共查询到20条相似文献,搜索用时 15 毫秒
1.
Zheng Zhao Karel Kuijvenhoven Walter M. van Gulik Joseph J. Heijnen Wouter A. van Winden Peter J. T. Verheijen 《Applied microbiology and biotechnology》2011,89(1):63-72
The in vivo flux through the oxidative branch of the pentose phosphate pathway (oxPPP) in Penicillium chrysogenum was determined during growth in glucose/ethanol carbon-limited chemostat cultures, at the same growth rate. Non-stationary
13C flux analysis was used to measure the oxPPP flux. A nearly constant oxPPP flux was found for all glucose/ethanol ratios
studied. This indicates that the cytosolic NADPH supply is independent of the amount of assimilated ethanol. The cofactor
assignment in the model of van Gulik et al. (Biotechnol Bioeng 68(6):602–618, 2000) was supported using the published genome annotation of P. chrysogenum. Metabolic flux analysis showed that NADPH requirements in the cytosol remain nearly the same in these experiments due to
constant biomass growth. Based on the cytosolic NADPH balance, it is known that the cytosolic aldehyde dehydrogenase in P. chrysogenum is NAD + dependent. Metabolic modeling shows that changing the NAD + -aldehyde dehydrogenase to NADP + -aldehyde dehydrogenase can increase the penicillin yield on substrate. 相似文献
2.
Eric Mortreau Sonia Siljak-Yakovlev Malika Cerbah Spencer C. Brown Hélène Bertrand Claudie Lambert 《Tree Genetics & Genomes》2010,6(1):137-148
The subsection Asperae of genus Hydrangea L. (Hydrangeaceae) has been investigated for three reasons: several ambiguous classifications concerning Hydrangea aspera have been published, unexpected differences in genome size among seven accessions have been reported Cerbah et al. (Theor
Appl Genet 103:45–51, 2001), and two atypical chromosome numbers (2n = 30 for Hydrangea involucrata and 2n = 34 for H. aspera) have been found when all other species of the genus present 2n = 36. Therefore, these two species and four subspecies of Hydrangea in all 29 accessions were analyzed for their genome size, chromosome number, and karyotype features. This investigation includes
flow cytometric measurements of nuclear DNA content and bases composition (GC%), fluorochrome banding for detection of GC-
and AT-rich DNA regions, and fluorescent in situ hybridisation (FISH) for chromosome mapping of 5 S and 18 S-5.8 S-26 S rDNA
genes. In the H. aspera complex, the genome size ranged from 2.98 (subsp. sargentiana) to 4.67 pg/2C (subsp. aspera), an exceptional intraspecific variation of 1.57-fold. The mean base composition was 40.5% GC. Our report establishes the
first karyotype for the species H. involucrata, and for the subspecies of H. aspera which indeed present different formulae, offering an element of discrimination. FISH and fluorochrome banding revealed the
important differentiation between these two species (H. involucrata and H. aspera) and among four subspecies of the H. aspera complex. Our results are in agreement with the Chinese classification that places the groups Kawakami and Villosa as two
different species: Hydrangea villosa Rehder and Hydrangea kawakami Hayata. This knowledge can contribute to effective germplasm management and horticultural use. 相似文献
3.
Qiuxia Wang Congcong Liu Lili Xu Fangzhou Zhuang Bo Guan Guangcan Lin Chengdong Peng 《Zeitschrift fur angewandte Ichthyologie》2020,36(4):542-544
Parameters of the length-weight relationship (LWR) were estimated for four fish species [Beaufortia szechuanensis (Fang, 1930), Claea dabryi (Sauvage, 1874), Percocypris pingi (Tchang, 1930), and Yunnanilus sichuanensis Ding, 1995] from the Yalong River. Samples were collected seasonally from June 2018 to July 2019, using various fishing gears [set nets (mesh: 1.5 × 2.0 cm), hook, drift gill nets (three mesh sizes: 1.0; 2.0; 3.0 cm) and electro fishing]. Two new maximum standard length were recorded for C. dabryi and P. pingi. 相似文献
4.
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6.
Akio Shimizu Kagayaki Morishima Masahiro Kobayashi Masahiko Kunimoto Ichiro Nakayama 《Journal of applied phycology》2008,20(1):83-88
Conchospore germlings of Porphyra yezoensis were stained with a fluorescent dye for DNA and observed with confocal laser scanning microscopy (CLSM). Relative DNA values
of the germling nuclei were obtained by measuring fluorescence intensities of nuclear regions of the optically sliced specimens,
using the mean value of the smallest blade cells as a reference of the genomic n value. Such quantification revealed that the nuclear DNA amounts of the one-cell, two-cell, and four-cell-stage germlings
are approximately 4 × n, 2 × n, and n ∼2 × n values respectively; these values agreed well with the expected ones from the hypothesis that meiosis corresponds to the
first successive cell divisions after the conchospore germination. These results are consistent with a previous study on cytogenetic
analysis of the chimaera blade formation (Ohme and Miura 1988, Plant Sci 57:135–140) and not consistent with a recent microscopic study (Wang et al. 2006, Phycol Res 54:201–207) which proposed that the first meiotic division occurs at the conchospore formation and the second
division at the germination. 相似文献
7.
Eighteen specimens of Pimelodus maculatus collected from Tibagi River (Sertaneja, PR, Brazil) were analyzed cytogenetically. The diploid number of 56 chromosomes was
observed and karyotype was 20 M + 20 SM + 10 ST + 6 A with fundamental number (FN) of 106. Results of analyses from the nucleolus
organizer regions (NORs), obtained by AgNO3, CMA3 and C-band staining showed marking in a terminal position on the long arm of a pair of subtelocentric chromosomes. The restriction
enzyme AluI produced a linear differentiation similar to C-banding.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Rishi K. Tyagi Rajni Goswami Rajkumari Sanayaima Rakesh Singh Rajesh Tandon Anuradha Agrawal 《In vitro cellular & developmental biology. Plant》2009,45(6):721-729
Cardamom (Elettaria cardamomum Maton) has great commercial value as a spice crop in India. A one-step protocol for direct regeneration of plants and in vitro conservation by slow growth method has been developed. A maximum of 6.5 shoots/culture were obtained in 2 mo or 15.1 shoots/culture
in 4 mo on Murashige and Skoog (Physiol Plant 15:473–497, 1962) medium (MS) + 5 μM benzylaminopurine gelled with 0.7% agar (micropropagation medium). Rooting also occurred simultaneously
on the same medium. Using one shoot tip or nodal explant, about 30,375 plants can be regenerated in a year on the micropropagation
medium. In vitro conservation by slow growth method was achieved on 1/2 MS (major salts) + 5 μM BAP + 0.7% agar (conservation medium); about
70% of the cultures survived up to 18 mo at 25 ± 2°C. Successful regrowth of plants on micropropagation medium was obtained
by culturing nodal explants excised from 18-mo-old conserved plants. Some 96% of the plants survived the hardening treatment
and grew normally in a greenhouse. If 24 cultures are conserved on the conservation medium, it is possible to regenerate at
least 750 plants by using explants derived from 70% of the surviving shoots and culturing the same in micropropagation medium
for 4 mo. These plants may be used for planting or as a source of explants for the next conservation cycle. On the basis of
20 random amplified polymorphic DNA and 13 inter-simple sequence repeat primers analyses, no significant reproducible variation
was detected among the in vitro-conserved plants compared with the mother plants. 相似文献
9.
Xiaodong Li Myong Jong Yi Yowhan Son Pil Sun Park Kyeong Hak Lee Yeong Mo Son Rae Hyun Kim Mi Jeong Jeong 《Journal of Plant Biology》2010,53(6):381-386
Biomass expansion factors, which convert the timber volume (or dry weight) to biomass, are used to estimate the forest biomass
and account for the carbon budget at the national or regional level. This study estimated the biomass conversion and expansion
factors (BCEF), root to shoot ratio (R), biomass expansion factors (BEF) of natural Japanese Red Pine (Pinus densiflora Sieb. et Zucc.) forests based on direct field measurements and publications in Korea. This study attempted to fit the non-linear
relationships between the biomass expansion factors (BCEF and BEF) and main stand factors [stand age, tree height, and diameter
at breast height (DBH)]. The relationship between BEF and each main stand factor was expressed as a simple logarithmical equation.
The BCEF was also expressed as a logarithmical equation of the tree height, DBH, and stand volume, whereas there was no significant
relationship between BCEF and stand age. The mean value for BCEF, BEF, and R was 0.5821 Mg m−3 (n = 22, SD = 0.1196), 1.4465 (n = 22, SD = 0.2905), and 0.2220 (n = 17, SD = 0.0687), respectively. The values of the biomass expansion factors in this study may indicate much representativeness
to estimate forest biomass in natural Japanese Red Pine forests of Korea than the default values given by the IPCC (2003, 2006). 相似文献
10.
Under intracellular recording, we studied the effect of ATP on nerve cells of the rat intact nodose ganglion. The resting
membrane potential of the examined neurons was, on average, –60.3 ± 1.4 mV (n = 84); among such units, 88% were classified as C cells. Local application of 2 mM ATP to the surface of the ganglion using
a modified laminar flow system led to depolarization of neurons by 7.1 ± 0.9 mV, on average (n = 19). A blocker of P2X receptors, PPADS (100 μM), suppressed these depolarization responses, decreasing their amplitude,
on average, to 16 ± 3% (n = 3) of the initial value. The obtained data indicate that an overwhelming majority of neurons of the intact nodose ganglion
possess functional P2X receptors on their membranes. The absence of the corresponding responses in a considerable part of
neurons of intact spinal ganglia [13-15] was, apparently, determined by the fact that P2X receptors in the course of the described experiments had enough time to
desensitize before ATP reached the effective concentration. 相似文献
11.
Rong Pan Lixiang Cao Haiwei Huang Renduo Zhang Yu Mo 《Applied microbiology and biotechnology》2010,88(4):997-1005
In this study, dried and humid fruiting bodies of Tremella fuciformis and Auricularia polytricha were examined as cost-effective biosorbents in treatment of heavy metals (Cd2+, Cu2+, Pb2+, and Zn2+) in aqueous solution. The humid T. fuciformis showed the highest capacity to adsorb the four metals in the multi-metal solutions. The Pb2+ adsorption rates were 85.5%, 97.8%, 84.8%, and 91.0% by dried T. fuciformis, humid T. fuciformis, dried A. polytricha, and humid A. polytricha, respectively. The adsorption amount of Pb2+ by dried and humid T. fuciformis in Cd2+ + Pb2+, Cu2+ + Pb2+, Pb2+ + Zn2+, Cd2+ + Cu2+ + Pb2+, and Cd2+ + Zn2+ + Pb2+ solutions were not lower than that in Pb2+ solutions. The results suggested that in humid T. fuciformis, Cd2+, Cu2+, and Zn2+ promoted the Pb2+ adsorption by the biomass. In the multi-metal solutions of Cd2+ + Cu2+ + Pb2+ + Zn2+, the adsorption amount and rates of the metals by all the test biosorbents were in the order of Pb2+ > Cu2+ > Zn2+ > Cd2+. Compared with the pseudo first-order model, the pseudo second-order model described the adsorption kinetics much better,
indicating a two-step biosorption process. The present study confirmed that fruiting bodies of the jelly fungi should be useful
for the treatment of wastewater containing Cd2+, Cu2+, Pb2+, and Zn2+. 相似文献
12.
Naoya Kitao Daisuke Fukui Masaaki Hashimoto Peter G. Osborne 《International journal of biometeorology》2009,53(2):159-165
The raccoon dog, Nyctereutes procyonoides, is a canid with a passive overwintering strategy in northern Europe. However, the behaviour and physiology of the Japanese
subspecies, N. p. albus, which has fewer chromosomes than the other subspecies, remain unknown. We measured body temperature, body composition and
blood biochemistry of wild free-ranging and fasted enclosure-housed N. p. albus during boreal winter in Hokkaido, Japan. Body temperature of N. p. albus decreased from 38°C in autumn to 35.9–36.7°C while maintaining a circadian rhythm in late February (n = 3). A transient 18–36% decrease in resting heart rate occurred when body temperature was low (n = 2). Despite a 33–45% decrease in body weight due to winter fasting, circulating glucose, total protein and triglyceride
levels were maintained (n = 4). Serum urea nitrogen dropped by 43–45% from autumn to spring, suggesting protein conservation during fasting. The overwintering
survival strategy of N. p. albus in central Hokkaido is based upon large changes in seasonal activity patterns, winter denning and communal housing without
the large decrease in body temperature that is characteristic of subarctic animals exhibiting hibernation or torpor.
Naoya Kitao, Daisuke Fukui and Peter G. Osborne contributed equally to this work 相似文献
13.
Liapi C Zarros A Theocharis S Voumvourakis K Anifantaki F Gkrouzman E Mellios Z Skandali N Al-Humadi H Tsakiris S 《Biological trace element research》2011,143(3):1673-1681
Nickel (Ni) is an environmental pollutant towards which human exposure can be both occupational (mainly through inhalation)
and dietary (through water and food chain-induced bioaccumulation). The aim of this study was to investigate the effects of
short-term Ni-administration (as NiCl2, 13 mg/kg) on the adult rat whole brain total antioxidant status (TAS) and the activities of acetylcholinesterase (AChE),
Na+,K+-ATPase, and Mg2+-ATPase; in addition, the potential effect of the co-administration of the antioxidant L-cysteine (Cys, 7 mg/kg) on the above
parameters was studied. Twenty-eight male Wistar rats were divided into four groups: A (saline-treated control), B (Ni), C
(Cys), and D (Ni and Cys). All rats were treated once daily with intraperitoneal injections of the tested compounds, for 1-week.
Rats were sacrificed by decapitation and the above-mentioned parameters were measured spectrophotometrically. Rats treated
with Ni exhibited a significant reduction in brain TAS (-47%, p < 0.001, BvsA) that was efficiently limited by the co-administration of Cys (-4%, p > 0.05, DvsA; +83%, p < 0.001, DvsB), while Cys (group C) had no effect on TAS. The rat brain AChE activity was found significantly increased by
both Ni (+30%, p < 0.001, BvsA) and Cys (+62%, p < 0.001, CvsA), while it tended to adjust to control levels by the co-administration of Ni and Cys (+13%, p < 0.001, DvsA; −13%, p < 0.001, DvsB). The activity of rat brain Na+,K+-ATPase was significantly decreased by Ni-administration (−49%, p < 0.001, BvsA), while Cys supplementation could not reverse this decrease (-44%, p < 0.001, DvsA). The activity of Mg2+-ATPase was not affected by Ni-administration (−3%, p > 0.05, BvsA), but was significantly reduced when combined with Cys administration (−17%, p < 0.001, DvsA). The above findings suggest that Ni short-term in vivo administration causes a statistically significant decrease
in the rat brain TAS and an increase in AChE activity. Both effects can be, partially or totally, reversed to control levels
by Cys co-administration; Cys could thus be considered (for future applications) as a potential neuroprotective agent against
chronic exposure to Ni. The activity of Na+,K+-ATPase that was inhibited by Ni, could not be reversed by Cys co-administration. The matter requires further investigation
in order to fully elucidate the spectrum of the neurotoxic effects of Ni. 相似文献
14.
Tree species and wood ash application in plantations of short-rotation woody crops (SRWC) may have important effects on the
soil productive capacity through their influence on soil organic matter (SOM) and exchangeable cations. An experiment was
conducted to assess changes in soil C and N contents and pH within the 0–50 cm depth, and exchangeable cation (Ca2+, Mg2+, K+, and Na+) and extractable acidity concentrations within the 0–10 cm depth. The effects of different species (European larch [Larix decidua P. Mill.], aspen [Populus tremula L. × Populus tremuloides Michx.], and four poplar [Populus spp.] clones) and wood ash applications (0, 9, and 18 Mg ha−1) on soil properties were evaluated, using a common garden experiment (N = 70 stands) over 7 years of management in Michigan’s Upper Peninsula. Soils were of the Onaway series (fine-loamy, mixed,
active, frigid Inceptic Hapludalfs). The NM-6 poplar clone had the greatest soil C and N contents in almost all ash treatment
levels. Soil C contents were 7.5, 19.4, and 10.7 Mg C ha−1 greater under the NM-6 poplar than under larch in the ash-free, medium-, and high-level plots, respectively. Within the surface
layer, ash application increased soil C and N contents (P < 0.05) through the addition of about 0.7 Mg C ha−1 and 3 kg N ha−1 with the 9 Mg ha−1 ash application (twofold greater C and N amounts were added with the 18 Mg ha−1 application). During a decadal time scale, tree species had no effects—except for K+—on the concentrations of the exchangeable cations, pH, and extractable acidity. In contrast, ash application increased soil
pH and the concentration of Ca2+ (P < 0.05), from 5.2 ± 0.4 cmolc kg−1 (ash-free plots) to 8.6 ± 0.4 cmolc kg−1 (high-level ash plots), and tended to increase the concentration of Mg2+ (P < 0.1), while extractable acidity was reduced (P < 0.05) from 5.6 ± 0.2 cmolc kg−1 (ash-free plots) to 3.7 ± 0.2 cmolc kg−1 (high-level plots). Wood ash application, within certain limits, not only had a beneficial effect on soil properties important
to the long-term productivity of fast-growing plantations but also enhanced long-term soil C sequestration. 相似文献
15.
Galactosemic cataracts are characterized by electrolyte disturbances resulting in osmotic imbalance and loss of transparency.
We have studied the defensive role of quercetin, a bioflavonoid, against the alterations of calcium (Ca2+), sodium (Na+), and potassium (K+) concentrations in galactose-induced cataract in a rodent model. The experimental study was conducted on weanling male Wistar
rats with an average body weight of 34 ± 0.9 g. Different groups received normal stock AIN 93 diet (group A, n = 8), AIN 93 diet with 30% galactose (group B, n = 8), and AIN 93 diet with 30% galactose + quercetin at 400 mg/100 g diet (group C, n = 8). Aldose reductase activity and protein content and concentrations of Ca2+, Na+, and K+ were determined in normal and cataractous lenses. Treatment with quercetin resulted in a significant decrease in Na+ and Ca2+ and aldose reductase levels and an increase in K+ and protein levels in galactosemic cataractous lenses. These results imply that inclusion of quercetin contributes to lens
transparency through the maintenance of characteristic osmotic ion equilibrium and protein levels of the lens. 相似文献
16.
A series of crown ethers containing the azobenzene moiety incorporated into crowns of various sizes [Cr(O6), Cr(O7) and Cr(O8)] and their corresponding alkali metal cation (Li+, Na+, K+, Rb+) complexes have been studied theoretically. The density functional theory (DFT) method was employed to elucidate the stereochemical
structural natures and thermodynamic properties of all of the target molecules at the B3LYP/6-31 G(d) and LANL2DZ level for
the cation Rb+. The fully optimized geometries had real frequencies, thus indicating their minimum-energy status. In addition, the bond
lengths between the metal cation and oxygen atoms, atomic torsion angles and thermodynamic energies for complexes were studied.
Natural bond orbital (NBO) analysis was used to explore the origin of the internal forces and the intermolecular interactions
for the metal complexes. The calculated results show that the most significant interaction is that between the lone pair electrons
of electron-donating oxygens in the cis-forms of azobenzene crown ethers (cis-ACEs) and the LP* (1-center valence antibond lone pair) orbitals of the alkali-metal cations (Li+, Na+, K+ and Rb+). The electronic spectra for the cis-ACEs [cis-Cr(O6), cis-Cr(O7) and cis-Cr(O8)] are obtained by the time-dependent density functional theory (TDDFT) at the B3LYP/6-31 G(d) level. The spectra of the cis-isomers show broad π → π* (S0 → S2) absorption bands at 310–340 nm but weaker n → π* (S0 → S1) bands at 480–490 nm. The calculated results are in good agreement with the experimental results. 相似文献
17.
Avner Priel Arnolt J. Ramos Jack A. Tuszynski Horacio F. Cantiello 《Journal of biological physics》2008,34(5):475-485
Microtubules (MTs) are important cytoskeletal superstructures implicated in neuronal morphology and function, which are involved
in vesicle trafficking, neurite formation and differentiation and other morphological changes. The structural and functional
properties of MTs depend on their high intrinsic charge density and functional regulation by the MT depolymerising properties
of changes in Ca2 + concentration. Recently, we reported on remarkable properties of isolated MTs, which behave as biomolecular transistors capable
of amplifying electrical signals (Priel et al., Biophys J 90:4639–4643, 2006). Here, we demonstrate that MT-bathing (cytoplasmic) Ca2 + concentrations modulate the electrodynamic properties of MTs. Electrical amplification by MTs was exponentially dependent
on the Ca2 + concentration between 10 − 7 and 10 − 2 M. However, the electrical connectivity (coupling) of MTs was optimal at a narrower window of Ca2 + concentrations. We observed that while raising bathing Ca2 + concentration increased electrical amplification by MTs, energy transfer was highest in the presence of ethylene glycol tetraacetic
acid (lowest Ca2 + concentration). Our data indicate that Ca2 + is an important modulator of electrical amplification by MTs, supporting the hypothesis that this divalent cation, which
adsorbs onto the polymer’s surface, plays an important role as a regulator of the electrical properties of MTs. The Ca2 + -dependent ability of MTs to modulate and amplify electrical signals may provide a novel means of cell signaling, likely contributing
to neuronal function. 相似文献
18.
This paper aims to develop methods for quantifying their establishment; using physiological activity (chlorophyll as a growth
index and nitrogen-fixing potential as a measure of their biofertilizing capacity), along with evaluation based on DNA fingerprints
generated using repeat sequences/palindromes. Time course studies were undertaken in liquid and soil microcosm experiments
inoculated with a set of four rhizosphere cyanobacterial strains (BF1 Anabaena sp., BF2 Nostoc sp., BF3 Nostoc sp., BF4 Anabaena sp.). Observations revealed the synergistic effect of three-membered combinations (especially the i.e. BF1 + 2 + 3, 1 + 2 + 4,
1 + 3 + 4) in terms of enhancing chlorophyll and acetylene reducing activity. PCR-based amplification profiles (using short
tandemly repetitive repeat (STRR) 1A, STRRmod, and HIPAT sequences) proved discriminative in monitoring the presence of the inoculated cyanobacteria in soil microcosm. Future work
is in progress to assess the utility of the selected markers/primers in pot experiments, followed by field-level experiments
with crop. 相似文献
19.
Holcombe RF Jacobson J Dakhil SR Stewart RM Betzing KS Kannan K Macdonald JS 《Cancer immunology, immunotherapy : CII》1999,48(9):533-539
Levamisole (LMS), utilized in the adjuvant treatment of patients with stage III colon cancer, is immunomodulatory. To determine
whether alterations in immune parameters before, during and after 12 months of 5FU/LMS therapy correlate with disease-free
survival, 38 patients enrolled on Southwest Oncology Group (SWOG) protocol 8899 received extensive lymphocyte phenotypic analysis
prior to therapy and 3, 6, 12 and 15 months after treatment initiation. The median follow-up of patients is 41 months. Significant
increases in the proportion and total number of CD56+ natural killer cells were seen, starting at 3 months and continuing until 15 months (P < 0.001). Increases in the total numbers of cells expressing CD25 (interleukin-2 receptor), VLA4 and the combinations of CD4:
CD45RA and CD4:CDw29 were not evident during therapy but were seen at 15 months (P < 0.05: CD25, CD4:CDw29, CD4:CD45RA; P < 0.001: VLA4). Low levels of CD8+ cells prior to treatment initiation and after 3 months of therapy correlated with early relapse within the first year of
5FU/LMS treatment. Patients who have remained disease-free (n = 22, median follow-up 45 months) demonstrated increases in the total numbers of CD8+, CD25+, CD56+, VLA4+, CD4: CDw29 and CD4:CD45RA cells, primarily at 15 months. In contrast, patients who relapsed had decreased numbers of CD8+, CD4:CDw29, CD4: CD45RA and VLA4+ cells and minimal increases in CD56+ and CD25+ cells. Statistically significant differences between the late-relapse group and the group remaining disease-free were seen
for CD25+, CD4: CD45RA and CD4:CDw29 cells at the 15-month assay time (P = 0.0276, P = 0.0349, P = 0.0178 respectively). In conclusion, multiple alterations in lymphocyte phenotype, with increases in the proportion and total
number of cells involved in cell-mediated immune responses, were seen during and especially following completion of therapy
with 5FU/LMS. Many of these changes are significantly associated with clinical outcome and may be useful for risk stratification
of stage III colon cancer patients following completion of adjuvant therapy.
Received: 9 July 1999 / Accepted: 11 August 1999 相似文献
20.
The impacts of various nitrogen sources, i.e. NO−
3, NH4
+ or NH4NO3 in combination with gaseous NH3, on nitrogen-, carbon- and water-use efficiency and 13C discrimination (δ13C) by plants of the C3 species Triticum aestivum L. (wheat) and the C4 species Zea mays L. (maize) were studied. Triticum aestivum and Z. mays were hydroponically grown with 2 mol · m−3 of N supplied as NO−
3, NH4
+ or NH4NO3 for 21 and 18 d, respectively, and thereafter exposed to gaseous NH3 at 320 μg · m−3 or to ambient air for 7 d. In T. aestivum and Z. mays over a 7-d growth period, nitrogen-use efficiency (NUE) values were influenced by N-sources in the decreasing order NH4NO3-N > NO−
3-N > NH4
+-N and NO−
3-N > NH4NO3-N > NH4
+-N, respectively. Fumigation with NH3 decreased the NUE values of plants grown with any of the N-forms. During 28- and 7-d growth periods, N-sources affected water-use
efficiency (WUE) values in the decreasing order of NH4
+-N > NO−
3-N≈NH4NO3-N in non-fumigated T. aestivum, while fumigation with NH3 increased the WUE of NO−
3-grown plants. There were insignificant effects of N-sources on WUE values of Z. mays over 25- and 7-d growth periods. Furthermore, δ13C values in plant tissues (leaves, stubble and roots) were higher (less negative) in NH4
+-grown plants of T. aestivum and Z. mays than in those supplied with NH4NO3 or NO−
3. Regardless of the N-form supplied to the roots of the plant species, exposure to NH3 caused more-positive δ13C values in the plant tissues. These results indicate that the variations in N-source were associated with small but significant
variations in δ13C values in plants of T. aestivum and Z. mays. These differences in δ13C values are in the direction expected from differences in WUE values over long or short growth periods and with differences
in the extent of non-Rubisco (ribulose-1,5-bisphosphate carboxylase-oxygenase, EC 4.1.1.39) carboxylate contribution to net
C acquisition, as a function of N-source.
Received: 12 September 1997 / Accepted: 13 January 1998 相似文献