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1.
Lenaldo Muniz de Oliveira Renato Paiva José Raniere Ferreira de Santana Eduardo Alves Rairys Cravo Nogueira Flávia Dionísio Pereira 《In vitro cellular & developmental biology. Plant》2008,44(2):128-135
The role of cytokinins in the differentiation of the photosynthetic apparatus in micropropagated plants and their effect on
the plant’s ability to transition from a heterotrophic to an autotrophic condition during acclimatization was investigated.
Annona glabra L. shoots were cultured on woody plant medium supplemented with sucrose and different cytokinins to evaluate leaf tissue
for chloroplast development, chloroplast numbers, photosynthetic pigmentation, total photosynthetic potential, and soluble
sugar content. Plants were transferred to the rooting medium in the presence or absence of sucrose and then acclimatized.
Kinetin and benzyladenine (BAP) stimulated chloroplast differentiation. Inclusion of zeatin in the medium induced the formation
of greater numbers of chloroplasts in the leaves, while plants cultivated in the presence of only kinetin and BAP demonstrated
greater chlorophyll a and carotenoid content. The use of kinetin and BAP during in vitro culture promoted accumulation of dry matter during the acclimatization phase, especially in plants rooted under autotrophic
conditions (without sucrose). Kinetin and BAP promoted development of more leaf area and greater plant survival rates in plant
acclimatization on both autotrophic and heterotrophic media. The inhibitory effects of thidiazuron on the differentiation
of chloroplasts, accumulation of chlorophyll a, and photosynthetic potential were examined. 相似文献
2.
3.
Growth characteristics of the cyanobacterium Nostoc flagelliforme in photoautotrophic, mixotrophic and heterotrophic cultivation 总被引:1,自引:0,他引:1
Nostoc flagelliforme is a terrestrial cyanobacterium with high economic value. Dissociated cells separated from a natural colony of N. flagelliforme were cultivated for 7 days under either phototrophic, mixotrophic or heterotrophic culture conditions. The highest biomass,
1.67 g L−1 cell concentration, was obtained under mixotrophic culture, representing 4.98 and 2.28 times the biomass obtained in phototrophic
and heterotrophic cultures, respectively. The biomass in mixotrophic culture was not the sum as that in photoautotrophic and
heterotrophic cultures. During the first 4 days of culture, the cell concentration in mixotrophic culture was lower than the
sum of those in photoautotrophic and heterotrophic cultures. However, from the 5th day, the cell concentration in mixotrophic
culture surpassed the sum of those obtained from the other two trophic modes. Although the inhibitor of photosynthetic electron
transport DCMU [3-(3,4-dichlorophenyl)-1,1-dimethylurea] efficiently inhibited autotrophic growth of N. flagelliforme cells, under mixotrophic culture they could grow by using glucose. The addition of glucose changed the response of N.flagelliforme cells to light. The maximal photosynthetic rate, dark respiration rate and light compensation point in mixotrophic culture
were higher than those in photoautotrophic cultures. These results suggest that photoautotrophic (photosynthesis) and heterotrophic
(oxidative metabolism of glucose) growth interact in mixotrophic growth of N. flagelliforme cells. 相似文献
4.
In a coastal lagoon of Dravuni Island, Fiji, at least six species of compound ascidians, some of them harboringProchloron as symbiotic algae, were found in aSyringodium-dominated seagrass meadow. Based on their heterotrophic (filrer feeding rates) and autotrophic (photosynthetic) activities,
carbon gain of the ascidians was categorized into two groups: (i) supported by heterotrophic metabolism; and (ii) supported
by both heterotrophic and autotrophic metabolisms.Didemnum molle, Lissoclinum bistratum andLissolinum voeltzkowi belong to the latter group, and the relative contribution of the autotrophic process was a significant portion of their carbon
gain (52–74%). These symbiotic ascidians were found in light microhabitats, while the heterotrophic species occupied shady
environments rich in suspended organic materials, such as the sheath surface of the seagrass. 相似文献
5.
Summary
In vitro plantlets of Phalaenopsis ‘Happy Valentine’, Neofinetia falcate Hu, Cymbidium kanran Makino, and Cymbidium goeringii Reichb. f. were grown under photoautotrophic [high photosynthetic photon flux (PPF), high CO2 concentration, and increased number of air exchanges] and heterotrophic (low PPF, low CO2 concentration, no air exchanges) culture conditions. After 40 d of culture, a significant difference in plantlet growth was
observed between the two cultures. Total fresh and dry mass were on average 1.5 times greater in photoautotrophic culture
than in heterotrophic culture. Higher net photosynthetic rates were also observed for Phalaenopsis in photoautotrophic culture. In photoautotrophic culture, little difference was observed in air temperature between the inside
and outside of the culture vessel, whereas in heterotrophic culture, air temperature inside the culture vessel was 1–2°C higher
than that outside the culture vessel. Relative humidity inside the culture vessel was remarkably different between the two
cultures: 83–85% in photoautotrophic culture and 97–99% in heterotrophic culture. These results indicated that growth and
net photosynthetic rate of in vitro orchid plantlets were susceptible to the culture environments such as PPF, CO2 concentration, relative humidity (RH), and the number of air exchanges, which would allow a more efficient micropropagation
system for these orchid plants. 相似文献
6.
Experiments employing electron transport inhibitors, room- and low-temperature spectroscopy, and photochemical action spectra have led to a model for the respiratory chain of Pseudomonas carboxydovorans. The chain is branched at the level of b-type cytochromes or ubiquinone. One branch (heterotrophic branch) contained cytochromes b558, c, and a1; the second branch (autotrophic branch) allowed growth in the presence of CO and contained cytochromes b561 and o (b563). Electrons from the oxidation of organic substrates were predominantly channelled into the heterotrophic branch, whereas electrons derived from the oxidation of CO or H2 could use both branches. Tetramethyl-p-phenylenediamine was oxidized via cytochromes c and a exclusively. The heterotrophic branch was sensitive to antimycin A, CO, and micromolar concentrations of cyanide. The autotrophic branch was sensitive to 2-n-heptyl-4-hydroxyquinoline-N-oxide, insensitive to CO, and inhibited only by millimolar concentrations of cyanide. The functioning of cytochrome a1 as a terminal oxidase was established by photochemical action spectra. Reoxidation experiments established the functioning of cytochrome o as an alternative CO-insensitive terminal oxidase of the autotrophic branch. 相似文献
7.
The metabolic theory of ecology predicts that temperature affects heterotrophic processes more strongly than autotrophic processes. We hypothesized that this differential temperature response may shift mixotrophic organisms towards more heterotrophic nutrition with rising temperature. The hypothesis was tested in experiments with the mixotrophic chrysophyte Ochromonas sp., grown under autotrophic, mixotrophic and heterotrophic conditions. Our results show that (1) grazing rates on bacterial prey increased more strongly with temperature than photosynthetic electron transport rates, (2) heterotrophic growth rates increased exponentially with temperature over the entire range from 13 to 33 °C, while autotrophic growth rates reached a maximum at intermediate temperatures and (3) chlorophyll contents during mixotrophic growth decreased at high temperature. Hence, the contribution of photosynthesis to mixotrophic growth strongly decreased with temperature. These findings support the hypothesis that mixotrophs become more heterotrophic with rising temperature, which alters their functional role in food webs and the carbon cycle. 相似文献
8.
The effects of photosynthetic photon flux density (PPFD) on antioxidant metabolism and photosynthetic properties in leaves
during ex vitro establishment of micropropagated Rauvolfia tetraphylla plantlets were investigated. In vitro-propagated plantlets were acclimatized at either 50 (Low-light = LL) or 300 (High-light = HL)
μmol m−2s−1 photosynthetic PPFD for 4 weeks under controlled conditions. Increases in chlorophyll (Chl) a, b and carotenoid levels were observed in plantlets acclimatized at both light intensities. At transplantation, micropropagated
plantlets were not photosynthetically active, but the net photosynthetic rate increased in newly formed leaves over time during
acclimatization. The observed differences in pigment contents and photosynthetic rates suggested adaptation of plantlets from
heterotrophic to autotrophic mode of nutrition during acclimatization. Changes in activities of antioxidant enzymes were also
observed during acclimatization. Superoxide dismutase activity increased in plantlets acclimatized at HL intensities. Likewise,
changes in activity of catalase and ascorbate peroxidase were also detected. These observed changes reflected the ability
of plants in developing an antioxidant enzymatic defense system aiding in survival against oxidative stress and in reducing
release of free radicals. 相似文献
9.
Relative growth rate, isocitrate lyase activity, chlorophyll, protein, lipid, and soluble carbohydrate contents were investigated in Chlamydomonas humicola Lucksch during auto-, mixo-, and heterotrnphic growth. Mixotrophic cells have a relative growth rate of 1.66 d –1as compared to 0.78 d –1 and 0.21 d –1 for hetero- and autotrophic cells, respectively. Addition of acetate to autotrophic cells resulted in an increase in cell dry weight during the first day, followed by a rapid decrease and stabilization at 40 pg·cell –1. Cellular yield of mixotrophu cells, on a dry weight basis, was 6.6 times that of heterotrophic cells and 21.9 limes that of autotrophic ones. After 4 d, mixotrophic cells were characterized by higher chlorophyll (3.6% dry weight [d.w.]) and protein (58.6% d.w.) contents and lower lipid (4.8% d.w.) and soluble carbohydrate (1.3% d.w.) contents than those of autotrophic (2.6% d.w. chlorophyll, 31.0% d.w. protein, 10.2% d.w. lipid, and 6.5% d.w. soluble carbohydrate) and heterotrophic (1.5% d.w. chlorophyll, 36.9% d.w. protein, 5.6% d.w. lipid, and 6.0% d.w. soluble carbohydrate) cells. The ratio of chlorophyll a/b was highest in heterotrophic cells due to lower chlorophyll b content. Isocitrate lyase activity, a key enzyme in ecetate assimitation, could not be detected in autotrophic cells. Addition of 10 mM acetate to the culture medium of hetero- and mixotrophic cells resulted in increased isocitrate lyase activity with a maximum after 24 h, followed by a decline in activity over a 7-d period. After 7 d of growth, only 0.01 mM acetate was found in the culture medium of mixotrophic cells as compared to 3.2 mM in the medium of heterotrophic ones, from an initial concentration of 10 mM. 相似文献
10.
Summary. Cell proliferation of dinoflagellates is negatively affected by mechanical agitation and red tides caused by members of the
group have been correlated with periods of calm sea conditions. The mechanism involved in the mechanically transduced inhibition
of cell proliferation is thought to involve the disruption of the cell division apparatus. In this study, we used highly synchronized
cells and flow cytometry to study the effects of mechanical agitation on cell cycle progression. We observed that mechanical
agitation induced transient cell cycle arrest at G1 phase, in both the heterotrophic dinoflagellate Crypthecodinium cohnii and the photosynthetic dinoflagellate Heteroscapsa triquetra.
Received March 12, 2002; accepted July 20, 2002; published online November 29, 2002 相似文献
11.
M. E. Wilson 《Polar Biology》1990,10(5):337-341
Summary Photosynthetic capacity, chlorophyll content and leaf and cell morphology were compared in Grimmia antarctici from wet and dry sites in the Bailey Peninsula SSSI, near Casey Station, East Antarctica. In wet sites G. antarctici grew as a turf with tall shoots of loosely packed long leaves: in very dry sites it formed small cushions with short shoots of small tightly packed leaves. Intermediate forms (large cushions) were also frequently observed in less extreme situations. Cell size and number were greater in drier sites. The chlorophyll content, chlorophyll a/b ratio and the light saturated photosynthetic and dark respiration rates at full turgor and under enhanced conditions of CO2 were the same. This rules out a direct effect of water stress on the integrity of the photosynthetic apparatus and implies that the cushion form is a product of direct effects of water availability on cell division and differentiation and CO2 assimilation under field conditions. 相似文献
12.
M. I. H. Aleem 《Current microbiology》1980,4(6):331-336
Cell-free preparations fromParacoccus denitrificans grown aerobically under autotrophic and heterotrophic conditions catalyzed succinate- and ascorbate-linked ATP-dependent
NAD+ reduction. The succinate-linked NAD+ reduction was sensitive to rotenone and indicated the participation of coupling site 1. The ascorbate-linked, energy-driven,
reversed electron flow was sensitive to antimycin A or 2-n-heptyl-4-hydroxyquinoline-N-oxide and rotenone, thus indicating the mediation of coupling sites 2 and 1. The aerobic oxidation of three ascorbate equivalents
was required to reduce one NAD+ equivalent in the autotrophic system, while no NAD+ reduction coupled to ascorbate oxidation occurred in the heterotrophic system unlessN,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) was present. In the later case, the oxidation of 24 equivalents of reduced TMPD was required to support
the reduction of each equivalent of NAD+ These results indicated that, while there was an efficient energy-coupling at site 3 in the autotrophic system, the heterotrophic
system appeared to posses a very weak or inefficient terminal energy-coupling site. 相似文献
13.
In 2007, a novel, putatively photosynthetic picoeukaryotic lineage, the ‘picobiliphytes’, with no known close eukaryotic relatives, was reported from 18S environmental clone library sequences and fluorescence in situ hybridization. Although single cell genomics later showed these organisms to be heterotrophic rather than photosynthetic, until now this apparently widespread group of pico-(or nano-)eukaryotes has remained uncultured and the organisms could not be formally recognized. Here, we describe Picomonas judraskeda gen. et sp. nov., from marine coastal surface waters, which has a ‘picobiliphyte’ 18S rDNA signature. Using vital mitochondrial staining and cell sorting by flow cytometry, a single cell-derived culture was established. The cells are biflagellate, 2.5–3.8×2–2.5 µm in size, lack plastids and display a novel stereotypic cycle of cell motility (described as the “jump, drag, and skedaddle”-cycle). They consist of two hemispherical parts separated by a deep cleft, an anterior part that contains all major cell organelles including the flagellar apparatus, and a posterior part housing vacuoles/vesicles and the feeding apparatus, both parts separated by a large vacuolar cisterna. From serial section analyses of cells, fixed at putative stages of the feeding cycle, it is concluded that cells are not bacterivorous, but feed on small marine colloids of less than 150 nm diameter by fluid-phase, bulk flow endocytosis. Based on the novel features of cell motility, ultrastructure and feeding, and their isolated phylogenetic position, we establish a new phylum, Picozoa, for Picomonas judraskeda, representing an apparently widespread and ecologically important group of heterotrophic picoeukaryotes, formerly known as ‘picobiliphytes’. 相似文献
14.
Octavio Perez‐Garcia Luz E. De‐Bashan Juan‐Pablo Hernandez Yoav Bashan 《Journal of phycology》2010,46(4):800-812
Heterotrophic growth of microalgae presents significant economic advantages over the more common autotrophic cultivation. The efficiency of growth and nitrogen, phosphorus, and glucose uptake from synthetic wastewater was compared under heterotrophic, autotrophic, and mixotrophic regimes of Chlorella vulgaris Beij. immobilized in alginate beads, either alone or with the bacterium Azospirillum brasilense. Heterotrophic cultivation of C. vulgaris growing alone was superior to autotrophic cultivation. The added bacteria enhanced growth only under autotrophic and mixotrophic cultivations. Uptake of ammonium by the culture, yield of cells per ammonium unit, and total volumetric productivity of the culture were the highest under heterotrophic conditions when the microalga grew without the bacterium. Uptake of phosphate was higher under autotrophic conditions and similar under the other two regimes. Positive influence of the addition of A. brasilense was found only when light was supplied (autotrophic and mixotrophic), where affinity to phosphate and yield per phosphate unit were the highest under heterotrophic conditions. The pH of the culture was significantly reduced in all regimes where glucose was consumed, similarly in heterotrophic and mixotrophic cultures. It was concluded that the heterotrophic regime, using glucose, is superior to autotrophic and mixotrophic regimes for the uptake of ammonium and phosphate. Addition of A. brasilense positively affects the nutrient uptake only in the two regimes supplied with light. 相似文献
15.
α-Tocopherol is the most biologically active component of vitamin E and is synthesized only by photosynthetic organisms. Two
heterotrophic cell lines of sunflower (Helianthus annuus L.) of differing α-tocopherol biosynthetic capability, three-fold higher in the high synthesizing cell line, HT, than in
the low synthesizing one, LT, were previously identified. To investigate the relationship between α-tocopherol biosynthesis
and photomixotrophic culture conditions, a new photomixotrophic sunflower cell line HS3 was established by selecting HT cells
able to grow in the presence of a ten-fold reduced sucrose concentration in the culture medium. The photosynthetic properties
of HS3 cells were characterized in comparison with HT and LT cells, revealing an increase in chlorophyll content, chloroplast
number, and level of the photosynthesis related enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Furthermore,
an enhanced expression of the gene encoding for the tocopherol biosynthetic enzyme geranyl-geranylpyrophosphate synthase (GGPPS)
was observed in HS3 cells. HS3 cells also revealed a 25% and a more than three-fold higher tocopherol level than HT and LT,
respectively, indicating a positive correlation between α-tocopherol biosynthesis of sunflower cell cultures and their photosynthetic
properties. These findings can be useful for improving the tocopherol yields of the sunflower in vitro production system. 相似文献
16.
Effects of UVB radiation on freshwater autotrophic and heterotrophic picoplankton in a subalpine lake 总被引:1,自引:0,他引:1
The effects of UVB radiation on the activity of heterotrophic (HPP) and
autotrophic (APP) picoplankton (0.2-2 m) and
of autotrophic assemblages >2 m has been measured and
compared. Under natural UVB irradiance in a large, deep, oligotrophic
subalpine lake (Lago Maggiore, 4555N) with mean dissolved organic carbon
(DOC) concentrations of 1 mg Cl-1, the
microorganisms of the two size fractions were not significantly
photoinhibited in their autotrophic and heterotrophic activities. The
vertical attenuation coefficient (Kd) for irradiance
at 305 nm ranged from 1.45 to 1.67 during spring and summer. The mixing
layer extended to a greater depth than the layer affected by UVB radiation
(z1% < zmix), thus
enabling the microorganisms living there to photoadapt. As the assimilation
numbers of APP and nanoplankton were higher at 2 m depth than near the
surface, we suspected that the influence of longer wavelength (UVA,
photosynthetically active radiation) could be stronger than UVB in
affecting the photosynthetic efficiency of natural populations. The
artificial increase in UVB irradiance had a higher detrimental effect on
HPP due to their smaller size, less protection and indirect effects through
autotrophic cell inhibition. Picocyanobacteria were percentually more
affected by UVB than nanoplankton during April due to the presence of
diatoms, which are more resistant than other algal groups to solar UVB
irradiance. Furthermore, picocyanobacteria had lower assimilation numbers
with respect to larger phytoplankton in the quartz tubes during
stratification.
相似文献
17.
Greening and growth of suspension-cultured cells of Chenopodium rubrum under conditions of heterotrophic and autotrophic nutrition 总被引:2,自引:2,他引:0
Abstract Dark-grown cell suspension cultures of Chenopodium rubrum lacking chlorophyll greened strongly upon transfer to illumination and fresh medium. This greening took place both in the presence of sucrose as a carbon source and in a mineral salt medium under an atmosphere enriched in CO2. The synthesis of chlorophyll was in each case closely accompanied by the development of high levels of enzymes typical of photosynthesis. Greening in sugar-containing medium resulted in a rapid acquisition of characteristic features of photomixotrophic cultures, which have the ability to survive for a prolonged period in a minimal photoautotrophic environment in the light long after the initially present sucrose has been depleted from the medium. Greening under autotrophic conditions represented a direct transition from starvation conditions resulting from prolonged heterotrophic batch growth to successful photoautotrophy. Thus, light triggered the build-up of a competent photosynthetic apparatus irrespective of the nutritional necessity for autotrophy. Illumination and greening did not influence catabolic enzyme activities beyond that increase of metabolic activity which is required for the production of photosynthetic machinery. 相似文献
18.
Adolf Jason E.; Stoecker Diane K.; Harding Lawrence W. Jr 《Journal of plankton research》2006,28(8):737-751
We studied autotrophic and heterotrophic C metabolism duringmixotrophic growth of Karlodinium micrum (Leadbeter et Dodge)Larsen (Dinophyceae) on prey Storeatula major (Cryptophyceae).Our goal was to determine the balance of autotrophy and heterotrophythat supports mixotrophic growth in K. micrum. Assimilationof inorganic 14C and 14C-labeled prey was used to separate thequantity and quality (i.e., lipid, polysaccharide and protein)of C obtained by autotrophy and heterotrophy, respectively.Growth rates (µ) of mixotrophic K. micrum were 0.520.75div.·day1, equal to or greater than the maximumautotrophic growth rate (0.55 div.·day1) of K.micrum. Autotrophy represented 2769% of gross C uptakeduring mixotrophic growth. Cellular photosynthetic performance(PPcell, pg C cell1·day1) was 2452%lower during mixotrophic growth than during autotrophic growthof K. micrum. Mixotrophic K. micrum assimilated 16% less photosynthateas protein compared to autotrophic K. micrum, while proteinwas the major net assimilation product (52%) from ingested preyC. Growth efficiency (%GE) of mixotrophic cultures, based onboth autotrophic and heterotrophic C sources, averaged 36 ±2.9%, slightly lower than the 4050% GE typical of purelyautotrophic K. micrum, but higher C gains associated with heterotrophicfeeding more than compensated for the decrease in %GE in mixotrophicK. micrum. We conclude that mixotrophic growth of K. micrumis dominated by heterotrophic metabolism, although photosynthesiscontinues at a lowered rate. This is consistent with a shifttoward secondary production in plankton assemblages dominatedby mixotrophically growing K. micrum. 相似文献
19.
The marine cryptophyte Pyrenomonas salina Santore is capable of autotrophic and heterotrophic nutrition. We studied the physiological and ultrastructural changes that accompany the shift between these nutritional modes. The addition of glycerol to batch cultures of P. salina, grown at an irradiance limiting for photoautotrophic growth, increased its growth rate and induced specific biochemical and structural changes in its photosynthetic system. Results from extracted pigment analyses, thin-section electron microscopy, and freeze-fracture electron microscopy indicated that glycerol addition reduced the cell phycoerythrin content, phycoerythrin to chlorophyll a ratio, degree of thylakoid packing, number of thylakoids · cell?1, and PSII particle size. These properties were reduced to a similar extent in cells grown photoautotrophically under an irradiance saturating for growth. These results are consistent with the hypothesis that enhancement of heterotrophic potential occurs at the expense of light-harvesting ability in glycerol-grown P. salina. 相似文献
20.
J. R. Cook 《Plant physiology》1966,41(5):821-825
Axenic populations of the photosynthetic protozoan Euglena gracilis, grown with autotrophic nutrition, were synchronized with respect to cell division by culture on an alternating light-dark cycle. No cell divisions occurred in the light periods; approximately 100% of the cells divided in the dark periods. In such cultures, the synthesis of photosynthetic pigments and accumulation of polysaccharide were confined to the light periods. The capacity for photosynthesis, however, increased continuously over the entire light-dark cycle, and is thus not directly correlated with pigment content. A correlation was seen between photosynthetic capacity and protein content, suggesting that enzymatic mechanisms of the photosynthetic apparatus might be the limiting factor. Estimates of total photosynthetic activity indicate that about 5 x 10(-6) calories are required for the synthesis of a new cell. 相似文献