpretation should be further strengthened by additional studies as the ionophore may have acted on root growth, affecting physiological processes other than Ca2+ transport. 相似文献
7.
SAXITOXIN TETRODOTOXIN AND THE METABOLISM AND CATION FLUXES IN ISOLATED CEREBRAL TISSUES 总被引:2,自引:0,他引:2
Abstract— Saxitoxin and tetrodotoxin at low concentrations (10−7 -10−8 M) exerted similar inhibitory effects on the increase in lactate production and the redistrjbution of Na+ and K+ that normally accompany electrical stimulation of rat cerebral cortical slices. In contrast, the toxins exerted dissimilar effects on the production of lactate in response to low concentrations of Ca2+ in the medium. Inhibition by tetrodotoxin occurred at a higher concentration of Ca2+ and was significantly greater than that produced by saxitoxin at concentrations of Ca2+ below 0.75 mM. These differences were not related to differential effects on the redistribution of Na+ and K+ under such conditions. The toxins had different effects on Ca2+ influx. Tetrodotoxin, but not saxitoxin, inhibited the influx of Ca2+ in the absence of electrical stimulation. The influx of Ca2+ increased when electrical pulses were applied and tetrodotoxin inhibited this increase, whereas saxitoxin potentiated influx of Ca2+ during stimulation. Our results suggest that metabolic responses to conditions that increase excitability are not governed solely by changes in the distribution of Na+ and K+ . The differential effects of the toxins on Ca2+ fluxes suggest that one site of Ca2+ entry during electrical stimulation may be functionally independent of Na+ entry. 相似文献
8.
Calcium ion transport across discs of the cortical flesh of apple fruit in relation to fruit development 总被引:3,自引:0,他引:3
Transport of Ca2+ through discs of apple fruit tissue was examined in tissue taken at different stages of fruit development. Transport rates decreased with fruit development when cation exchange was the predominant influence on transport (with 10−6 M 45 CaCl2 as the source solution). This decrease was associated with a reduction in relative cell wall surface area, cation exchange capacity and cell wall yield that occurred during fruit growth. When diffusion was the major transport force, and when transport was influenced by solution infiltration of the tissue disc (10−2 M 45 CaCl2 in the source solution), transport rates increased during fruit growth. This increment was related to increases in air space of the tissue. Ca2+ transport through apple fruit tissue is influenced by the extent and nature of the cell wall, changing proportions of air space and Ca2+ concentration in the extracellular solution. 相似文献
9.
Abstract: The effect of dopamine (DA) receptor stimulation on the distribution of γ protein kinase C (γPKC) in hippocampal slices was assessed. Nanomolar concentrations of DA decreased cytosolic γPKC (56%) without altering membrane γPKC levels, resulting in decreased total γPKC immunoreactivity. The maximal decrease in cytosolic γPKC occurred at 20 min of incubation and was significantly blocked by the D1 DA antagonist SCH 23390 (10−6 M ) but not by the D2 antagonist sulpiride (10−5 M ). The D1 agonists SKF 38393 and A 77636 mimicked the effect of DA with similar responses produced at 10 µ M and 1 n M , respectively. The D2 agonist quinpirole had no effect on γPKC immunoreactivity, thus indicating that this dopaminergic response is mediated through a D1 -like receptor. DA had no effect on α, δ, or ζPKC isozyme immunoreactivity in the same hippocampal preparations. The DA-induced decrease in cytosolic γPKC immunoreactivity was blocked by the Ca2+ -dependent protease inhibitor N -acetyl-Leu-Leu-norleucinal (100 µ M ) and by the inorganic Ca2+ channel blocker Co2+ . The data suggest that DA stimulates a D1 -like DA receptor, which increases the influx of Ca2+ and activates the Ca2+ -dependent proteolysis of γPKC. 相似文献
10.
Extracellular Calcium Has Distinct Effects on Fast and Slow Components of the Depolarization-Induced Secretory Response from Chromaffin Cells 总被引:1,自引:0,他引:1
R. Granja V. Izaguirre S. Calvo C. González-García V. Ceña 《Journal of neurochemistry》1996,67(3):1056-1062
Abstract: An increase in extracellular Ca2+ concentration from 0.25 to 10 m M enhanced secretion of norepinephrine and epinephrine induced by a high extracellular K+ concentration (75 m M ). The increment in extracellular Ca2+ concentration also increased the observed peak inward Ca2+ current in response to long (10-s) depolarizing pulses from a holding potential of −55 mV to +5 mV, from about −26 to −400 pA. However, the total amount of Ca2+ influx into the cell only increased when the extracellular Ca2+ concentration was raised from 0.25 to 1 m M and then remained constant up to 10 m M extracellular Ca2+ . ATP is cosecreted with catecholamines following a depolarizing stimulus. Kinetic studies indicated that ATP secretion had two components with time constants, in the presence of 2.5 m M extracellular Ca2+ , of ∼4 and 41 s, being the fast component of secretion produced by the exocytosis of ∼220 chromaffin granules. The results suggest that, for a given depolarizing stimulus, the size and rate of release for the fast and slow components of secretion are dependent on extracellular Ca2+ concentration. 相似文献
11.
Abstract: We investigated the interaction between Pb2+ and protein kinase C (PKC) in the Pb2+ -induced release of norepinephrine (NE) from permeabilized adrenal chromaffin cells. Our analysis of endogenous PKC activity in permeabilized cells suggests that Pb2+ interacts with the adrenal enzyme at multiple sites. Pb2+ activates the enzyme through high-affinity ( K A(Pb) = 2.4 × 10−12 M ) interactions and inhibits the enzyme by competitive and noncompetitive interactions with nanomolar-( K i = 7.1 × 10−9 M ) and micromolar- ( K 'i = 2.8 × 10−7 M ) affinity sites, respectively. Activation of PKC by 12- O -tetradecanoylphorbol 13-acetate (TPA) in Ca2+ -deficient, Pb2+ -containing medium, enhances the Pb2+ -induced NE release from permeabilized chromaffin cells by lowering the concentration of Pb2+ required for half-maximal activation of the secretory response from 7.5 × 10−10 to 5.7 × 10−11 M . The PKC inhibitors staurosporine and pseudosubstrate PKC (19–36) abolish the effect of TPA without affecting the Pb2+ -induced secretion in the absence of TPA. These results indicate that (a) Pb2+ is a partial agonist of PKC, capable of both activating and inhibiting the enzyme and (b) synergistic activation of PKC by TPA and Pb2+ results in increased sensitivity of exocytosis to Pb2+ but is not obligatory for Pb2+ -triggered secretion. 相似文献
12.
Protein Synthesis in a Cell-free System from Rat Brain Sensitive to ACTH-like Peptides 总被引:2,自引:2,他引:0
Abstract: Protein synthesis was measured using a cell-free system obtained from subcortical rat brain tissue. The concentrations of Mg2+ and K+ and the amount of tissue, during both the preparation and the final assay, were critical to the incorporation of amino acids as expressed per milligram protein. Even under optimal conditions mainly elongation of growing peptide chains was measured. Behaviorally active fragments of ACTH modulated the activity of the system in a biphasic manner; i.e., at a low concentration (10−8 M) of ACTH a stimulation of between 10 and 70% was found; a high concentration (10−4 M) was inhibitory (50 to 70%). Structure-activity studies revealed that the stimulatory effect was confined to the N-terminus of the peptide (1–24), whereas the C-terminal sequence was responsible for the inhibition. The stimulation by ACTH1–24 was dependent on Ca2+ and Mg2+ . Cyclic AMP (10−5 M) stimulated the amino acid incorporation too. When a similar cell-free extract was prepared from brain tissue of hypophysectomized rats, the lower in vivo protein synthesis in these animals was preserved in the present cell-free system. The data are discussed in terms of a possible direct intracellular effect of ACTH on brain protein synthesis. 相似文献
13.
Abstract— Synthetic substance P initially increased cyclic AMP levels and subsequently induced neurite extension in cultured neuroblastoma N 18 cells. The magnitude of these effects depended on the concentration of fetal calf serum (FCS) in the culture medium, being more evident in the presence of a lower (0.1%) concentration of FCS.
In Eagle's medium containing 0.1% FCS, low concentrations of substance P (10−7 -10−5 M) increased cyclic AMP levels and stimulated neurite extension.
In Eagle's medium containing 5%FCS, both substance P at concentrations of 10−5 -10−3 M and dibutyryl cyclic AMP at concentrations of 10−4 -10−2 M increased cyclic AMP levels and stimulated neurite extension. The activities of acetylcholinesterase, (Na+ + K+ )-, HCO3 − and Mg2+ -stimulated-ATPase were also increased. Cell growth was inhibited.
Substance P at concentrations of 10-7 -10−5 M also stimulated the adenylate cyclase activity of a particulate fraction of N 18 in a concentration-dependent manner. 相似文献
In Eagle's medium containing 0.1% FCS, low concentrations of substance P (10
In Eagle's medium containing 5%FCS, both substance P at concentrations of 10
Substance P at concentrations of 10-
14.
Preference responses of zebrafish to 10−3 , 10−4 and 10−5 M alanine (Ala) were concentration- dependent. Behavioural responses to copper (Cu) and Cu + Ala mixtures were also assessed. Zebrafish avoided 100 and 10 μg Cu l−1 , but not 1 μg l−1 . Mixtures of 10−3 m Ala+ 100 μg Cu l−1 and 10 4 M Ala + 10 μg Cu 1−1 were avoided as intensely as was Cu alone. Responses to 10−3 M Ala + 10 or 1 μg Cu l−1 and 10 4 M Ala +1 μg Cu l−1 did not differ statistically from controls (no detectable preference or avoidance). These results demonstrate, firstly, that a concentration of a pollutant avoided by itself (10 μg Cu l−1 ) may not be avoided when encountered with an attractant chemical stimulus (Ala) and may suppress the preference for an attractant stimulus, and secondly, that a concentration of a pollutant not avoided by itself and not considered deleterious (1 μg Cu l−1 ) suppresses attraction to Ala (an important constituent of prey odours for many fishes). 相似文献
15.
Recent studies have suggested that Ca2+ /calmodulin (CaM) or CaM-like proteins may be involved in blue light (BL)-dependent proton pumping in guard cells. As the increase in cytosolic concentration of Ca2+ is required for the activation of CaM and CaM-like proteins, the origin of the Ca2+ was investigated by measuring BL-dependent proton pumping with various treatments using guard cell protoplasts (GCPs) from Vicia faba . BL-dependent proton pumping was affected neither by Ca2+ channel blockers nor by changes of Ca2+ concentration in the medium used for the GCPs. Addition of Ca2+ ionophores and an agonist to GCPs did not induce proton pumping. However, BL-dependent proton pumping was inhibited by 10 m M caffeine, which releases Ca2+ from the intracellular stores, and by 10 μ M 2,5-di-( tert -butyl)-1,4-benzohydroquinone (BHQ) and 10 μ M cyclopiazonic acid (CPA), inhibitors of Ca2+ -ATPase in the sarcoplasmic and endoplasmic reticulum (ER). By contrast, the inhibitions were not observed by 10 μ M thapsigargin, an inhibitor of animal ER-type Ca2+ -ATPase. The inhibitions by caffeine and BHQ were reversible. Light-dependent stomatal opening in the epidermis of Vicia was inhibited by caffeine, BHQ, and CPA. From these results, we conclude that the Ca2+ thought to be required for BL-dependent proton pumping may originate from intracellular Ca2+ stores, most likely from ER in guard cells, and that this origin of Ca2+ may generate a stimulus-specific Ca2+ signal for stomatal opening. 相似文献
16.
EVIDENCE FOR CALCIUM-SENSITIVE COMPONENT IN BRAIN ACTOMYOSIN-LIKE PROTEIN (NEUROSTENIN) 总被引:2,自引:1,他引:1
Abstract— The isolation of brain actomyosin-like protein (neurostenin) with a Ca2+ -sensitive component is described. The addition of 1 m m EGTA results in approximately 50 per cent reduction in MgATPase activity. The inhibition can be released by a free Ca2+ concentration of 10−6 m . Dialysis of the protein complex against low ionic strength medium followed by centrifugation results in a loss of Ca2+ sensitivity in the pelleted protein. Ca2+ sensitivity can be restored by reprecipitating this desensitized complex in the presence of the 70.000 g supernatant. The protection of sulphhydryl groups during desensitization and reconstitution procedures is essential. This Ca2+ regulatory property is similar, in these respects, to other actomyosin-like proteins. 相似文献
17.
Tomoyoshi Uchikawa Yuji Kiuchi Akihiko Yura Noriyuki Nakachi Yukako Yamazaki Chie Yokomizo Katsuji Oguchi 《Journal of neurochemistry》1995,65(5):2065-2071
Abstract: We studied effects of Ca2+ in the incubation medium on [3 H]dopamine ([3 H]DA) uptake by rat striatal synaptosomes. Both the duration of the preincubation period with Ca2+ (0–30 min) and Ca2+ concentration (0–10 m M ) in Krebs-Ringer medium affected [3 H]DA uptake by the synaptosomes. The increase was maximal at a concentration of 1 m M Ca2+ after a 10-min preincubation (2.4 times larger than the uptake measured without preincubation), which reflected an increase in V max of the [3 H]DA uptake process. On the other hand, [3 H]DA uptake decreased rapidly after addition of ionomycin in the presence of 1 m M Ca2+ . The Ca2+ -dependent enhancement of the uptake was still maintained after washing synaptosomes with Ca2+ -free medium following preincubation with 1 m M Ca2+ . Protein kinase C inhibitors did not affect apparently Ca2+ -dependent enhancement of the uptake, whereas 1-[ N,O -bis(1,5-isoquinolinesulfonyl)- N -methyl- l -tyrosyl]-4-phenylpiperazine (KN-62; a Ca2+ /calmodulin-dependent kinase II inhibitor) and wortmannin (a myosin light chain kinase inhibitor) significantly reduced it. Inhibitory effects of KN-62 and wortmannin appeared to be additive. N -(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7; a calmodulin antagonist) also remarkably inhibited the enhancement. These results suggest that Ca2+ -dependent enhancement of [3 H]DA uptake is mediated by activation of calmodulin-dependent protein kinases. 相似文献
18.
Abstract: Cross talk between two phospholipase C (PLC)-linked receptor signalings was investigated in SK-N-BE(2)C human neuroblastoma cells. Sequential stimulation with two agonists at 5-min intervals was performed to examine the interaction between muscarinic and bradykinin (BK) receptors. Pretreatment of cells with a maximal effective concentration (5 µ M ) of BK did not affect the subsequent carbachol (CCh)-induced [Ca2+ ]i rise, but CCh (1 m M ) pretreatment completely abolished the BK-induced [Ca2+ ]i rise without inhibition of BK-induced inositol 1,4,5-trisphosphate (IP3 ) generation. Thapsigargin (1 µ M ) pretreatment abolished the subsequent BK- and CCh-induced [Ca2+ ]i rise, though it did not affect agonist-induced IP3 generation. However, the addition of atropine at plateau phases of CCh-induced [Ca2+ ]i rise and IP3 production caused a rapid decline to the basal levels and then restored the [Ca2+ ]i rise by BK. Treatment of cells with both CCh and BK at the same time showed additive effects in IP3 production. However, the [Ca2+ ]i rise induced by both agonists in the presence or absence of extracellular Ca2+ was the same as the responses triggered by CCh alone. The results suggest that each receptor or receptor-linked PLC activity is not influenced by pretreatment with the other agonist but IP3 -sensitive Ca2+ stores are shared by signal pathways from both receptors. 相似文献
19.
Some classes of marine phytoplankton are believed to be more tolerant of high concentrations of trace metals than others, but the results of experimental tests of this hypothesis are ambiguous. Eleven species of phytoplankton representing five classes were grown in Aquil medium containing Cd concentrations between 10−8 and 10−5 M ([Cd2+ ]= 10−9.85 to 10−6.84 M), and growth rates and intracellular concentrations of Cd, C, N, and S were measured. The mean Cd2+ concentration (pCd50 ) that reduced the growth rate of each species to 50% of its maximum varied by 2.5 orders of magnitude, from 10−6.23 for Emiliania huxleyi to 10−8.79 for Synechococcus sp. Taxonomic trends in Cd resistance were not apparent in these data. Cadmium quotas (mol Cd·L−1 cell volume) were lowest in species of Bacillariophyceae (ANOVA, P < 0.001), suggesting that they might regulate Cd transport differently than other taxa. Cellular S:C molar ratios increased in four of seven phytoplankton grown at high pCd (7.37–6.84) compared to low Cd ion concentrations (no added Cd), a result of increases in S·L−1 cell volume. Nitrogen:carbon molar ratios were also higher in Cd-exposed phytoplankton, as changes in N and S were highly correlated ( r = 0.98, P < 0.0001). In two species that were examined, S:C ratios increased as a linear function of increasing Cd concentration. The results demonstrate large variability in Cd resistance among phytoplankton that is primarily a function of interspecific differences in Cd detoxification. 相似文献
20.
Seed dimorphism in Salicornia europaea: Nutrient reserves 总被引:1,自引:0,他引:1
Franz-Arnold Austenfeld 《Physiologia plantarum》1988,73(4):502-504
Median and lateral seeds of Salicornia europaea L. were separately analysed for their sizes and nutrient reserves. The mean air-dry weight of a single median and lateral seed was 0.31 and 0.25 mg, respectively. The composition as well as the concentration of the nutrient reserves were similar in both seed types. The bulk of the cations was derived from K+ , followed by Mg2+ , Na+ and Ca2+ . The chloride content was somewhat higher than the sodium content, and phosphate was equalled by acid soluble Ca2+ and Mg2+ . Starchy compounds and sucrose were present in equal amounts, each of them accounted for about 50% of the carbohydrates. Glucose and fructose were less than 1%. Protein-nitrogen (ethanol-insoluble N) was about 34 g (kg dry seeds)−1 . About 7 g (kg dry seeds)−1 was ethanol-soluble nitrogen, of which 10% was derived from amino acids. The total lipid content was more than 290 g (kg dry seeds)−1 , 65% were calculated to be glycerides. More than 90% of the fatty acids consisted of linoleic and oleic acids, the majority (72%) of which was linoleic acid. 相似文献