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1.
A technique is described that allows a relatively rapid and controlled isolation of vacuoles from leaves of the crassulacean acid metabolism (CAM) plant Kalanchoë daigremontiana. The method involves polybase-induced lysis of mesophyllcell protoplasts and isolation of vacuoles on a discontinuous density gradient. ATPase activity is associated with the isolated vacuoles and is not attributable to contamination by cytoplasmic constituents. It is suggested that this ATPase is responsible for the energization of malic-acid accumulation in the vacuole in CAM plants.Abbreviation CAM
crassulacean acid metabolism
Dedicated to Professor Dr. W. Simonis on the occasion of his 75th birthday 相似文献
2.
3.
Summary In the CAM plant Kalanchoë daigremontiana, kept in an environmental rhythm of 12 h L: 12 h D in a growth chamber at 60% relative humidity and well watered in the root medium, decreasing water potentials and osmotic potentials of the leaves are correlated with malate accumulation in the dark. In the light increasing water and osmotic potentials (
W
and
S
) are associated with decreasing malate levels. Transpiratory H2O loss is high in dark and low in light.In continuous light, the CAM rhythm rapidly disappears in the form of a highly damped endogenous oscillation. Malate levels, and water and osmotic potentials of the leaves remain correlated as described above. However, transpiration is very high as malate levels decrease and water and osmotic potentials increase.It can concluded, that water relation parameters like total water potential (
W
) and osmotic potential (
S
) change in close correlation with changes of malic acid levels. As an important osmotically active solute in CAM plants, malic acid appears to affect water relations independently of and in addition to transpiration. The question remains open, whether turgor (
P
) is involved in CAM regulation in intact plants in a similar way as it determines malate fluxes in leaf slices.Abbreviations CAM
Crassulacean Acid Metabolism
- L
Light
- D
Dark 相似文献
4.
Malate Decarboxylation by Kalanchoë daigremontiana Mitochondria and Its Role in Crassulacean Acid Metabolism
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Day DA 《Plant physiology》1980,65(4):675-679
Mitochondria isolated from Kalanchoë daigremontiana, a Crassulacean acid metabolism plant, decarboxylate added malate to pyruvate at rates of up to 100 micromoles per hour per milligram original chlorophyll in the presence of ADP. Omitting ADP reduces this rate by approximately 50%. Antimycin A inhibits malate decarboxylation and this inhibition could be relieved by addition of aspartate and α-ketoglutarate to the mitochondria. Increasing the pH of the external medium inhibited malate decarboxylation; a dramatic decrease in pyruvate production was observed between pH 7.2 and pH 7.4. It is suggested that cytoplasmic pH changes may regulate the contribution of mitochondria to malate decarboxylation in the light in vivo. 相似文献
5.
The crassulacean acid metabolism (CAM) plant Kalancho? daigremontiana Hamet et Perrier de la Bathie shows an endogenous circadian rhythm of net CO2 exchange (J
CO2
) under constant conditions in continuous light. Previous studies have shown, however, that above a certain threshold temperature
J
CO2
changes from rhythmic to arrhythmic behaviour and that this is reversible when the temperature is lowered again. It is now
demonstrated here, that this re-initiation of rhythmic J
CO2
from arrhythmicity needs a sufficiently strong temperature signal as defined by its abruptness. Rhythmicity reappears only
if the temperature is reduced rather rapidly. If the temperature is reduced slowly then arrhythmicity is retained even at
a low temperature level which normally would allow rhythmicity. Under these circumstances, however, a distinct temperature
increase followed by an abrupt temperature decrease immediately elicits regular oscillations of J
CO2
at this lower temperature. We suggest that the strong temperature signals function as a definite synchronizer (“zeitgeber”)
which synchronizes different cells and/or different leaf areas which remain desynchronized after application of only slow
temperature changes. This is further supported by Fourier transform analyses, revealing a harmonic structure of the superficially
arrhythmic time series of J
CO2
after application of slow temperature reductions. This conclusion adds a spatial dimension to the otherwise purely time-dependent
rhythmicity and arrhythmicity of J
CO2
in CAM.
Received: 18 May 1998 / Accepted: 30 June 1998 相似文献
6.
During the endogenous circadian rhythm of carbon dioxide uptake in continuous light by a Crassula cean acid metabolism plant, Kalancho? daigremontiana, the two carboxylating enzymes, phosphoenolpyruvate carboxylase (PEPC) and ribulose 1,5 bisphosphate carboxylase/oxygenase (Rubisco), are active simultaneously, although, until now, only the role of PEPC in generating the rhythm has been acknowledged. According to the established model, the rhythm is primarily regulated at the PEPC activity level, modulated by periodic compartmentation of its inhibitor, malate, in the vacuole and controlled by tension/relaxation of the tonoplast. However, the circadian accumulation of malic acid (the main indicator of PEPC activity) dampened significantly within the first few periods without affecting the rhythm's amplitude. Moreover, the amount of malate accumulated during a free-running oscillation was several-fold lower than the amount expected if PEPC were the key carboxylating enzyme, based on a 1:1 stoichiometry of CO(2) and malate. Together with the observation that rates of CO(2) uptake under continuous light were higher than in darkness, the evidence shows that C(3) carboxylation greatly contributes to the generation of rhythmic CO(2) uptake in continuous light in this 'obligate' CAM plant. Because the shift from predominantly CAM to predominantly C(3) carboxylation is smooth and does not distort the trajectory of the rhythm, its control probably arises from a robust network of oscillators, perhaps also involving stomata. 相似文献
7.
A study was made of the day-night changes under controlled environmental conditions in the bulk-leaf water relations of Kalanchoë daigremontiana, a plant showing Crassulacean acid metabolism. In addition to nocturnal stomatal opening and net CO2 uptake, the leaves of well-watered plants showed high rates of gas exchange during the whole of the second part of the light period. Measurements with the pressure chamber showed that xylem tension increased during the night and then decreased towards a minimum at about midday; a significant increase in xylem tension was also seen in the late afternoon. Cell-sap osmotic pressure paralleled leaf malate content and was maximum at dawn and minimum at dusk. The relationship between these two variables indicated that the nocturnally synthesized malate was apparently behaving as an ideal osmoticum. To estimate bulk-leaf turgor pressure, values for water potential were derived by correcting the pressurechamber readings for the osmotic pressure of the xylem sap. This itself was found to depend on the malate content of the leaves. Bulk-leaf turgor pressure changed rhythmically during the day-night cycle; turgor was low during the late afternoon and for most of the night, but increased quickly to a maximum of 0.20 MPa around midday. In water-stressed plants, where net CO2 uptake was restricted to the dark period, there was also an increase in bulk-leaf turgor pressure at the start of the light period, but of reduced magnitude. Such changes in turgor pressure are likely to be of considerable ecological importance for the water economy of crassulacean-acid-metabolism plants growing in their natural habitats.Abbreviation and symbols CAM
Crassulacean acid metabolism
-
P
turgor pressure
-
osmotic pressure
-
water potential
Dedicated to Professor Dr. H. Ziegler on the occasion of his 60th birthday 相似文献
8.
Stimulation of CAM Photosynthesis in Kalanchoë blossfeldiana by Transferring to Nitrogen-Deficient Conditions
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Ota K 《Plant physiology》1988,87(2):454-457
Kalanchoë blossfeldiana Poelln. cv Hikan plants were grown hydroponically with nutrient solution containing 5 millimolar NO3− (or NH4+) for 1 to 2 months and then transferred to nutrient solution containing no nitrogen. CO2 uptake at night, nocturnal increase in titratable acidity, and activity of phosphoenolpyruvate carboxylase increased after the transfer. Thus, transfer to nitrogen-deficient conditions stimulates Crassulacean acid metabolism (CAM photosynthesis) in K. blossfeldiana. The importance of the plant nitrogen status (nitrogen-withdrawal status) for induction and stimulation of CAM photosynthesis is discussed. 相似文献
9.
Tonoplast vesicles were prepared from leaf mesophyll homogenates of the crassulacean-acid-metabolism plant Kalanchoë daigremontiana Hamet et Perrier de la Bâthie to study the effects of anions on ATP- and inorganic-pyrophosphate (PPi)-dependent H+ transport. In the presence of gramicidin, substrate hydrolysis by the tonoplast ATPase was characteristically stimulated by chloride and inhibited by nitrate, but was unaffected by malate and a wide range of other organic-acid anions; the PPiase was anion-insensitive. Malate was more effective than chloride both in stimulating ATP- and PPi-dependent vesicle acidification (measured as quinacrine-fluorescence quenching) and in dissipating a pre-existing inside-positive membrane potential (measured as oxonol-V-fluorescence quenching), indicating that malate was more readily transported across the tonoplast. Certain other four-carbon dicarboxylates also supported high rates of vesicle acidification, their order of effectiveness being fumarate malate -succinate > oxalacetate - tartrate; the five-carbon dicarboxylates 2-oxoglutarate and glutarate were also transported, although at lower rates. Experiments with non-naturally occurring anions indicated that the malate transporter was not stereospecific, but that it required the trans-carboxyl configuration for transport. Shorter-chain or longer-chain dicarboxylates were not transported, and neither were monocarboxylates, the amino-acid anions aspartate and glutamate, nor the tricarboxylate isocitrate. The non-permeant anions maleate and tartronate appeared to be competitive inhibitors of malate transport but did not affect chloride transport, indicating that malate and chloride influx at the tonoplast might be mediated by separate transporters.Abbreviations BTP
1,3-bis-[tris(hydroxymethyl)methylamino]-propane
- CAM
crassulacean acid metabolism
- oxonol V
bis(3-phenyl-5-oxoisoxazol-4-yl)pentamethine oxonol
- pH
transmembrane pH difference
- PPi
inorganic pyrophosphate
- PPiase
inorganic pyrophosphatase
- quinacrine
6-chloro-9-{[4-(diethylamino)-1-methylbutyl]amino}-2-methoxyacridine dihydrochloride
-
transmembrane electrical potential difference 相似文献
10.
Changes in Metabolite Levels in Kalanchoë daigremontiana and the Regulation of Malic Acid Accumulation in Crassulacean Acid Metabolism
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Changes in glucose-6-P, fructose-6-P, fructose-1,6-diP, 6-phospho-gluconate, phosphoenolpyruvate, 3-phosphoglycerate, and pyruvate levels in the leaves of the Crassulacean plant Kalanchoë daigremontiana Hammet et Perrier were measured enzymically during transitions from CO2-free air to air, air to CO2-free air, and throughout the course of acid accumulation in darkness. The data are discussed in terms of the involvement of phosphoenolpyruvate carboxylase in malic acid synthesis and in terms of the regulation of the commencement of malic acid synthesis and accumulation through the effects of CO2 on storage carbohydrate mobilization and its termination through the effects of malic acid on phosphoenolpyruvate carboxylase activity. 相似文献
11.
J. M. Daly S. M. Evans Janet Morley 《Marine and Freshwater Behaviour and Physiology》2013,45(1-4):49-69
Spacing between individuals in populations of Harmothoë imbricata has been investigated both on the shore and in the laboratory. Males tend to occur closer together than females, and the mean male‐male individual distance measured was less than the mean distance between females; male—female distances for immature worms were intermediate. When worms mature they pair: the male mounts the female and lies across her dorsal surface. There is evidence that after spawning the members of a pair separate. Contact responses between worms have been investigated in the laboratory. Most encounters between immature worms lead to separation, as a result of one or both worms moving rapidly away from the other or fighting; females show more marked avoidance behaviour than males. The majority of male‐male and female‐female encounters between mature worms also lead to separation but in male‐female encounters the male usually mounts the female. A male which has mounted a female becomes highly aggressive and will attack intruding males but not females. 相似文献
12.
Diurnal Changes in Metabolite Levels and Crassulacean Acid Metabolism in Kalanchoë daigremontiana Leaves
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Diurnal changes in levels of selected metabolites associated with glycolysis, the C3 cycle, C4-organic acids, and storage carbohydrates were analyzed in active Kalanchoë daigremontiana Crassulacean acid metabolism leaves. Three metabolic transition periods occurred each day. During the first two hours of light, nearly all of the metabolite pools underwent transient changes. Beginning at daylight, stomata opened transiently and closed again within 30 minutes; malate synthesis continued for about 1 hour into the light; C3 photosynthesis began within 30 minutes; and net quantities of starch and glucan began to accumulate after 2 hours, continuing linearly throughout the rest of the day. 相似文献
13.
The response of stomata in isolated epidermis to the concentration of CO2 in the gaseous phase was examined in a C3 species, the Argenteum mutant of Pisum sativum, and a crassulacean-acid-metabolism (CAM) species, Kalanchoë daigremontiana. Epidermis from leaves of both species was incubated on buffer solutions in the presence of air containing various volume fractions of CO2 (0 to 10000·10–6). In both species and in the light and in darkness, the effect of CO2 was to inhibit stomatal opening, the maximum inhibition of opening occurring in the range 0 to 360·10–6. The inhibition of opening per unit change in concentration was greatest between volume fractions of 0 and 240·10–6. There was little further closure above the volume fraction of 360·10–6, i.e. approximately ambient concentration of CO2. Thus, although leaves of CAM species may experience much higher internal concentrations of CO2 in the light than those of C3 plants, this does not affect the sensitivity of their stomata to CO2 concentration or the range over which they respond. Stomatal responses to CO2 were similar in both the light and the dark, indicating that effects of CO2 on stomata occur via mechanisms which are independent of light. The responses of stomata to CO2 in the gaseous phase took place without the treatments changing the pH of the buffered solutions. Thus it is unlikely that CO2 elicited stomatal movement by changing either the pH or the HCO
3
–
/CO
3
2-
equilibria. It is suggested that the concentration of dissolved unhydrated CO2 may be the effector of stomatal movement and that its activity is related to its reactivity with amines. 相似文献
14.
15.
The degradation of starch by a protein fraction of Kalanchoë daigremontiana Hamet et Perrier, obtained by ammoniumsulfate precipitation (30–70%), was found to be catalyzed by -and -amylase (EC 3.2.1.1 and EC 3.2.1.2, respectively) and by starch phosphorylase (EC 2.4.1.1). The activity of these enzymes was determined by chromatographic analysis of the reaction products; separation and identification of -amylase was accomplished by heat-inactivation of -amylase and -glucosidase. When the interaction of amylolytic and phosphorolytic enzymes was comparatively studied, it was found that without inorganic phosphorus in the reaction mixture, 14C-starch was converted predominantly to maltose and glucose; supplementation with 1–10 mM orthophosphate (Pi) resulted in an increase in glucose-1-phosphate formation and a concomitant reduction of maltose production. Since the total volume of starch degradation remained approximately constant, Pi apparently inhibits -amylase (Ki about 3 mM Pi). Thus, free Pi in the cell participates in the regulation of starch catabolism, serving as a substrate for starch phosphorylase while simultaneously reducing the production of maltose. With respect to glucan synthesis, adenosinediphosphoglucose--1,4-glucosyltransferase (EC 2.4.1.22), maltose phosphorylase and maltoseglucosyltransferase were also found to be active. The last-named enzyme catalyzes an exchange between dextrins and is considered to provide primer carbohydrates for the synthesis of polyglucans.Abbreviations ADPG
adenosinediphosphoglucose
- G1P
glucose-1-phosphate
- PEG
polyethylenglycol
- PEP
phosphoenolpyruvate
- Pi
orthophosphate 相似文献
16.
Long-Lasting Light Effects in Imbibed Kalanchoë blossfeldiana Seeds in the Presence of Gibberellic Acid
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Two brief red (R) irradiations, separated by 24 hours, given to Kalanchoë blossfeldiana Poelln. cv Feuerblüte seeds, made secondarily dormant by a prolonged dark incubation period on water and transferred to GA3, induce very low germination. Some effect of these irradiations is preserved, however, during a long dark interval in fully imbibed seeds and greatly increases the germination induced by another brief R exposure. This long-lasting light effect is, at 20°C, only lost after a dark interval of about 1 month. It can also be induced by two brief far-red (FR) exposures. Its preservation is temperature-dependent, low temperatures being favorable. Light-induced changes in the ATP-content were demonstrated during preservation and expression of the long-lasting light effect, indicating a long-lasting metabolic change. In seeds with primary dormancy sown on GA3, an analogous long-lasting light effect is induced by one or two brief R or FR irradiations, even when they are given before germination can take place. The presence of GA3, which was shown to induce a very low fluence germination response in Kalanchoë seeds, is required for the occurrence of the long-lasting light effect. The data suggest long-term preservation of some effect(s) of Pfr rather than persistent presence of Pfr itself. 相似文献
17.
Malate Metabolism in the Dark After CO(2) Fixation in the Crassulacean Plant Kalanchoë tubiflora
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The metabolism of [13C]malate was studied in the Crassulacean plant Kalanchoë tubiflora following exposure to 13CO2 for 2 hour intervals during a 16 hour dark cycle. Nuclear magnetic resonance spectroscopy of [13C]malate extracted from labeled tissue revealed that the transient flux of malate to the mitochondria, estimated by the randomization of [4-13C]malate to [1- 13C]malate by fumarase, varied substantially during the dark period. At both 15 and 25°C, the extent of malate label randomization in the mitochondria was greatest during the early and late parts of the dark period and was least during the middle of the night, when the rate of 13CO2 uptake was highest. Randomization of labeled malate continued for many hours after malate synthesis had initially occurred. Internally respired 12CO2 also served as a source of carbon for malate formation. At 15°C, 15% of the total malate was formed from respired 12CO2, while at 25°C, 49% of the accumulated malate was derived from respired 12CO2. Some of the malate synthesized from external 13CO2 was also respired during the night. The proportion of the total [13C]malate respired during the dark period was similar at 15 and 25°C, and respiration of newly formed [13C]malate increased as the night period progressed. These data are discussed with regard to the relative fluxes of malate to the mitochondria and the vacuole during dark CO2 fixation. 相似文献
18.
Manfred Kluge Jeanne Brulfert Didier Ravelomanana Joseph Lipp Hubert Ziegler 《Oecologia》1991,88(3):407-414
Summary The carbon isotope compositions of samples of Kalanchoë species collected at the natural stands in Madagascar were determined. The results suggest that all species of the genus Kalanchoë are capable of crassulacean acid metabolism. The observed 13C values cover the whole range from –10 to –30. This high diversity of the 13C values was found among the species of the genus as well as, in certain cases, within a single species. This suggest that the CAM patterns in Kalanchoë are generally very flexible. The 13C values show a clear correlation with the climate of the habitats from where the samples derived. Values indicative of CO2 fixation taking place exclusively during the night were found in the dry regions of Madagascar, whereas 13C values indicative of mixed CO2 fixation during night and day or of CO2 fixation entirely during the day are distributed in the humid zones. 相似文献
19.
《Plant science》1988,57(1):27-36
Leaves of Kalanchoë daigremontiana were infected with Agrobacterium tumefaciens strain C58 in order to determine the relative contributions of energy-dependent ion uptake to the observed higher solute concentrations in crown-gall tissue compared with unaffected tissue. The tumor tissue exhibited the following characteristics with respect to unaffected tissue: the content of most solutes was much higher: Na+, K+, Cl–, soluble Pi, total N, protein, soluble amino acids, and soluble sugars. Yet NH−4 and starch content was less. Malate did not fluctuate in a typical CAM rhythm and was lower. The respiration rate on a cytoplasmic volume basis was similar. Photosynthetic rates were much lower. The cytoplasmic ATP concentration was even less, while that of NAD(P)H was higher. Electrical membrane potential was lower (− 184 mV tumor vs. − 223 mV control) and was composed of a higher energy-independent component (− 125 vs. − 98 mV) and a smaller energy-dependent component (− 59 vs. − 125 mV). The response of the membrane potential upon addition of neutral, acidic and basic amino acids including the opines octopine and nopaline was similar in both tissue types. It is suggested that the stronger accumulation of solutes in tumor vs. mesophyll cells cannot be due to thermodynamically more favourable conditions at the plasmalemma, but more probably to a hormone-regulated solute transport across the tonoplast. 相似文献
20.
Nitrate Assimilation and Crassulacean Acid Metabolism in Leaves of Kalanchoë fedtschenkoi Variety Marginata
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Chang NK 《Plant physiology》1981,68(2):464-468
The enzymes necessary to assimilate ammonia either via glutamine synthetase and glutamate synthase or via the glutamate dehydrogenase pathways are present in both green and white leaf tissues of Kalanchoë fedtschenkoi. Nitrate reductase activity develops to a maximum in a Crassulacean acid metabolism (CAM) plant canopy before either ribulose 1,5-bisphosphate carboxylase, or phosphoenolpyruvate carboxylase, or CAM. Nitrate reductase also is activated each morning and is inactivated late in the day as in other plants. However, there does not appear to be any direct relationship between nitrate reductase activity and the level of acid, its daily pattern or the amplitude of CAM. Though nitrate reductase is activated maximally each day by light, in Kalanchoë leaves for six days the activity followed a precise daily pattern independent of continuous light or dark. 相似文献