共查询到20条相似文献,搜索用时 31 毫秒
1.
Yan Gong Hong-Nong Chou Chi-dao Tu Xi Liu Jiantong Liu Lirong Song 《Journal of applied phycology》2009,21(2):225-231
Arsenic pollution and eutrophication are both prominent issues in the aquaculture ponds of Taiwan. It is important to study
the effects of arsenic on algal growth and toxin production in order to assess the ecological risk of arsenic pollution, or
at least to understand naturally occurring ponds. The sensitivity of algae to arsenate has often been linked to the structural
similarities between arsenate and phosphate. Thus, in this study we examined the effects of arsenate (10−8 to 10−4 M) on Microcystis aeruginosa TY-1 isolated from Taiwan, under two phosphate regimes. The present study showed that M. aeruginosa TY-1 was arsenate tolerant up to 10−4 M, and that this tolerance was not affected by extracellular phosphate. However, it seems that extracellular phosphate contributed
to microcystin production and leakage by M. aeruginosa in response to arsenate. Under normal phosphate conditions, total toxin yields after arsenate treatment followed a typical
inverted U-shape hormesis, with a peak value of 2.25 ± 0.06 mg L−1 in the presence of 10−7 M arsenate, whereas 10−8 to 10−6 M arsenate increased leakage of ∼75% microcystin. Under phosphate starvation, total toxin yields were not affected by arsenate,
while 10−6 and 10−5 M arsenate stimulated microcystin leakage. It is suggested that arsenate may play a role in the process of microcystin biosynthesis
and excretion. Given the arsenic concentrations in aquaculture ponds in Taiwan, arsenate favors survival of toxic M. aeruginosa in such ponds, and arsenate-stimulated microcystin production and leakage may have an impact on the food chain. 相似文献
2.
As a common pollutant, nitrite concentrations can approach 15 mg NO2−-N L−1 in some aquatic systems. Microcystis aeruginosa blooms are common and widespread in eutrophic freshwater bodies. In this study, M. aeruginosa was exposed to nitrite concentrations ranging from 0 to 15 mg NO2−-N L−1, and the responses of M. aeruginosa were investigated. The specific growth rates, maximum cell densities, light-saturated photosynthetic rates (Pm
chla
), dark respiration rates (Rd
chla
), and apparent photosynthetic efficiencies (αchla
) showed a significant decline with nitrite concentrations increasing. Electrical conductivity and malondialdehyde contents
investigation revealed cell membrane damage and apparent leakage of intracellular contents under high nitrite level conditions
due to oxidative stress enhancement. Intracellular microcystin (MC)-LR content reached the highest value at 10 mg NO2−-N L−1; however, extracellular MC-LR contents showed a continuous increase until 15 mg NO2−-N L−1 owing to the increasing leakage of intracellular contents. These results elucidated that the high-level nitrite inhibited
M. aeruginosa growth by rising oxidative stress, damaging cell membrane, and reducing photosynthesis. However, the moderate increase in
nitrite concentrations promoted toxin production and release of toxin. 相似文献
3.
Briand JF Jacquet S Flinois C Avois-Jacquet C Maisonnette C Leberre B Humbert JF 《Microbial ecology》2005,50(3):418-428
Between 1999 and 2002, a routine survey of water quality in the Lac du Bourget was performed to study the dynamics and microcystin
(MC) production of Planktothrix rubescens. Using liquid chromatography coupled to diode array detection and mass spectrometry, we found that two main variants ([d-Asp3] and [d-Asp3, Dhb7] microcystin-RR) were produced. The proportion of these two variants was not influenced by the depth or season of sampling.
Expressed in microcystin-LR equivalents, high microcystin concentrations were recorded from August to December each year,
reaching values of up to 6.7 μg L−1. A significant correlation was found between the microcystin cell content and the cell densities of P. rubescens. Cellular quotas of microcystins ranged from 0.1 to 0.3 pg cell−1. Simultaneously, laboratory experiments were performed on a strain of P. rubescens isolated from the lake to assess the potential impact of various P–PO43− concentrations on intra- and extracellular microcystin production. Unlike natural populations, this strain only produced
[d-Asp3] MC-RR. The intracellular microcystin content was similarly correlated to the cell density, but the cellular quota was slightly
higher (0.3–0.7 pg cell−1) than in the natural population. Again, as in the natural population, a linear relationship was found between growth rate
and microcystin production rate. These findings support the hypothesis that environmental factors, such as phosphate concentrations,
have no direct impact on microcystin production by P. rubescens, but act indirectly by affecting growth rate. 相似文献
4.
C. S. Jeong H. N. Murthy E. J. Hahn H. L. Lee K. Y. Paek 《Acta Physiologiae Plantarum》2009,31(1):219-222
The effect of the root-inoculum size and axuin concentration on growth of adventitious roots and accumulation of ginsenosides
were studied during suspension cultures of ginseng (Panax ginseng C.A. Meyer). Of the various concentrations of indole-3-butyric acid (IBA) and γ-naphthaleneacetic acid (NAA) used as supplementary
growth regulators along with Murashige and Skoog medium, 25 μM IBA was found suitable for lateral root induction and growth,
as well as accumulation of ginsenosides. Inoculum size of 5 g L−1 was found suitable for optimal biomass (10.5 g L−1 dry biomass) and ginsenosides (5.4 mg g−1 DW) accumulation. Of the various length of root inocula tested (chopped to 1–3, 4–6, 7–10 mm and un-chopped), root inocula
of 7–10 mm was found suitable for biomass and ginsenoside accumulation. 相似文献
5.
Smita Srivastava Ashok Kumar Srivastava 《In vitro cellular & developmental biology. Plant》2012,48(1):73-84
Azadirachtin, a well-known biopesticide, is a secondary metabolite extracted from the seeds of Azadirachta indica. In the present study, azadirachtin was produced in hairy roots of A. indica, generated by Agrobacterium rhizogenes-mediated transformation of leaf explants. Liquid cultures of A. indica hairy roots were developed with a liquid-to-flask volume ratio of 0.15. The kinetics of growth and azadirachtin production
were established in a basal plant growth medium containing MS medium major and minor salts, Gamborg’s medium vitamins, and
30 g l−1 sucrose. The highest azadirachtin accumulation in the hairy roots (up to 3.3 mg g−1) and azadirachtin production (∼44 mg l−1) was obtained on Day 25 of the growth cycle, with a biomass production of 13.3 g l−1 dry weight. To enhance the production of azadirachtin, a Plackett–Burman experimental design protocol was used to identify
key medium nutrients and concentrations to support high root biomass production and azadirachtin accumulation in hairy roots.
The optimal nutrients and concentrations were as follows: 40 g l−1 sucrose, 0.19 g l−1 potassium dihydrogen phosphate, 3.1 g l−1 potassium nitrate, and 0.41 g l−1 magnesium sulfate. Concentrations were determined by a central composite design protocol and verified in shake-flask cultivation.
The optimized medium composition yielded a root biomass production of 14.2 g l−1 and azadirachtin accumulation of 5.2 mg g−1, which was equivalent to an overall azadirachtin production of 73.84 mg l−1, 68% more than that obtained under non-optimized conditions. 相似文献
6.
Xue-Song Shen Qi Su Zhuang-ping Qiu Jing-yi Xu Yan-xia Xie Han-fu Liu Yi Liu 《Biological trace element research》2010,136(1):117-125
The toxic effects of artesunate and dihydroartemisinin on the growth metabolism of Tetrahymena thermophila BF5 were studied by microcalorimetry. The results showed that: (1) low concentrations of artesunate (≤1 mg L−1) and dihydroartemisinin (≤ 2 mg L−1) promoted the growth metabolism of T. thermophila BF5, whereas high concentrations of artesunate (1–60 mg L−1) and dihydroartemisinin (2–60 mg L−1) inhibited its growth; (2) the half inhibition concentrations IC50 of artesunate and dihydroartemisinin were 17.5817 and 9.5089 mg L−1, respectively. It was concluded that the inhibition of dihydroartemisinin was stronger than that of artesunate. 相似文献
7.
Durmaz-Sam S Sayar NA Topal-Sarikaya A Sayar AA 《Bioprocess and biosystems engineering》2011,34(8):997-1005
The potential of the dried yeast, wild-type Schizosaccharomyces pombe, to remove Ni(II) ion was investigated in batch mode under varying experimental conditions including pH, temperature, initial
metal ion concentration and biosorbent dose. Optimum pH for biosorption was determined as 5.0. The highest equilibrium uptake
of Ni(II) on S. pombe, q
e, was obtained at 25 °C as 33.8 mg g−1. It decreased with increasing temperature within a range of 25–50 °C denoting an exothermic behaviour. Increasing initial
Ni(II) concentration up to 400 mg L−1 also elevated equilibrium uptake. No more adsorption took place beyond 400 mg L−1. Equilibrium data fitted better to Langmuir model rather than Freundlich model. Sips, Redlich–Peterson, and Kahn isotherm
equations modelled the investigated system with a performance not better than Langmuir. Kinetic model evaluations showed that
Ni(II) biosorption process followed the pseudo-second order rate model while rate constants decreased with increasing temperature.
Gibbs free energy changes (ΔG°) of the system at 25, 30, 35 and 50 °C were found as −1.47E + 4, −1.49E + 4, −1.51E + 4, and −1.58E + 4 J mol−1, respectively. Enthalpy change (ΔH°) was determined as −2.57E + 3 J mol−1 which also supports the observed exothermic behaviour of the biosorption process. Entropy change (ΔS°) had a positive value (40.75 J mol−1 K−1) indicating an increase in randomness during biosorption process. Consequently, S. pombe was found to be a potential low-cost agent for Ni(II) in slightly acidic aqueous medium. In parallel, it has been assumed
to act as a separating agent for Ni(II) recovery from its aqueous solution. 相似文献
8.
Variation of Microcystin Content of Cyanobacterial Blooms and Isolated Strains in Lake Grand-Lieu (France) 总被引:9,自引:0,他引:9
C. Vezie L. Brient K. Sivonen G. Bertru J.-C. Lefeuvre M. Salkinoja-Salonen 《Microbial ecology》1998,35(2):126-135
Abstract
Cyanobacterial blooms were sampled at five locations in Lake Grand-Lieu on seven different occasions during May–October 1994.
Strains of Microcystis aeruginosa and Anabaena circinalis were isolated from the samples. Microcystins were detected in freeze-dried field samples and the isolated strains by HPLC.
The toxins were present in the blooms sampled between June and October. The microcystin content in the blooms varied with
site and time, from undetectable concentrations to 0.23 mg g−1. The highest concentrations of microcystin were found in blooms sampled in September. Microcystin-LR and microcystins with
retention times close to the retention time of [Dha7]microcystin-RR (probably varieties of microcystin-RR) were found in the field samples. Sixteen of the 98 isolated M. aeruginosa strains and 2 of the 24 A. circinalis strains produced microcystins. The total amount of microcystins varied from undetectable concentrations to 5.06 mg g−1 in the M. aeruginosa isolates, and from undetectable concentrations to 1.86 mg g−1 in the A. circinalis strains. Microcystin-LR was the main toxin found in strains of M. aeruginosa, but was not present in strains of A. circinalis. Both microcystin-producing strains and strains that did not produce microcystin coexisted in the bloom samples.
Received: 23 January 1997; Accepted: 25 March 1997 相似文献
9.
Abhinav Grover Jayashankar S. Yadav Ranjita Biswas Choppakatla S. S. Pavan Punita Mishra Virendra S. Bisaria Durai Sundar 《Plant Cell, Tissue and Organ Culture》2012,108(2):323-331
Cell suspension cultures of Camellia sinensis were established in 250 ml shake flasks. Flasks contained 50 ml liquid medium of either Murashige and Skoog (MS), N/5 MS
or Heller medium containing different levels of 6-benzyladenine (BA) (0.05–2 mg l−1), 2,4-dichlorophenoxyacetic acid (2,4-D) (1–10 mg l−1), and sucrose (10–50 g l−1). Moreover, the pH of the medium was varied from 5.2–6.2. In addition, cultures were subjected to light irradiation as well
as to complete darkness. Following optimization of aroma and terpenoid extraction methods, cell cultures were analyzed for
the volatile compounds using GC/MS. A total of 43 compounds were identified using the micro SDE apparatus. Among the major
monoterpenoids obtained were α-terpineol and nerol. Moreover, other high aroma-value compounds, including 2-ethyl hexanol,
benzyl alcohol, benzene acetaldehyde, nonanal and phenylethylalcohol were also detected. The highest levels of these compounds
were obtained from cell suspension cultures grown in MS medium containing 5 mg l−1 2,4-D, 1 mg l−1 BA and 30 g l−1 sucrose at pH of 5.8 with incubation in complete darkness. 相似文献
10.
Filtrates from crushed Moringa oleifera seeds were tested for their effects on growth and Photosystem II efficiency of the common bloom-forming cyanobacterium Microcystis aeruginosa. M. aeruginosa populations exhibited good growth in controls and treatments with 4- and 8-mg crushed Moringa seeds per liter, having similar growth rates of 0.50 (±0.01) per day. In exposures of 20- to 160-mg crushed Moringa seeds L−1, growth rates were negative and on average −0.23 (±0.05) .day−1. Presumably, in the higher doses of 20- to 160-mg crushed seeds per liter, the cyanobacteria died, which was supported by
a rapid drop in the Photosystem II efficiency (ΦPSII), while the ΦPSII was high and unaffected in 0, 4, and 8 mg L−1. High-density populations of M. aeruginosa (chlorophyll-a concentrations of ∼270 μg L−1) were reduced to very low levels within 2 weeks of exposure to ≥80-mg crushed seeds per liter. At the highest dosage of 160 mg L−1, the ΦPSII dropped to zero rapidly and remained nil during the course of the experiment (14 days). Hence, under laboratory conditions,
a complete wipeout of the bloom could be achieved. This is the first study that yielded evidence for cyanobactericidal activity
of filtrate from crushed Moringa seeds, suggesting that Moringa seed extracts might have a potential as an effect-oriented measure lessening cyanobacterial nuisance. 相似文献
11.
Decolorization of Acid red 151 by Aspergillus niger SA1 under different physicochemical conditions 总被引:1,自引:0,他引:1
Naeem Ali Ikramullah Ghosia Lutfullah Abdul Hameed Safia Ahmed 《World journal of microbiology & biotechnology》2008,24(7):1099-1105
The fungal strain A. niger SA1 isolated from textile wastewater pond proved to be an important source of remediation (decolorization/degradation) for
textile dye, AR 151 (Reactive diazo dye) under different physicochemical conditions. Decolorization assays of AR 151 were
carried out in Simulated textile effluent under shake flask condition for 8 days. Decolorization (at 20 mg l−1 of dye) and related biomass production overall decreased with increase in pH from 5 to 9, at 30°C. It was maximum (95.71%)
at pH 5 with highest amount of three residual products (36.91 (α-naphthol = 5.72) (sulfanilic acid = 24.81) (aniline = 6.38))
besides 2.05 mg ml−1 of biomass production at an optimum concentration 6 and 0.1 mg l−1 of glucose and urea respectively. The formation of the three products followed a quite different pattern at different pH
values, however, it was considerably low (Total = 2.81 mg l−1) compared to the amount of decolorization (67.26%) at pH 8. Decolorization (95–97%) was most favored under mesophilic temperature
(25–45°C). It increased i.e., 90–98% with subsequent increase in dye from 10 to 100 mg l−1, kept ≥50% below 400 mg l−1 and drastically declined to 17% at 500 mg l−1 of dye. Apparently, decolorization is found to be associated with fungal growth and hyphal uptake mechanism (Biosorption/Bioadsorption),
however, mineralization of AR 151 and related products under different operational conditions also suggested a metabolically
mediated decolorization/degradation. 相似文献
12.
Synergistic effect of morphactin on cytokinin-induced production of isoflavonoids in cell cultures of Pueraria tuberosa (Roxb. ex. Willd.) DC 总被引:1,自引:0,他引:1
Isoflavonoids, the functional molecules of Fabaceae, are under clinical trials against cancer, osteoporosis and cardiovascular
diseases. In this study, the efficacy of different plant growth regulators was evaluated for optimizing the production of
isoflavonoids in Pueraria tuberosa. The cultures were maintained in Murashige and Skoog’s medium containing 0.1 mg l−1 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 0.1 mg l−1 kinetin. The addition of 5.0 mg l−1 N6-(2-Isopentenyl) adenine (2iP) resulted in about ∼32-folds increase in production of isoflavonoids, while about ∼23-folds
increase was recorded in the absence of kinetin in the maintenance medium. A maximum yield of isoflavonoids (∼80 mg l−1; 82-folds increase) was obtained in cultures grown at 0.1 mg l−1 morphactin and 5.0 mg l−1 of 2iP. However, 2,4,5-T in combination with 2iP was ineffective for their production. Among different plant growth regulators
tested, maximum yields of puerarin, genistin, daidzein and genistein were 17.4, 15.9, 69.0 and 0.04 mg l−1, respectively. The study suggested that the presence of two cytokinins or 2iP with morphactin in the culture medium markedly
enhanced the production of isoflavonoids in P. tuberosa. 相似文献
13.
Qi Xiang Zhang Yu Sun Heng Kang Hu Bei Chen Chun Tao Hong Hai Peng Guo Yin Hui Pan Bing Song Zheng 《In vitro cellular & developmental biology. Plant》2012,48(1):50-57
Miscanthus sinensis (Poaceae) is a typical perennial giant grass of East Asia. Due to its high photosynthetic efficiency, low input requirements,
and high biomass production, M. sinensis shows outstanding potential as a biofuel feedstock. However, the lack of an efficient tissue culture system may limit its
utilization potential. Different explants of M. sinensis were evaluated to develop an efficient tissue culture system. Shoot apices from in vitro-germinated seedling explants were tested for adventitious bud proliferation. The highest level of proliferation (multiplication
coefficient 6.69) was obtained when shoot apices were cultured on Murashige and Skoog (MS) medium supplemented with 1.0 mg L−1 6-benzyladenine (BA), 2.0 mg L−1 kinetin, 0.05 mg L−1 α-naphthalene acetic acid (NAA), 3% sucrose, and 0.8% agar. The highest rooting percentage (95.4%) was obtained when adventitious
buds were cultured on half-strength MS medium supplemented with 0.2 mg L−1 NAA, 3% sucrose, and 0.8% agar. Significant differences were found in the formation of embryogenic callus among different
explant types. The embryogenic callus derived from epicotyls had the highest regeneration capacity when cultured on a medium
supplemented with 2.0 mg L−1 2,4-dichlorophenoxyacetic acid, 0.5 mg L−1 BA, and 0.1 mg L−1 thiamine. Under these conditions, the callus induction percentage was 82%. 相似文献
14.
Michael Pescheck Marco Antonio Mirata Bianca Brauer Ulrich Krings Ralf Günter Berger Jens Schrader 《Journal of industrial microbiology & biotechnology》2009,36(6):827-836
A closed gas loop bioprocess was developed to improve fungal biotransformation of monoterpenes. By circulating monoterpene-saturated
process gas, the evaporative loss of the volatile precursor from the medium during the biotransformation was avoided. Penicillium solitum, isolated from kiwi, turned out to be highly tolerant towards monoterpenes and to convert α-pinene to a range of products
including verbenone, a valuable aroma compound. The gas loop was mandatory to reproduce the production of 35 mg L−1 verbenone obtained in shake flasks and also in the bioreactor. Penicillium digitatum DSM 62840 regioselectively converted (+)-limonene to the aroma compound α-terpineol, but shake flask cultures revealed a
pronounced growth inhibition when initial concentrations exceeded 1.9 mM. In the bioreactor, toxic effects on P. digitatum during biotransformation were alleviated by starting a sequential feeding of non-toxic limonene portions after a preceding
growth phase. Closing the precursor-saturated gas loop during the biotransformation allowed for an additional replenishment
of limonene via the gas phase. The gas loop system led to a maximum α-terpineol concentration of 1,009 mg L−1 and an average productivity of 8–9 mg L−1 h−1 which represents a doubling of the respective values previously reported. Furthermore, a molar conversion yield of up to
63% was achieved.
M. Pescheck and M. A. Mirata have contributed equally to this work. 相似文献
15.
N. Selvaraj S. Kasthurirengan A. Vasudevan M. Manickavasagam C. W. Choi A. Ganapathi 《In vitro cellular & developmental biology. Plant》2010,46(4):329-337
Efficient Agrobacterium tumefaciens-mediated transformation and a higher recovery of transformed plants of cucumber cv. Poinsett76 were achieved via direct organogenesis
from cotyledon explants. Stable transformants were obtained by inoculating explants with A. tumefaciens strains EHA105 or LBA4404, both harboring the binary vector pME508, which contains the neomycin phosphotransferase II (nptII) and phosphinothricin resistance genes (bar) conferring resistance to kanamycin and PPT, respectively, as selectable markers and the sgfp-tyg gene for the green fluorescent protein (GFP) as a visual marker driven by the constitutive CaMV35S promoter in the presence
of acetosyringone (50 μM). Transformed shoots were obtained on MS Murashige and Skoog (Plant Physiol. 15: 473–497, 1962) medium supplemented with 1 mg L−1 benzyladenine (BA), 20 mg L−1
l-glutamine and 2 mg L−1 phosphinothricin (PPT) or 100 mg L−1 kanamycin. The regenerated shoots were examined in vivo using a hand-held long wave UV lamp for GFP expression. The GFP screening helped identify escapes and chimeric shoots at
regular intervals to increase the growth of transformed shoots on cotyledon explants. Elongation and rooting of putative transformants
were achieved on PPT (2 mg L−1) containing MS media with 0.5 mg L−1 gibberellic acid (GA3) and 0.6 mg L−1 indole butyric acid (IBA), respectively. PCR and Southern analyses confirmed the integration of the sgfp gene into the genome of T0 and the progenies. T1 segregation of transgenic progeny exhibited Mendelian inheritance of the transgene. The use of EHA105 resulted in 21% transformation
efficiency compared to 8.5% when LBA4404 was used. This higher rate was greatly facilitated by PPT selection coupled with
effective screening of transformants for GFP expression, thus making the protocol highly useful for the recovery of a higher
number of transgenic cucumber plants. 相似文献
16.
Jana Woelfel Rhena Schumann Florian Peine Anita Flohr Aleksandra Kruss Jaroslaw Tegowski Philippe Blondel Christian Wiencke Ulf Karsten 《Polar Biology》2010,33(9):1239-1253
During summer 2007, Arctic microphytobenthic potential primary production was measured at several stations around the coastline
of Kongsfjorden (Svalbard, Norway) at ≤5 m water depth and at two stations at five different water depths (5, 10, 15, 20,
30 m). Oxygen planar optode sensor spots were used ex situ to determine oxygen exchange in the overlying water of intact sediment
cores under controlled light (ca. 100 μmol photons m−2 s−1) and temperature (2–4°C) conditions. Patches of microalgae (mainly diatoms) covering sandy sediments at water depths down
to 30 m showed high biomass of up to 317 mg chl a m−2. In spite of increasing water depth, no significant trend in “photoautotrophic active biomass” (chl a, ratio living/dead cells, cell sizes) and, thus, in primary production was measured at both stations. All sites from ≤5 to
30 m water depth exhibited variable rates of net production from −19 to +40 mg O2 m−2 h−1 (−168 to +360 mg C m−2 day−1) and gross production of about 2–62 mg O2 m−2 h−1 (17–554 mg C m−2 day−1), which is comparable to other polar as well as temperate regions. No relation between photoautotrophic biomass and gross/net
production values was found. Microphytobenthos demonstrated significant rates of primary production that is comparable to
pelagic production of Kongsfjorden and, hence, emphasised the importance as C source for the zoobenthos. 相似文献
17.
Andreazza R Okeke BC Pieniz S Brandelli A Lambais MR Camargo FA 《Biological trace element research》2011,143(2):1182-1192
Environmental copper contamination is a serious human health problem. Copper reductase is produced by microorganisms to facilitate
copper uptake by ATPases into the cells increasing copper biosorption. This study assessed the reduction of Cu(II) by cell-free
extracts of a highly copper-resistant bacterium, Pseudomonas sp. strain NA, isolated from vineyard soil contaminated with copper. Both intact cells and cell-free extract of Pseudomonas sp. strain NA displayed substantial reduction of Cu(II). Intact cells reduced more then 80 mg L−1 of Cu(II) from medium amended with 200 mg L−1 of copper after 24 h of incubation. Cell-free extract of the isolate reduced more than 65% of the Cu(II) at initial copper
concentration of 200 mg L−1 after 24 h. Soluble protein production was high at 72 h of incubation at 100 mg L−1 of copper, with more then 60 μg L−1 of total soluble protein in cell-free extract recorded. Cu(II) reduction by isolate NA was increased when copper concentration
increased for both intact cells and cell-free extract. Results indicate that Pseudomonas sp. strain NA produces copper reductase enzyme as the key mechanism of copper biotransformation. 相似文献
18.
Hypocotyls explants of 1-week-old Ruta gravoelens L. seedlings showed high regeneration ability on Murashige and Skoog’s medium supplemented with 5.2 mM H2PO4
−, 250 mM adenine sulphate, 3.0% sucrose and 8.87 μM BA. Increasing phosphate and adenine sulphate concentrations had pronounced
effects on organogenesis and shoot growth compared to the stander MS medium. Multiple shoots were successfully maintained
for 60 days in static liquid medium without any hyperhydricity phenomena. Uncountable shoot buds and shoots were developed
on the leaf surface which was in contact with the medium. The growth index increased linearly during the culture course (R
2 = 0.992–0.999) and the highest GI (30.43) was achieved on medium enriched with 90 mM nitrogen and 4.5% sucrose. Medium supplemented
with 6.0% sucrose and 60 mM N yielded the highest biomass (4.37 g per flask). However, medium with the stander N content and
6.0% sucrose developed the maximum percentage of biomass (6.67%). The highest percentage of furanocoumarins (11.46 mg g−1 dry weight) calculated as xanthotoxin was produced in medium enriched with 90 mM N and 4.5 or 6.0% sucrose, whereas the maximum
rutin (73.5 mg g−1 dry weight) was on medium supplemented with 90 mM N and 4.5% sucrose. Developing system seems to be used for secondary metabolites
production because the shoot rooting did not appear. So, all energy is devoted for shoots multiplication, their growth and
secondary metabolites production. 相似文献
19.
Why Nitrogen Use Efficiency Decreases Under High Nitrogen Supply in Rice (Oryza sativa L.) Seedlings
Yong Li Xiuxia Yang Binbin Ren Qirong Shen Shiwei Guo 《Journal of Plant Growth Regulation》2012,31(1):47-52
Hydroponic experiments were conducted in a greenhouse to examine the effects of different nitrogen (N) supply (low, 20 mg L−1; intermediate, 40 mg L−1; and high, 100 mg L−1) on the growth, nitrogen use efficiency, and photosynthetic characteristics of rice seedlings (Oryza sativa L., cv. “Shanyou 63” hybrid indica. China). Leaf gas exchange was conducted to identify the photosynthetic-limiting factors in plants with high N supply. The
results showed that (1) shoot biomass, leaf area, and tiller numbers per plant under low N were lower than under intermediate
and high N supplies. No significant differences were observed between plants supplied with intermediate and high N. (2) About
a 35% increase in leaf N content in plants fed by high N resulted in about a 15% increase in carboxylation efficiency (CE)
and photosynthetic rate. (3) The noncorresponding increases in photosynthetic rate in rice seedlings fed by high N relative
to low N resulted from Rubisco activity and/or CE. (4) The decreased Rubisco activity was induced by a relatively insufficient
CO2 supply under high N supply. These results indicated that insufficient CO2 supply under high N supply accounted for the decreased Rubisco activity and the noncorresponding increases in photosynthetic
rate to leaf N content, and as a result, decreased (photosynthetic) nitrogen use efficiency. 相似文献
20.
Somatic embryogenesis and plant regeneration in two wild cotton species belong to G genome 总被引:1,自引:0,他引:1
Shu-Feng Yan Qiao Zhang Jing-Er Wang Yu-Qiang Sun M. K. Daud Shui-Jin Zhu 《In vitro cellular & developmental biology. Plant》2010,46(3):298-305
The present work describes the plant regeneration via somatic embryogenesis in two wild cotton species belonging to G genome:
Gossypium nelsonii Fryx and Gossypium australe F Muell. The role of plant hormones and carbohydrates was also evaluated for somatic embryogenesis and somatic embryo development.
Normal plants were obtained from G. nelsonii Fryx; abnormal plants and somatic embryos were obtained from G. australe F Muell. The best medium for callus induction for these G genome wild cotton species was MSB5 supplemented with 0.1 mg L−1 KT and 0.1 mg L−1 2,4-D. For embryogenic callus proliferation, the best medium used was MSB5 supplemented with 0.2 mg L−1 KT and 0.5 mg L−1 IBA. The medium MSB5 supplemented with 0.15 mg L−1 KT and 0.5 mg L−1 NAA was used successfully for root initiation and plant growth. In addition, adding CuSO4 and AgNO3 in the callus-inducing and proliferation medium resulted in a number of somatic embryos. Glucose and maltose, the carbon
sources in somatic culture, were used for callus induction, but maltose worked even better than glucose for proliferation
of embryogenic callus and development of somatic embryos. 相似文献