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1.
In order to study the responses of winter wheat cultivars released in different years to short-term high O3 exposure, an old cultivar (‘Nongda 311’, released in 1960s) and a modern one (‘Yannong 19’, released in 1990s) were treated
with an O3 exposure (145 ± 12 mm3 m−3, 4 h d−1 for 3 d) shortly after anthesis stage (> 50 % main stems blossomed). During the O3 exposure, light-saturated photosynthetic rate (P
N) and stomatal conductance (g
s) of both cultivars decreased considerably. Elevated O3 did not decrease dark-adapted maximum photochemical efficiency, but induced significant reduction in actual photochemical
efficiency and thereby considerably increase in non-photochemical quenching. P
N, g
s of the modern cultivar ‘Yannong 19’ decreased more than the older one ‘Nongda 311’, indicating the former exhibited higher
sensitivity to O3 than the latter. After O3 exposure, P
N, g
s and chlorophyll (Chl) content in flag leaf decreased more quickly than control, indicating induction of faster premature
leaf senescence. As a result, the short-term O3 exposure caused substantial yield loss, with larger reduction in ‘Yannong 19’ (−19.2 %) than in ‘Nongda 311’ (−8.4 %). Our
results indicated that high O3 exposure at grain filling stage would have greater negative impacts on the high yielding modern cultivar relative to the
old one with lower yield. 相似文献
2.
Barbara Duquenne Tom Eeckhaut Stefaan Werbrouck Johan Van Huylenbroeck 《Plant Cell, Tissue and Organ Culture》2007,91(2):165-173
Vital protoplasts from Spathiphyllum wallisii ‘Alain’ and Anthurium scherzerianum ‘238’ were isolated from both somatic embryos and leaves. The highest yields were obtained when 1.5% cellulase, 0.5% macerase
and 0.5% driselase were used for Spathiphyllum wallisii leaves and 0.5% cellulase, 0.3% macerase and 0.5% driselase for Anthurium scherzerianum embryos. About 1 × 106 protoplasts g−1 and 1 × 105 protoplasts g−1 could be isolated from leaves and embryos, respectively. For protoplast fusion Spathiphyllum wallisii ‘Alain’ and Anthurium scherzerianum ‘238’ were mixed in a 1:1 ratio in a fusion solution containing 1 mM CaCl2·2H2O, 1 mM MES and 0.5 M mannitol. Fusion was performed by protoplast alignment under 500 V cm−1 alternating current for 60 s and subsequent generation of two pulses of 4500 V cm−1 direct current during 50 μs. Development until colony stage was achieved using agarose beads for protoplast culture. 相似文献
3.
The feeding dynamics and oxygen uptake of the bottom-dwelling caridean shrimp Nauticaris marionis were studied during the April/May 1984, 1996 and 1997 cruises to Marion Island (Prince Edward Islands, Southern Ocean). N. marionis is thought to have an opportunistic feeding mode. Prey composition varied considerably between the years and sites investigated.
Overall, benthic (mainly hydrozoans and bottom-dwelling polychaetes) and, at times, pelagic (largely euphausiids and copepods)
prey items dominated in the stomachs of N. marionis both by occurrence and by volume. Generally, pelagic prey contributed more to the diets of smaller shrimps, while benthic
prey was a more important component in the guts of larger specimens. Wet, dry and ash-free dry weight were determined for
specimens used in respiration experiments. The respiration rates of N. marionis females with carapace length 6.6–11.1 mm ranged from 80 to 250 μl O2 individual−1 · h−1, or from 0.588 to 2.756 μl O2 · mg−1 dry weight h−1. Regression analyses showed highly significant correlations between oxygen consumption and carapace length for N. marionis. Daily ingestion rates estimated using an in situ gut content analysis technique (4.4% of body dry weight) and an energy budget approach (average 4.7% of body dry weight,
range 2.0–7.5%) showed good agreement with each other.
Accepted: 29 July 1998 相似文献
4.
Dimitris Petroutsos Petros Katapodis Paul Christakopoulos Dimitris Kekos 《Journal of applied phycology》2007,19(5):485-490
The ability of Tetraselmis marina, a green coastal microalga, to remove chlorophenols under photoautotrophic conditions was investigated. T.marina was able to grow in the presence of 20 mg L−1 of the phenolic compounds tested. The EC50 (growth rate) value of p-chlorophenol (p-CP) to T.marina was found to be 25.5 mg L−1. The microalga was able to remove chlorophenols, showing higher efficiency for p-CP. The effect of photoregime and NaHCO3 concentration on p-CP removal was investigated. Under continuous illumination with 1 g L−1 NaHCO3 initial concentration T.marina removed 65% of 20 mg L−1 in a 10-day cultivation period. 相似文献
5.
The phagotrophic flagellate Oxyrrhis marina shows a strong stoichiometric plasticity when fed differently grown Rhodomonas salina. We tested whether differently pre-conditioned O. marina displayed selective feeding behaviour from a mixture of nitrogen and phosphorus depleted R. salina. We observed selective feeding of O. marina, always selecting phosphorus rich R. salina independent of the pre-conditioning of the protists. In a second experiment, O. marina was again pre-conditioned either with nitrogen- or phosphorus-depleted R. salina and was refed with either of the differently limited R. salina in single food treatments (not in a mixture). The phagotrophic flagellate displayed compensatory feeding which means that
O. marina feed more on the food source which they were not given before. Due to its stoichiometric plasticity, O. marina might handle bad quality food by following the stoichiometry of its prey and additionally by active selective feeding towards
P-rich algae to enhance growth. Post-ingestion selection might as well be an important feature which means that ingested elements
in excess are quickly excreted and scarce elements are ingested through accelerated food uptake. 相似文献
6.
Kerstin Hauschild Manfred K. Grieshaber 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(5):378-388
The lugworm Arenicola marina is a typical inhabitant of intertidal flats. In its L-shaped burrow the animal is exposed to varying concentrations of O2 and toxic sulfide depending on the tides. The lugworm is able to detoxify sulfide through its oxidation to thiosulfate. When
exposed to declining O2 tensions Arenicola marina reacted as an oxyconformer. In the presence of 25 μmol · l−1 sulfide the respiration was not affected. In contrast, the lugworm consumed significantly less O2 at any Po2 in the presence of 200 μmol · l−1 sulfide. Without sulfide anaerobic metabolism started at a Po2 of approximatedly 10 kPa. Even at high O2 tensions animals exposed to sulfide produced significantly more anaerobic metabolites compared with the controls. Accordingly
the critical value PcM, the ambient Po2 below which anaerobic metabolism starts, was shifted towards normoxia. Since O2 supply was sufficient for aerobic metabolism, anaerobiosis was induced by sulfide. An influx of sulfide was observed at 25
as well as at 200 μmol · l−1 sulfide. The main product of sulfide detoxification in the lugworm was thiosulfate. Its synthesis increased with ambient
Po2 and depended on the sulfide concentration. Sulfide and thiosulfate were detected in the coelomic fluid, the blood, and the
body wall of Arenicola marina. Only about 2% of the ambient O2 was used for sulfide detoxification at 25 μmol · l−1 sulfide and about 50% at 200 μmol · l−1 sulfide, respectively. Even at the low sulfide concentration Arenicola marina's capacity to detoxify sulfide was too low to maintain a complete aerobic metabolism.
Accepted: 19 February 1997 相似文献
7.
Annual cycle of gross primary production and respiration in the Viroin River (Belgium) 总被引:1,自引:1,他引:0
Gross primary production, community respiration and reaeration coefficient were determined during an annual cycle on the Viroin
River (South Belgium), based on the daily variations of dissolved oxygen concentration.
Reaeration coefficient remains remarkably constant (0.26 h−1) during the year in spite of discharge variations. The autotrophic community is dominated by ‘Ranunculus fluitans’. Primary production parallels the variations of total solar radiations. It ranges from 0 in winter to 8 g O2 m−2 d−1 in summer. In spring and summer, respiration variations parallel those of primary production (average value: 10 g O2 m−2 d−1); in the dry autumn, decomposition of dying macrophytes considerably enhances the community respiration (15 g O2 m−2 d−1).
A P/R diagram is used to characterize the trophic state of the Viroin. 相似文献
8.
Summary Use of lysozyme was tested for treatment of bacterial contaminations in in vitro shoot cultures of quince (Cydonia oblonga) ‘BA 29’ and the hybrid (Prunus persica × P. amygdalus) rootstock ‘GF 677’. Shoots which had been contaminated for about 1 yr by Bacillus circulans and Sphingomonas paucimobilis were treated in liquid culture, at pH 4.5, with 9–36 mg ml−1 egg white lysozyme (EWL), and compared to each other and to untreated cultures for their growth, proliferation, and number
of bacterial colony-forming units in the tissues. EWL did not negatively affect shoot growth up to 18 mg ml−1; furthermore, the proliferation rates of EWL-treated shoots were sometimes higher than those of controls. In contrast, the
concentration of 36 mg ml−1 had some deleterious effect on the regrowth capacity and shoot production of ‘GF 677’ at the first subculture to solid medium
after EWL, treatments. EWL had a simple bacteriostatic effect against Sphingomonas paucimobilis; in contrast, it was effective at 18 mg ml−1 in eliminating Bacillus circulans in both ‘BA 29’ and ‘GF 677’ cultures, after optimal treatment duration. 相似文献
9.
Theophilus M. Mutui Vallantino E. Emongor Margaret J. Hutchinson 《Plant Growth Regulation》2006,48(3):207-214
Leaf yellowing is a major problem in Alstroemeria and absence of leaf senescence symptoms is an important quality attribute. Two Alstroemeria cultivars ‘Yellow King’ and ‘Marina’ were sourced from a commercial farm and harvested when sepals began to reflex. Stems
were re-cut under water and kept in vase solutions of gibberellin A4+7 (0, 2.5, 5.0, 7.5, 10.0, 12.5 or 15.0 mg l−1 [Provider]). Treatments and cultivars were combined in a factorial fashion and arranged in a completely randomised design. Application
of GA4+7 in the holding solution at 2.5–10.0 mg l−1 significantly delayed the onset of leaf senescence by around 7 days and significantly increased days to 50% petal fall by
ca. 2 days. Additionally, these GA4+7 concentrations resulted in higher retention of leaf nitrogen, leaf chlorophyll and also increased leaf water content, while
reducing leaf dry weight, all relative to untreated controls. Cultivar ‘Yellow King’ had significantly longer vase life and
a better retention of leaf quality than ‘Marina’. Our results suggest that a concentration of 10 mg l−1 GA4+7 can be used to prolong vase life, delay leaf senescence and enhance post-harvest quality of Alstroemeria cut flowers during their transport to market. 相似文献
10.
Summary Carbohydrate type and concentration and their interactive effects on in vitro shoot proliferation of three lingonberry (Vaccinium vitis-idaea ssp. vitis-idaea L.) cultivars (‘Regal’, ‘Splendor’, and ‘Erntedank’) and two V. vitis-idaea ssp. minus (Lodd) clones (‘NL1’ and ‘NL2’) were studied. Nodal explants were grown in vitro on medium with 2 μM zeatin and either glucose, sorbitol, or sucrose at a concentration of 0, 10, 20, or 30 gl−1. The interactive effects of carbohydrate type and concentration and genotype were important for shoot proliferation. The
best response was afforded by sucrose at 20 gl−1 both in terms of explant response and shoot developing potential, although glucose supported shoot growth equally well, and
in ‘NL1’ at 10 gl−1 it resulted in better in vitro growth than sucrose. Carbohydrate concentration had little effect on shoot vigor. The genotypes differed in terms of shoots
per explant, length, and vigor, leaves per shoot, and callus formation at the base of explants; this was manifested with various
types and concentrations of carbohydrate. Changing the positioning of explants on the medium from vertically upright to horizontal
increased the shoot and callus size, but decreased shoot height and leaves per shoot. Proliferated shoots were rooted on a
peat:perlite (1∶1, v/v) medium and the plantlets were acclimatized and eventually established in the greenhouse. 相似文献
11.
O. Boussadia K. Steppe H. Zgallai S. Ben El Hadj M. Braham R. Lemeur M. C. Van Labeke 《Photosynthetica》2011,49(1):149-153
For Tunisian olive tree orchards, nitrogen deficiency is an important nutritional problem, in addition to the availability
of water. Establishment of relationships between nutrients such as nitrogen and ecophysiological parameters is a promising
method to manage fertilisation at orchard level. Therefore, a nitrogen stress experiment with one-year-old olive trees (Olea europaea L. ‘Koroneiki’ and ‘Meski’) was conducted with trees respectively subjected to four nitrogen supply regimes (23.96 meq l−1, 9.58 meq l−1, 4.79 meq l−1 and 0 meq l−1 NO3
−1). 相似文献
12.
The marine diatom Haslea ostrearia Simonsen produces a blue pigment, marennine, which is used for greening oysters. This microalga is cultured industrially
indoors with artificial light. The influence of light quality on marennine production by cultures of H. ostrearia was investigated in the laboratory and at a semi-pilot scale (300 L tanks). In the first series of experiments in the laboratory,
a clone of H. ostrearia was cultured under light of different colors (white, blue, green, yellow, and red) and at two irradiances (‘low’ and ‘high’,
20 and 100 μmol photons m−2 s−1, respectively). Compared to the white light controls, growth was increased in blue light at the ‘low’, but not at the ‘high’
irradiance, and marennine production at the end of the exponential phase was the highest in cells grown under blue light,
regardless of the light quality or intensity during growth. Increased marennine production during growth was also observed,
whichever color of light (blue or white) was used during the acclimation phase. In a second series of experiments, intraclonal
differences were studied by comparing marennine production in seven clones differing with regard to their mean cell size.
The total marennine expressed either per cell or per culture volume, was higher in blue light for all the clones. Complementary
experiments carried out under semi-industrial conditions confirmed this effect of blue light, which could be relevant for
the industrial, indoor production of marennine. 相似文献
13.
During January/February 2006, we satellite-tracked two different ecotypes of killer whales (Orcinus orca) in McMurdo Sound, Ross Sea, Antarctica, using surface-mounted tags attached with sub-dermal darts. A single Type B whale
(pinniped prey specialist), tracked for 27 days, traveled an average net distance of 56.8 ± 32.8 km day−1, a maximum of 114 km day−1, and covered an estimated area of 49,351 km2. It spent several days near two large emperor penguin (Aptenodytes forsteri) colonies, a potential prey item for this form. By contrast, four Type C killer whales (fish prey specialists) tracked for
7–65 days, traveled an average net distance of 20 ± 8.3 km day−1, a maximum of 56 net km day−1, and covered an estimated area of only 5,223 km2. These movement patterns are consistent with those of killer whale ecotypes in the eastern North Pacific where mammal-eating
‘transients’ travel widely and are less predictable in their movements, and fish-eating ‘residents’ have a more localized
distribution and more predictable occurrence, at least during the summer months. 相似文献
14.
Alginate production by Azotobacter vinelandii growing in chemostat cultures was evaluated under different O2 transfer rates (OTR). As a result of modifying the culture’s agitation rate from 300 to 500 rpm, the OTR increased from 9
to 15.1 mmol l−1 h−1 and a slight variation in the alginate production (1.7–2.2 g l−1) was observed. At a constant growth rate (0.1 h−1), the mean molecular mass of the alginate was strongly influenced by changes in the OTR, varying from 860 to 1,690 kDa. These
results support a possible relationship between alginate polymerization-depolymerization process and the O2 uptake rate. 相似文献
15.
J. Y. Choi H. J. Kim C. H. Lee J. M. Bae Y. S. Chung J. S. Shin N. I. Hyung 《In vitro cellular & developmental biology. Plant》2001,37(2):274-279
Summary An efficient and simple plant regeneration system via organogenesis from leaf segments of persimmon (Diospyros kaki Thunb.) cultivars ‘Fuyu’ and ‘Nishimurawase’ has been developed. The regeneration capacity was influenced by the culture
vessels, gelling agents, plant growth regulators, and light conditions. Leaf explants taken from in vitro shoots were cultured on a modified Murashige and Skoog medium (MS1/2N), for 16 wk without transfer to fresh medium. Adventious
shoots appeared after 4 and 8 wk in culture of ‘Nishimurawase’ and ‘Fuyu’ tissues, respectively. The culture of leaf explants
in Erlenmeyer flasks with medium containing 4 g l−1 agar enhanced shoot formation in comparison to media with increased agar concentrations. Optimal shoot regeneration was obtained
with 5 mg l−1 (22.8 μM) zeatin and 0.1 mg l−1 (0.05 μM) indole-3-butyric acid (IBA) for ‘Nishimurawase’, and 10 mg l−1 (45.6 μM) zeatin and 0.1 mg l−1 (0.05 μM) IBA for ‘Fuyn’. Shoot regeneration frequencies in both cultivars were 100%, and shoot numbers per explant reached up to
9.2 for ‘Nishimurawase’ and 2.2 for ‘Fuyu’. Dark incubation during the first 4–5 wk was the most effective condition to successfully
influence shoot regeneration in both cultivars. While dark incubation was essential for adventitious shoot formation by ‘Fuyu’,
it was only slightly beneficial to ‘Nishimurawase’. More than 80% of the regenerated shoots rooted within 4 wk on hormone-free
MS1/2N demium after having been dipped for 30 s in 250 mg l−1 (1.1. mM) IBA solution. 相似文献
16.
Wen Liu Xuesen Chen Guanjun Liu Qing Liang Tianming He Jianrong Feng 《Plant Cell, Tissue and Organ Culture》2007,88(3):289-299
Embryo rescue technique was used successfully to produce interspecific hybrids by crossing peach (P. persica) as a female parent with apricot (P. armeniaca) and plum (P. salicica). In those crosses that had ‘Yuhualu’ or ‘Zhonghuashoutao’ as female parents, hybrid embryos aborted from the 7th or 8th
week after pollination mainly due to post-pollination incompatibility. An embryo rescue protocol was established to rescue
such embryos and recover hybrid plants. Modified half-strength MS medium containing 4 mg l−1 6-BA and 0.5 mg l−1 IBA produced up to 90% germination in the embryos. Modified MS medium with 1.0 mg l−1 6-BA and 1.0 mg l−1 IBA gave the highest bud induction and multiplication whereas modified MS medium containing 0.5 mg l−1 IAA and 0.2 mg l−1 NAA gave the best rooting percentage. All the hybrids obtained using this embryo rescue technique were verified using simple
sequence repeat (SSR) markers. A series of pollen treatments were carried out to partially overcome pre-pollination incompatibility,
and it was found accidentally that pollen treatment with electrostatic field not only improved pollen germination but also
increased the multiplication coefficient of embryo-induced shoots. 相似文献
17.
Breeding linseed (Linum usitatissimum L.) using haploid techniques allows breeders to develop new cultivars in a shorter time period. Many research groups successfully
created new linseed genotypes through anther culture; however ovary culture has been the subject of only a few earlier studies.
In the present study, the effect of genotype and growth regulators combination on callus induction and shoots regeneration
in ovary culture of nine commercially important linseed cultivars was investigated. Ovaries were cultured on modified MS medium
supplemented with three different combinations of plant growth regulators. Variable callogenic responses were expressed by
all of the genotypes tested on different induction media. The results suggested that specific combination of growth regulators
for callus induction must be designed for each genotype. Shoot regeneration from ovary derived callus is a critical phase
of the whole gynogenetic process. Differences in adventitious shoot formation frequency among genotypes were demonstrated
and four responsive genotypes have been selected. Ovary derived callus from cultivar ‘Mikael’ manifested the highest adventitious
shoot formation frequency with a high number of shoots per explant. The optimum ratio of growth regulators for shoot regeneration
was shown to depend on the genotype. Cultivars ‘Linola’, ‘Mikael’ and ‘Szaphir’ showed the highest shoot regeneration frequency
when callus had originated on induction medium supplemented with 2 mg L−1 BAP and 2 mg L−1 NAA, while combination of 1 mg L−1 BAP and 2 mg L−1 IAA promoted shoot formation in ovary-derived callus of ‘Barbara’. The highest rate of shoots per explant has been obtained
in second subculture. 相似文献
18.
Antarctic marine organisms are considered to have extremely limited ability to respond to environmental temperature change.
However, here we show that the Antarctic notothenioid fish Pagothenia borchgrevinki is an exception to this theory. P. borchgrevinki was able to acclimate its resting metabolic rate and resting ventilation frequency after a 5°C rise in temperature. Acute
exposure to 4°C resulted in an elevation in metabolic rate (57.8 ± 4.79 mg O2 kg−1 h−1) and resting ventilation rate (40.38 ± 1.61 breaths min−1) compared with fish at −1°C (metabolic rate 34.45 ± 3.12 mg O2 kg−1 h−1; ventilation rate 29.88 ± 3.72 breaths min−1). However, after a 1-month acclimation period, there was no significant difference in the metabolic rate (cold fish 29.52 ± 3.01;
warm fish 31.13 ± 2.30 mg O2 kg−1 h−1), or the resting ventilation rate (cold fish 28.75 ± 0.98; warm fish 34.25 ± 2.28 breaths min−1) of cold and warm acclimated fish. Acclimation changes to the rate of oxygen consumption following exhaustive exercise were
complex. The pattern of oxygen consumption during recovery from exhaustive exercise was not significantly different in either
cold or warm acclimated fish. 相似文献
19.
The zooplankton off the north-east coast of England has been the subject of a number of studies focusing on its productivity.
It has also been shown to be representative of the zooplankton of much of the western North Sea. The community contains a
number of predatory species, three of which are widely described as ‘voracious’, the ctenophorePleurobrachia pileus, the chaetognathSagitta elegans and the hyperiid amphipodThemisto compressa (≡ Parathemisto gaudichaudi). This study investigates the role of these planktonic predators in this community, with special reference to the seasonal
changes in predation pressure.
The functional response ofPleurobrachia pileus feeding onAcartia was determined from laboratory experiments. It was found to be linear at prey densities typical of UK coastal waters, although
the linear relationship appeared to break down at low and high prey densities.
Feeding rate data forSagitta elegans were obtained from gut content analysis and published laboratory derived estimates of digestion time. Of the 1,789 individuals
examined 198 (11.1%) had food remains in the gut. A linear relationship betweenSagitta length and prey size was established and the daily feeding rate ofSagitta elegans was estimated to be 0.4 prey items d−1 ind−1.
For comparative purposes, the proportion of the copepod standing stock removed bySagitta elegans, Pleurobrachia pileus andThemisto gaudichaudi was estimated for each month of the year. From this model it was shown thatThemisto applied the most predation pressure, andSagitta elegans applied the least predation pressure of the three planktonic predators considered. The impact ofPleurobrachia will be to a large extent offset due to its peak of seasonal abundance coinciding with the zooplankton peak in the summer. 相似文献
20.
Siphonophores are exclusively marine cnidaria and their predatory role in plankton food-webs is well recognised. In this study,
we analyse the structure and the spatial extent of siphonophore assemblages in relation to changes in freshwater outflows
and food availability in the southern Gulf of Mexico during a high (October) and a low (April) outflow periods. A total of
149 samples were collected using a 505 μm multiple closing net at 1–6 levels (0–100 m) of the water column, depending on the
bathymetry. Data on siphonophore species biovolumes (ml 100 m−3) were treated by means of the Bray-Curtis Dissimilarity Index, and two distinctive assemblages were identified: the ‘inner’
and the ‘outer’ assemblages, located over the inner and outer shelves. Temperature, salinity, zooplankton biomass, and siphonophore
species were included in a Principal Component Analysis (PCA) to identify the factors associated with each assemblage. Geographical
distribution of the assemblages practically remained the same during both seasons and its cross-shelf variability was stronger
than the vertical one. Seasonally, diversity values were higher in October, when the highest river discharges occur. Spatially,
the lowest diversity and mean siphonophore biovolumes values were registered in the ‘inner assemblage’, where the highest
and lowest salinity values were recorded. We suggest that even when extreme salinity values (>36.5 or <34) might depress siphonophore
populations in the coastal area, enough food availability in the concerned areas might mitigate the negative effect of salinity,
since a positive and significant (p < 0.05) relationship was found between siphonophores biovolume and zooplankton biomass. Bassia bassensis, Diphyes dispar and Enneanogum hyalinum, present in both assemblages during both seasons, were able to survive in a wide range of salinity values, following perhaps,
their prey. All the 23 species here registered were found in the ‘outer assemblage’; however, Abylopsis eschscholtzi, Chelophyes appendiculata and Diphyes bojani were more associated with the ‘outer’ group according to the PCA results. Enneagonum hyalinum was the only species frequently encountered and abundant in the ‘inner assemblage’ during both seasons and, supporting previous
observations, this species might be considered as an indicator of nearshore waters.
Handling editor: K. Martens 相似文献