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1.
Botanical and chemical compositions of the rumen contents of 58 Sika deer on Mt Goyo, northern Japan, collected from summer
of 1988 to spring of 1989, were analyzed.Sasa nipponica, a dwarf bamboo, was important in summer (35.0%) and winter (61.4%), but it decreased to 5.6% and was replaced by browse
leaves in fall, and to 28.0% and was replaced by dead leaves, twigs and bark of woody plants in winter. Crude protein was
20–25% lower in the washed fraction than in the gross fraction. It was highest (16.2%) in summer and lowest (8.6%) in winter.
High protein content in summer and fall foods was attributed to forb and browse leaves. Seasonal fluctuation in protein content
in the foods of these Sika deer was greater than red deer on Rhum, Scotland and smaller than wapiti in Yellowstone National
Park, Wyoming, USA. Climatically, winter severity of Mt Goyo is intermediate between the two localities, which seems to explain
the seasonal fluctuation of the protein level. Crude fiber wasca 33% in the ‘washed’ fraction, and did not change seasonally. 相似文献
2.
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
3.
Enhanced nitrogen (N) deposition at high latitudes is a circumpolar phenomenon. Low soil phosphorus (P), however, may limit
vegetation responses to increased N inputs. From 2000 to 2002, the effects of N at 0, 0.5 (a rate occurring in Greenland and
Iceland) and 5 (equivalent to deposition in areas of Europe) g N m−2 a−1 and P (0.1 g m−2 a−1) treatments on plant species’ cover and diversity were determined at a polar semidesert site (ambient deposition c 0.1 g N m−2 a−1) in Svalbard (79°N). The largest response was to combined 5 g N plus 1 g P m−2 a−1, where cover of Saxifraga oppositifolia increased c fourfold, density of Salix polaris leaves c ninefold, seedlings of several ‘new’ species (Draba oxycarpa, Saxifraga caespitosa, Sagina nivalis) were established and ‘immigration’ of Bryum arcticum and ‘extinction’ of Schistidium apocarpum were observed. There were fewer, less pronounced, effects on the plant community at 0.5 g N m−2 a−1. Low P availability did indeed appear to restrict vegetation response to N. There was a trend for plant species’ richness
and diversity to increase with 1 g P m−2 a−1 at 0 and 0.5 g N m−2 a−1, but not at 5 g N m−2. Plant species showed individualistic responses so that generalisation by functional type was not possible. Such increased
colonisation by moss species of bare soil, and greater densities of previously unrecorded angiosperm seedlings, are not usually
observed in more closed (subarctic) tundra as a response to N and P additions. These changes are likely to influence significantly
nutrient cycles, whole system carbon budgets and surface energy and water balances.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
4.
Effects of Sika deer on the regeneration of aFagus crenata forest on Kinkazan Island,northern Japan 总被引:5,自引:0,他引:5
Kinkazan Island, a sanctuary island that has been conserved for over 100 years, is inhabited by a Sika deer population of
high density (60 km−2). AFagus crenata forest, a climax forest of this region, was composed of only large sized trees (30–60 cm diameter breast height) and lacked
young trees. However, many saplings were found inside a deer proof fence, indicating this forest had a potential to produce
seedlings. They were tentatively protected by shrubs ofLeucothoe grayana var.glabra, an upalatable ericaceous shrub, but did not exceed the shrub height. Heavy browsing by the deer suppressed recruitment of
saplings ofF. crenata. The forest will be reduced without population control of the deer. 相似文献
5.
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
6.
The effects of post harvest application of ethylene, abscisic acid (ABA), indole-3-butyric acid (IBA) treatments or dark storage
on root induction and continued growth of regenerated roots in Pelargonium cuttings were investigated using hydroponics in the greenhouse. Ethylene markedly increased rooting percentage in ‘Greco’
and ‘Surfing’, reduced the number of roots per cutting in ‘Surfing’ and had no effect on the total root lengths in the two
cultivars. Ethylene treatment reduced fresh root mass in ‘Surfing’, increased dry root mass and reduced root water content
in both cultivars. ABA (50 μM) enhanced rooting percentage in ‘Greco’, reduced the number of roots per cutting, reduced total
root lengths and fresh root mass in both cultivars. ABA increased dry root mass and reduced root water content in ‘Surfing’
but this effect was not apparent in ‘Greco’. Storing cuttings in the dark for 4 days had no effect on rooting percentage and
number of roots per cutting in ‘Greco’ and ‘Surfing’. However, dark storage reduced total root lengths in ‘Surfing’ and reduced
fresh root mass in ‘Greco’. Dark storage had no effect on dry root mass and water content in both cultivars. Applying 4 μl l−1 IBA in the rooting solution induced maximum (100%) root induction in ‘Surfing’. However, IBA reduced the number of roots
per cutting in ‘Greco’, reduced total root lengths and fresh root mass in the two cultivars. IBA treatment profoundly increased
and reduced dry root mass and root water content, respectively, in ‘Greco’ and ‘Surfing’. The enhanced root induction observed
after IBA and ABA applications could be ascribed to their influence on ethylene biosynthesis, since ethylene treatment increased
rooting percentage in both cultivars. However, high ABA (100 μM) and IBA (12 μl l−1) levels or dark storage reduced the ability of induced roots to continue growth. We attribute our results to plant stress-response
mechanism and ethylene appears to play an important role in the process of root initiation and root growth in Pelargonium cuttings. 相似文献
7.
C. Douglas Boyette Mark A. Jackson Charles T. Bryson Robert E. Hoagland William J. ConnickJr. Donald J. Daigle 《BioControl》2007,52(3):413-426
The weed Sesbania exaltata (Raf.) Rydb. ex A.W. Hill (hemp sesbania) was effectively controlled in soybean [Glycine max (L.) Merr.] field test plots over a 2-year testing period (1995–1996) with microsclerotia of the bioherbicidal fungus, Colletotrichum truncatum, formulated in wheat gluten-kaolin granules called ‘Pesta’. Weed control averaged 84% and 88%, respectively, in plots treated
pre-plant incorporated (PPI) at ‘Pesta’ rates of 168 or 336 kg ha−1, and 71% and 78%, respectively, in plots treated pre-emergence (PE) at ‘Pesta’ rates of 168 or 336 kg ha−1 over the testing period. Post-emergence (POE) control averaged 30% and 50%, respectively, for the 168 and 336 kg ha−1 treatments, and was significantly less effective than either PE or PPI treatments. Although pathogenesis and mortality occurred
in hemp sesbania tissues, satisfactory weed control was not achieved in plots treated at rates of 17 or 84 kg ha−1 with any of the application methods. Soybean yields were significantly greater in test plots treated PPI or PE, as compared
to yields from test plots treated either POE, with inert ‘Pesta’ granules, or from untreated controls. Microsclerotia formulated
in ‘Pesta’ granules exhibited excellent shelf-life, retaining high viability after storage for 10 years at 4 °C. These results
suggest that microsclerotia of C. truncatum formulated in ‘Pesta’ granules offers an effective method for controlling this important weed and preserving the activity
of this bioherbicide. 相似文献
8.
J. Masojídek M. Sergejevová K. Rottnerová V. Jirka J. Korečko J. Kopecký I. Zaťková G. Torzillo D. Štys 《Journal of applied phycology》2009,21(1):55-63
A novel two-stage experimental photobioreactor (PBR) with a total volume of 450 L and based uniquely on solar concentrators—linear
Fresnel lenses—has been constructed and tested. Daily courses of irradiance, and also its distribution inside cultivation
tubes, were studied in two unit types. The supra-high irradiance units in the ‘roof’ achieved a maximum summer value above
6 mmol photon m−2 s−1, while irradiance in the vertical-facade units was lower than ‘ambient’. In model cultivations, cultures of the cyanobacterium
Arthrospira platensis were cultivated at much higher solar irradiances than those usually recorded outdoors in summer, indicating that this organism
is resilient to high-irradiance (photoinhibition). Starting from a biomass density of 0.5 g L−1 at optimum temperature, the cultures grew exponentially. A two-stage cultivation process of the green microalga Haematococcus pluvialis was investigated with respect to correlations between photochemical activities and astaxanthin production. The culture was
first grown in low-irradiance units, and then exposed to supra-high irradiance when the rate of astaxanthin production was
30–50% higher than in the culture exposed to ‘ambient’ irradiance. Within 4 days, the astaxanthin content reached 3% of dry
weight, whereas under ambient irradiance the astaxanthin content was 25% lower. 相似文献
9.
Maternal and individual effects in selection of bed sites and their consequences for fawn survival at different spatial scales 总被引:1,自引:0,他引:1
Bram Van Moorter Jean-Michel Gaillard Philip D. McLoughlin Daniel Delorme François Klein Mark S. Boyce 《Oecologia》2009,159(3):669-678
We examined the relationship between survival of roe deer (Capreolus capreolus) fawns at Trois Fontaines, Champagne-Ardennes, France, and factors related to bed-site selection (predator avoidance and
thermoregulation) and maternal food resources (forage availability in the maternal home range). Previous studies have demonstrated
that at small scales, the young of large herbivores select bed sites independently from their mothers, although this selection
takes place within the limits of their mother’s home range. Fawn survival was influenced largely by the availability of good
bed sites within the maternal home range, not by the fawn’s selection of bed sites; however, selection for thermal cover when
selecting bed sites positively influenced survival of young fawns. Typical features of a good home range included close proximity
to habitat edges, which is related to forage accessibility for roe deer. The availability of bed sites changed as fawns aged,
probably due to an increased mobility of the fawn or a different use of the home range by the mother; sites offering high
concealment and thermal protection became less available in favor of areas with higher forage accessibility. Despite the minor
influence of bed-site selection on survival, roe deer fawns strongly selected their bed sites according to several environmental
factors linked to predator avoidance and thermoregulation. Fawns selected for sites providing concealment, light penetration,
and avoided signs of wild boar (Sus scrofa) activity. Avoidance of sites with high light penetration by young fawns positively affected their survival, confirming a
negative effect on thermoregulation due to reduced thermal cover. Selection for light penetration by older fawns was less
clear. We discuss these results in the context of cross-generational effects in habitat selection across multiple scales,
and the potential influence of the ‘ghost of predation past’. 相似文献
10.
C. M. Felland L. A. Hull B. A. Barrett A. L. Knight J. W. Jenkins P. A. Kirsch D. R. Thomson 《Entomologia Experimentalis et Applicata》1995,74(2):105-114
Mating disruption treatments for the tufted apple bud moth (TABM),Platynota idaeusalis (Walker), were tested in small plot trials in apple orchards in Pennsylvania. Treatments were evaluated by fruit injury and
by capture of male TABM in traps baited with synthetic pheromone sources or virgin females. The TABM pheromone is a two component
isomeric blend ofE-11-tetradecen-1-ol (E11-14:OH) andE-11-tetradecenyl acetate (E11-14:Ac). A 50∶50 ratio of these two components was used in standard monitoring septa and in mating
disruption treatments released from either hollow fibers (‘fiber’) or PVC tubes (‘PVC’). Other pheromone blends tested included
a 90∶10 ratio of E11-14: Ac and E11-14:OH (‘EAc’) and its reverse (‘EOH’), mixture ‘EAc’ with 30% of the Z-isomers (‘low AEc’),
and a blend similar to the preceding with 2% Z9-12:Ac (‘generic’). These other blends were released from multi tube tape (‘tape’)
or Shin-Etsu type rope (‘rope’) dispensers. Seasonal dispenser release rate in mg ha−1 h−1 was ca. 30 for the ‘rope’ dispensers, 14 for ‘PVC’ and 6 for ‘fiber’. ‘EAc-tape’ and ‘EOH-tape’ were equally effective in
reducing catches of males in traps baited with synthetic lures and in traps baited with virgin females. Both treatments also
reduced fruit injury. ‘EAc-rope’, ‘fiber’ and ‘PVC’ also were generally effective; whereas, the ‘low EAc’ and ‘generic’ treatments
reduced trap capture less than 90% and did not reduce fruit injury. Dispenser density was positively correlated with reduction
in trap capture for the ‘low EAc-rope’ and ‘genericrope’ treatments. Traps loaded with ‘fiber’ dispensers captured more male
TABM than the other treatments in non-pheromone permeated environments. Trap capture of other tortricids was reduced in pheromone
treatments. ‘EAc-rope’ and the ‘TABM’ treatments provided mean (s.e.) percent reduction in trap catch of 99.5 (0.4) and 42.9
(10.1), respectively, for the redbanded leafroller,Argyrotaenia velutinana (Walker), and 90.4 (6.8) and 90.4 (1.3), respectively, for the obliquebanded leafroller,Choristoneura rosaceana (Harris). 相似文献
11.
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
12.
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
13.
A. Q. Hurtado A. T. Critchley A. Trespoey G. Bleicher-Lhonneur 《Journal of applied phycology》2008,20(5):551-555
Kappaphycus striatum var. sacol was grown in two separate studies: (1) at two stocking densities, and (2) at four different depths, each for three different
durations of culture (30, 45 and 60 days) in order to determine the growth rate of the seaweed and evaluate the carrageenan
content and its molecular weight. The results demonstrated that stocking density, duration of culture and depth significantly
(P < 0.01) affected the growth rate, carrageenan content and molecular weight of K. striatum var. sacol. Decreasing growth rate was observed at both stocking densities and at four depths as duration of culture increased. A lower
stocking density (500 g m−1line−1) showed a higher growth rate for the shortest durations, i.e. 30 days, as compared to those grown at a higher density. Likewise,
decreasing growth rate was observed as depth increased, except at 50 cm after 60 days of culture. A 45-day culture period
produced the highest molecular weight at both stocking densities (500 g m−1line−1 = 1,079.5 ± 31.8 kDa, 1,000 g m−1line−1 = 1,167 ± 270.6 kDa). ‘Sacol’ grown for 30 days at 50 cm (1,178 kDa) to 100 cm (1,200 kDa) depth showed the highest values
of molecular weight of carrageenan extracted. The results suggested that K. striatum var. sacol is best grown at a stocking density of 500 g m−1line−1, at a depth of 50–100 cm, and for a duration of 30 days in order to provide the highest growth rate, carrageenan content
and molecular weight. 相似文献
14.
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
15.
Plant regeneration from callus culture of a Paphiopedilum hybrid 总被引:4,自引:0,他引:4
Totipotent calli of a Paphiopedilum hybrid (Paphiopedilum callosum ‘Oakhi’ × Paph. lawrenceanum ‘Tradition’) were induced from seed-derived protocorms on a 1/2 strength Murashige–Skoog medium plus 1–10 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.1–1 mg l−1 1-phenyl-3-(1.2.3-thiadiazol-5-yl)urea (TDZ). These calli grew well when subcultured on the same medium, but proliferated
more on 1/2 MS medium plus 5 mg l−1 2,4-D and 1 mg l−1 TDZ. Calli developed further along a route of production of protocorm-like bodies and eventually formed plantlets that could
be transplanted to pots and grew well.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
Hoffmann S Di Gaspero G Kovács L Howard S Kiss E Galbács Z Testolin R Kozma P 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(3):427-438
Vitis vinifera ‘Kishmish vatkana’, a cultivated grapevine from Central Asia, does not produce visible symptoms in response to natural or
artificial inoculation with the fungus Erysiphe necator Schwein., the casual agent of powdery mildew. ‘Kishmish vatkana’ allowed pathogen entry into epidermal cells at a rate comparable
to that in the susceptible control Vitis vinifera ‘Nimrang’, but was able to limit subsequent hyphal proliferation. Density of conidiophores was significantly lower in ‘Kishmish
vatkana’ (33.6 ± 8.7 conidiophores mm−2) than in ‘Nimrang’ (310.5 ± 24.0 conidiophores mm−2) by 120 h after inoculation. A progeny of 310 plants from a ‘Nimrang’ × ‘Kishmish vatkana’ cross were scored for the presence
or absence of visible conidiophores throughout two successive seasons. Phenotypic segregation revealed the presence of a single
dominant allele termed Resistance to Erysiphe necator 1 (REN1), which was heterozygous in ‘Kishmish vatkana’. A bulked segregant analysis was carried out using 195 microsatellite markers
uniformly distributed across the entire genome. For each marker, association with the resistance trait was inferred by measuring
in the bulks the ratio of peak intensities of the two alleles inherited from ‘Kishmish vatkana’. The phenotypic locus was
assigned to linkage group 13, a genomic region in which no disease resistance had been reported previously. The REN1 position was restricted to a 7.4 cM interval by analyzing the 310 offspring for the segregation of markers that surrounded
the target region. The closest markers, VMC9H4-2, VMCNG4E10-1 and UDV-020, were located 0.9 cM away from the REN1 locus.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
Wan-Jun Zhang Jiang-Li Dong Ben-Guo Liang Yong-Sheng Jin Tao Wang 《In vitro cellular & developmental biology. Plant》2006,42(2):114-118
Summary We report a protocol for efficient plant regeneration of four tall fescue (Festuca arundinacea Schreb.) cultivars (‘Surpro’, ‘Coronado’, ‘Summer Lawn’, and ‘Fawn’) via somatic embryogenesis. Calli were initiated from
mature seeds grown on modified Murashige and Skoog (MMS) medium supplemented with 7.0mgl−1 (31.7μM) 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.05 mgl−1 (0.23 μM) kinetin (Kin). Calli were maintained and proliferated by subculture at monthly intervals on MMS medium containing 4.5 mgl−1 (20.4 μM) 2,4-D and 0.2mgl−1 (0.9 μM) Kin. Somatic embryos (SE) were induced from seed-derived calli on SE-induction medium (MMS supplemented with 2.0 mgl−1 2,4-D and 0.2mgl−1 Kin). Plantlets were regenerated from somatic embryogenic calli grown on modified SH medium supplemented with 2 mgl−1 Kin. Using this optimized protocol, 78.6–82.3% of mature seeds of all four cultivars produced SE clusters, of which 93.5–95.3%
regenerated into plants within 10 wk. The regenerants showed no phenotypic abnormalities. 相似文献
18.
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
19.
The Florida Everglades is a naturally oligotrophic hydroscape that has experienced large changes in ecosystem structure and
function as the result of increased anthropogenic phosphorus (P) loading and hydrologic changes. We present whole-ecosystem
models of P cycling for Everglades wetlands with differing hydrology and P enrichment with the goal of synthesizing existing
information into ecosystem P budgets. Budgets were developed for deeper water oligotrophic wet prairie/slough (‘Slough’),
shallower water oligotrophic Cladium jamaicense (‘Cladium’), partially enriched C. jamaicense/Typha spp. mixture (‘Cladium/Typha’), and enriched Typha spp. (‘Typha’) marshes. The majority of ecosystem P was stored in the soil in all four ecosystem types, with the flocculent
detrital organic matter (floc) layer at the bottom of the water column storing the next largest proportion of ecosystem P
pools. However, most P cycling involved ecosystem components in the water column (periphyton, floc, and consumers) in deeper
water, oligotrophic Slough marsh. Fluxes of P associated with macrophytes were more important in the shallower water, oligotrophic
Cladium marsh. The two oligotrophic ecosystem types had similar total ecosystem P stocks and cycling rates, and low rates
of P cycling associated with soils. Phosphorus flux rates cannot be estimated for ecosystem components residing in the water
column in Cladium/Typha or Typha marshes due to insufficient data. Enrichment caused a large increase in the importance of
macrophytes to P cycling in Everglades wetlands. The flux of P from soil to the water column, via roots to live aboveground
tissues to macrophyte detritus, increased from 0.03 and 0.2 g P m−2 yr−1 in oligotrophic Slough and Cladium marsh, respectively, to 1.1 g P m−2 yr−1 in partially enriched Cladium/Typha, and 1.6 g P m−2 yr−1 in enriched Typha marsh. This macrophyte translocation P flux represents a large source of internal eutrophication to surface
waters in P-enriched areas of the Everglades. 相似文献
20.
Elevated [CO2], temperature increase and N supply effects on the turnover of below-ground carbon in a temperate grassland ecosystem 总被引:5,自引:0,他引:5
The effects of elevated [CO2] (700 μl l-1 CO2) and temperature increase (+3 °C) on carbon turnover in grassland soils were studied during 2.5 years at two N fertiliser
supplies (160 and 530 kg N ha-1 y-1) in an experiment with well-established ryegrass swards (Lolium perenne) supplied with the same amounts of irrigation water.
During the growing season, swards from the control climate (350 μl l-1 [CO2] at outdoor air temperature) were pulse labelled by the addition of 13CO2. The elevated [CO2] treatments were continuously labelled by the addition of fossil-fuel derived CO2 (13
C of -40 to -50 ‰). Prior to the start of the experimental treatments, the carbon accumulated in the plant parts and in the
soil macro-organic matter (‘old’ C) was at −32‰. During the experiment, the carbon fixed in the plant material (‘new’ C) was
at −14 and −54‰ in the ambient and elevated [CO2] treatments, respectively. During the experiment, the 13C isotopic mass balance method was used to calculate, for the top soil (0–15 cm), the carbon turnover in the stubble and roots
and in the soil macro-organic matter above 200 μ (MOM). Elevated [CO2] stimulated the turnover of organic carbon in the roots and stubble and in the MOM at N+, but not at N−. At the high N supply,
the mean replacement time of ‘old’ C by ‘new’ C declined in elevated, compared to ambient [CO2], from 18 to 7 months for the roots and stubble and from 25 to 17 months for the MOM. This resulted from increased rates
of ‘new’ C accumulation and of ‘old’ C decay. By contrast, at the low N supply, despite an increase in the rate of accumulation
of ‘new’ C, the soil C pools did not turnover faster in elevated [CO2], as the rate of ‘old’ C decomposition was reduced. A 3 °C temperature increase in elevated [CO2] decreased the input of fresh C to the roots and stubble and enhanced significantly the exponential rate for the ‘old’ C
decomposition in the roots and stubble. An increased fertiliser N supply reduced the carbon turnover in the roots and stubble
and in the MOM, in ambient but not in elevated [CO2]. The respective roles for carbon turnover in the coarse soil OM fractions, of the C:N ratio of the litter, of the inorganic
N availability and of a possible priming effect between C-substrates are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献