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1.
Petunia × hybrida was grown under high (H), medium (M) and low (L) light intensity [photoperiod; 16 h d −1, photosynthetic photon flux density (PPFD); 360, 120 and 40 μmol m −2 s −1, respectively] as well as under end-of-day (EOD) red (R) and far-red (FR) light quality treatments [photoperiod; 14.5 h d −1, PPFD; 30 μmol m −2 s −1 EOD; 15 min, Control (C) light; without EOD light treatment]. Shoot growth, leaf anatomical and photosynthetic responses
as well as the responses of peroxidase (POD) isoforms and their specific activities following transition to flowering (1–6 weeks)
were evaluated. Flower bud formation of Petunia × hybrida was achieved at the end of the 4th week for H light treatment and on the end of the 6th week for FR light treatment. No flower
bud formation was noticed in the C and R light treatments. H and M light treatments induced lower chlorophyll (Chla, Chlb,
Chla+b) concentrations in comparison to L light. On the other hand R and FR light chlorophyll content were similar to C light.
Photosynthetic parameters [CO 2 assimilation rate ( A), transpiration rate ( E) and stomatal conductance ( g
s) values] were higher in the H light treated plants in comparison to M and L light treated plants. A, E and g
s values of R and FR light were similar to C light plants. Leaf anatomy revealed that total leaf thickness, thickness of the
contained tissues (epidermis, palisade and spongy parenchyma) and relative volume percentages of the leaf histological components
were differently affected within the light intensity and the light quality treatments. POD specific activities increased from
the 1st to the 6th week during transition to flowering. Native-PAGE analysis revealed the appearance of four anionic POD (A 1–A 4) isoforms in all light treatments. On the basis of the leaf anatomical, photosynthetic and plant morphological responses,
the production of high quality Petunia × hybrida plants with optimal flowering times could be achieved through the control of both light intensity and light quality. The
appearance of A 1 and A 2 anionic POD isoforms could be also used for successful scheduling under light treatments. 相似文献
2.
Oviposition habitat selection (OHS) is increasingly being recognized as playing a large role in explaining mosquito distributions and community assemblages. Most studies have assessed the role of single factors affecting OHS, while in nature, oviposition patterns are most likely explained by multiple, interacting biotic and abiotic factors. Determining how various factors interact to affect OHS is important for understanding metapopulation and metacommunity dynamics. We investigated the individual and interactive effects of three water salinities (0, 15 and 30 p.p.t. NaCl added) and the aquatic predator Anisops debilis Perplexa (Hemiptera: Notonectidae) on OHS and larval performance of the mosquitoes Ochlerotatus caspius Pallas and Culiseta longiareolata Macquart (Diptera: Culicidae) in outdoor-artificial-pool and laboratory experiments. C. longiareolata inhabited only freshwater pools, strongly avoided pools containing A. debilis, and larvae experienced lower survival in the presence of A. debilis. Salinity concentration interacted strongly with the predator in affecting OHS and larval survival of O. caspius; oviposition increased with increasing salinity in the absence of the predator and decreased with increasing salinity in the presence of the predator. O. caspius larval survival in predator-free pools was lowest in freshwater and highest at intermediate salinity. In predator pools, survival was highest at high salinity, where predation rate was shown to be lowest in the laboratory. Our results highlight that assessing the role of single factors in affecting mosquito distributions can be misleading. Instead, multiple factors may interact to affect oviposition patterns and larval performance. 相似文献
3.
Fuel management techniques are commonly used in shrublands to reduce wildfire risk. However, more information about the ecological
effects of these treatments is needed by managers and ecologists. In an effort to address this need, we performed a replicated
(4 replicates per treatment) 48-ha experiment in northern California chaparral dominated by Adenostoma fasciculatum to determine the effects of two fuel reduction types (prescribed fire and mastication) and three different seasons of treatment
(fall, winter, and spring) on shrub cover, height, and seedling density. Exclosures (2.5 m 2 each) were also used to assess herbivory effects. By the third post-treatment year, prescribed fire treatments had higher
shrub cover (71 ± 2%) than mastication (43 ± 4%). There was no treatment effect on shrub height, species richness, or composition.
Seedling density was initially higher in prescribed fire treatments (31 ± 4 seedlings m −2) than mastication (3 ± 0 seedlings m −2); however, prescribed fire treatments experienced substantial mortality, especially spring burning, resulting in lower densities
3 years after treatments (18 ± 0 seedlings m −2 after fall and winter fire compared to 2 ± 0 seedlings m −2 after spring fire). A. fasciculatum remained the dominant shrub species after the treatments, and Ceanothus cuneatus recruitment was higher in fall burning. Deer herbivory only affected shrub height, especially in masticated units, resulting
in heights of 55 ± 2 cm in unexclosed areas compared to 66 ± 4 cm inside exclosures by the third post-treatment year. Overall,
our findings suggest that fuel treatments play an important role in shrubland community dynamics, at least in the short-term,
with implications for re-treatment frequency, community structure, and wildlife habitat. 相似文献
4.
The objective was to carry out cytotoxicity assays in Vero cells and cytokines analyses in Balb/c mice as safety assessments to evaluate the probiotic mixture (M) Saccharomyces cerevisiae RC016 (Sc) and Lactobacillus rhamnosus RC007 (Lr) for use as feed additive. Vero cells (10 4 cells per well) were exposed to Sc (2·08 × 10 7, 2·08 × 10 6; 2·08 × 10 5 cells per ml), Lr (8·33 × 10 7; 8·33 × 10 6; 8·33 × 10 5 cells per ml) and their M (1 : 1). Sc concentrations did not affect the Vero cells viability; in contrast, they were lower when exposed to Lr ( P ˂ 0·0001). Vero cells showed increasing viability with M decreasing concentrations (91% viability with M2). Control BALB/c mice received only phosphate buffer saline and the others received the M. The IL-10, IL-6 and TNFα concentrations from intestinal fluid were analysed and no significant differences were observed among treatments. The same occurred with the ratio between IL-10/TNF-α. Beneficial effects of probiotics are associated with the regulation of the excessive inflammatory response; it is desirable they can modulate the cytokines production only under pathological conditions. Here, M administration to healthy mice did not induce negative side effects and expands the knowledge about beneficial effects of using probiotic microorganisms in mixture for feed additives development. 相似文献
5.
To accurately quantify airborne Aspergillus fumigatus ( A. fumigatus) spores in rabbit houses, the real-time polymerase chain reaction (real-time PCR) and culture-based counting method (CCM)
were employed to determine the airborne A. fumigatus spore concentrations. The results showed that, of the three rabbit houses (A, B, and C), the average concentrations of airborne
A. fumigatus spores determined by real-time PCR were 3.0 × 10 3, 3.3 × 10 3, and 1.5 × 10 3 spores/m 3 air, respectively, while those determined by CCM were 2.5 × 10 2, 2.8 × 10 2, and 1.1 × 10 2 colony-forming unit/m 3 air (CFU/m 3 air), respectively, i.e., the former concentration was 12–14 times higher than the latter one. Therefore, the conventional
CCM underestimated the concentrations of airborne fungal spores, and it is insufficient to determine the microbial aerosol
concentration and evaluate the health risk only using CCM. 相似文献
6.
A flow injection (FI) method is reported for the determination of l‐ cysteine, based on its enhancement on chemiluminescence (CL) emission of luminol oxidized by sodium persulphate in alkaline solution. The calibration graph was linear over the range 1.0 × 10 –9–5.0 × 10 –7 mol/L ( r2 = 0.9992), with relative standard deviations (RSDs) in the range 1.1–2.3% ( n = 4). The limit of detection (3σ blank) was 5.0 × 10 –10 mol/L with a sample throughput of 120/h. The method was applied to pharmaceuticals and the results obtained were in reasonable agreement with the amount labelled. The proposed method was also applied to cysteine in synthetic amino acid mixtures. Calibration graphs of N‐acetylcysteine and glutathione over the range 1.0–50 × 10 –8 and 0.5–7.5 × 10 –7 mol/L were also established ( r2 = 0.998 and 0.9986) with RSDs in the range 1.0–2.0% ( n = 4), and the limits of detection (3 σ blank) were 5.0 × 10 –9 and 1.0 × 10 –8 mol/L, respectively. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
7.
Considering the rapid transmission of the dengue virus, substantial efforts need to be conducted to ward-off the epidemics of dengue viruses. The control effort is depending on chemical insecticides and had aroused undesirable conflicts of insecticide resistance. Here, we study the entomopathogenic fungus, Metarhizium anisopliae as a promising new biological control agent for vector control. The pathogenicity effects of Metarhizium anisopliae against field and laboratory strains of Aedes albopictus and Aedes aegypti larvae were tested using the larvicidal bioassay technique. The results demonstrate that the treatments using M. anisopliae isolate MET-GRA4 were highly effective and able to kill 100% of both Ae. albopictus and Ae. aegypti mosquito larvae at a conidia concentration of 1 × 10?/ml within 7 days of the treatment period. The fungus displayed high larvicidal activity against laboratory and field strain of Ae. aegypti larvae with LC 50 values (9.6 × 10 3/ml, 1.3 × 10 3/ml) and LC 95 values (1.2 × 10?/ml, 5.5 × 10 5/ml) respectively. For Ae. albopictus, LC 50 values for laboratory and field strains were (1.7 × 10 4/ml, 2.7 × 10 4/ml) and the LC 95 values were (2.1 × 10?/ml, 7.0 × 10 5/ml) respectively. Interestingly, the susceptibility of field strain towards M. anisopliae was higher as compared to the laboratory strain Aedes larvae. In which, the causative agents of all the dead larvae were verified by the virulence of M. anisopliae and caused morphological deformities on larval body. The findings from this study identify this isolate could be an effective potential biocontrol agent for vector mosquitoes in Malaysia. 相似文献
8.
This study examined the physiological effects of joint and separate parasitism and infection by the endoparasitoid Microplitis pallidipes Szépligeti and the nucleopolyhedrovirus (NPV), respectively, on haemolymph 20‐hydroxyecdysone (20‐E) titre in Spodoptera exigua (Hübner) larvae. The results indicated that in parasitized larvae, virus‐infected larvae (5.7 × 10 3 and 5.7 × 10 5 OB/ml) and parasitized larvae infected with virus at 5.7 × 10 5 OB/ml, compared to healthy larvae, the 20‐E all declined during the first 3 days but began to increase from day 4 after treatment, while in jointly parasitized and infected larvae (5.7 × 10 3 OB/ml), the 20‐E declined during the first 4 days but began to increase on day 5 after treatment. Meanwhile, compared to parasitized larvae, the 20‐E declined during the first 4 days but significantly increased on day 5 in jointly parasitized and infected larvae (5.7 × 10 3 OB/ml), while significantly increased during the first 2 days but began to decrease from day 3 after treatment in jointly parasitized and infected larvae (5.7 × 10 5 OB/ml). Finally, in larvae that were both parasitized and virus infected (5.7 × 10 3 OB/ml), compared to just virus‐infected larvae (5.7 × 10 3 OB/ml), the 20‐E was lower on days 3 and 4 but higher on other days after treatment; in larvae that were both parasitized and virus infected (5.7 × 10 5 OB/ml), compared to just virus‐infected larvae (5.7 × 10 5 OB/ml), the 20‐E was significantly higher at the first 2 days but lower from day 3 after treatment. Our results revealed that 2nd instar larval M. pallidipes in host bodies may release 20‐E into the haemolymph of S. exigua larvae and that NPV infection may stimulate S. exigua to release more 20‐E during its third to fourth instar larval moulting. We found that this stimulatory effect was greater with higher virus concentrations. 相似文献
9.
A conspicuous bioluminescence during nighttime was reported in an aquaculture farm in the Cochin estuary due to Gonyaulax spinifera bloom on March 20, 2020. In situ measurements on bioluminescence was carried out during nighttime to quantify the response of G. spinifera to various mechanical stimuli. The bioluminescence intensity (BI) was measured using Glowtracka, an advanced single channel sensor, attached to a Conductivity–Temperature–Depth Profiler. In steady environment, without any external stimuli, the bioluminescence generated due to the movement of fishes and shrimps in the water column was not detected by the sensor. However, stimuli such as a hand splash, oar and swimming movements, and a mixer could generate measurable bioluminescence responses. An abundance of?~?2.7?×?106 cells L?1 of G. spinifera with exceptionally high chlorophyll a of 25 mg m?3 was recorded. The BI in response to hand splash was recorded as high as 1.6?×?1011 photons cm?2 s?1. Similarly, BI of?~?1–6?×?1010 photons cm?2 s?1 with a cumulative bioluminescence of?~?2.51?×?1012 photons cm?2 (for 35 s) was recorded when there is a mixer with a constant force of 494 N/800 rpm min?1. The response of G. spinifera was spontaneous with no time lapse between application of stimuli and the bioluminescence response. Interestingly, in natural environment, application of stimulus for longer time periods (10 min) does not lower the bioluminescence intensity due to the replenishment of water thrusted in by the mixer from surrounding areas. We also demonstrated that the bioluminescence intensity decreases with increase in distance from the source of stimuli (mixer) (av. 1.84?×?1010 photons cm?2 s?1 at 0.2 m to av. 0.05?×?1010 photons cm?2 s?1 at 1 m). The BI was highest in the periphery of the turbulent wake generated by the stimuli (av. 3.1?×?1010 photons cm?2 s?1) compared to the center (av. 1.8?×?1010 photons cm?2 s?1). When the stimuli was applied vertically down, the BI decreased from 0.2 m (0.3?×?1010 photons cm?2 s?1) to 0.5 m (0.10?×?1010 photons cm?2 s?1). Our study demonstrates that the BI of G. spinifera increases with increase in mechanical stimuli and decreases with increase in distance from the stimuli. 相似文献
11.
A medicinal mushroom, Phellinus linteus, was successfully cultivated using a cheese-processing waste, whey, and the optimal bioconversion conditions for the maximum
mycelial growth rate was also estimated through solid-state cultivation experiments. Response surface analysis with a face-centered
design (center point replication = 5) was applied to statistically approximate the simultaneous effects of the three variables,
i.e., substrate concentration (10–30 g lactose l −1), temperature (20–30°C), and pH (4–6), on the mycelial growth rate of P. linteus. The following is a partial cubic model where η is the mycelial growth rate ( K
r
) and x
k
is the corresponding variable term ( k = substrate concentration, temperature, and pH in order): η = −23.8 + 8.67 × 10 −2
x
1 + 1.48 x
2 + 1.77 x
3 + 8.00 × 10 −4
x
1
x
2 + 7.25 × 10 −2
x
1
x
3 + 5.13 × 10 −2
x
2
x
3 −1.28 × 10 −2
x
12 –3.18 × 10 −2
x
22. −2.64 × 10 −1
x
32 −3.28 × 10 −3
x
1
x
2
x
3 + 4.68 × 10 −4
x
12
x
2. The produced response surface model proved to be significant ( r
2 > 0.99, P-value <0.0001, coefficient of variation <5%) to describe the explored space. Temperature was found to be the most significant
factor of dominant effects on the mycelial growth rate, and other variables such as temperature 2, pH, pH 2, and (substrate concentration 2 × temperature) also showed significant effects on the model output. The maximum mycelial growth rate was predicted to be
2.80 mm d −1 at 29.7 g lactose l −1, 26.2°C, and pH 5. Our results proved a good potential of whey to serve as an alternative growth medium for cultivating P. linteus mycelia. This may provide another potential for managing this nutrient-rich waste in a cost-effective way. 相似文献
12.
The effects of fire retardants on the properties of particle boards made from cottonseed hulls were studied. The boards were treated with (1) 70% borax + 30% boric acid (FR(1)); (2) 60% borax + 25% boric acid + 15% ammonium dihydrogen orthophosphate (FR(2)) and were evaluated for duration of flaming, after-glow, charred area, charred length and per cent loss in weight, along with physico-mechanical properties. Fire retardant properties, water resistance and per cent thickness swelling improved, and bending strength decreased, with increase in concentration of fire retardants. Treatment (2) was found to be the better fire retardants since it served the dual purposes of flame and glow retardation. 相似文献
13.
Concentrations of hypophosphite and phosphite oxidizing bacteria were found to be high, relative to bacterial concentrations
growing on phosphate, in sediment and soil during winter and summer seasons from 12 common terrestrial and aquatic sites using
a most probable number method. The percent of total culturable bacterial concentrations that could use these reduced phosphorus
compounds as a sole source of phosphorus were as follows: hypophosphite, 7–100%; phosphite, 10–67%; aminoethylphosphonate,
34–270%. The average MPN/g (±SEM) was as follows: phosphate, 6.19 × 10 6 (±2.40 × 10 6); hypophosphite, 2.61 × 10 6 (±1.35 × 10 6) phosphite, 1.91 × 10 6 (±1.02 × 10 6); aminoethylphosphonate, 3.90 × 10 6 (± 1.95 × 10 6). Relatively high concentrations of reduced phosphorus oxidizing bacteria were found in both pristine sites and sites with
urban and agricultural disturbance. Concentrations of reduced phosphorus oxidizing bacteria in anoxic sediments and soil were
equivalent. Our data indicate that reduced phosphorus oxidizing bacteria are abundant in the environment and provide strong
evidence for the importance of bacterial P oxidation in nature. 相似文献
14.
A real-time polymerase chain reaction approach was used in this study to determine the population of major ruminal bacterial
species ( Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens) in digesta and rumen fluid of swamp buffalo ( Bubalus bubalis). Four rumen-fistulated, male swamp buffalo were randomly assigned according to a 4 × 4 Latin square design to evaluate the
effect of the urea-treated rice straw (roughage source)-to-concentrate ratio on cellulolytic bacterial distribution. Animals
were fed roughage-to-concentrate (R:C) ratios of 100:0, 75:25, 50:50, and 25:75, respectively. At the end of each period,
rumen fluid and digesta were collected at 0 h and 4 h post-morning-feeding. It was found that feeding urea-treated rice straw
solely increased these three cellulolytic bacteria numbers up to 2.65 × 10 9 and 3.54 × 10 9 copies per milliliter for F. succinogenes, 5.10 × 10 7 and 7.40 × 10 7 copies per millilter for R. Flavefaciens, and 4.00 × 10 6 and 6.00 × 10 6 copies per milliliter for R. albus in rumen fluid and digesta, respectively. The distribution of the three cellulolytic bacteria species in digesta were highest
at 3.21 × 10 9, 4.55 × 10 7, and 4.56 × 10 6 copies per milliliter for F. succinogenes, R. flavefaciens, and R. albus, respectively. Moreover, at 4 h post-morning-feeding, the populations of the three cellulolytic bacteria were higher than
found at 0 h post-morning-feeding. It is most notable that F. succinogenes were the highest in population in the rumen of swamp buffalo and cellulolytic bacteria mostly adhered to feed digesta in
the rumen . 相似文献
15.
The online photoreaction of the rose bengal photosensitized luminol–copper (II) chemiluminescence (CL) system was used for the determination of β-nicotinamide adenine dinucleotide (NADH) and ethanol (EtOH) in pharmaceutical formulations combined with a flow injection technique. NADH can significantly enhance the CL emission of the reaction. For EtOH, alcohol dehydrogenase in soluble form was utilized in the presence of nicotinamide adenine dinucleotide resulting in NADH production. The limit of detection (3 σ blank, 𝑛 = 3) of 4.0 × 10 −8 and 2.17 × 10 −5 M, and linear range 1.3 × 10 −7 to 2.5 × 10 −5 M ( R2 = 0.9998, n = 6) and 0.11–2.17 × 10 −3 M ( R2 = 0.9996, n = 6) were obtained for NADH and EtOH respectively. The injection rate was 100 h −1 with a relative standard deviation ( n = 3) of 1.5–4.8% in the range studied for both analytes. The procedure was satisfactorily applied to pharmaceutical formulations with recoveries in the range 91.6 ± 3.0% to 110 ± 2.0% for NADH and 88 ± 3.0% to 95.4 ± 4.0% for EtOH. The results obtained were very consistent and did not differ considerably from the reported approaches at a 95% confidence limit. The possible mechanism of the CL reaction is also explained briefly. 相似文献
16.
The distribution and presence of hygiene indicator and pathogenic micro‐organisms in 375 samples of attieke marketed in Côte d'Ivoire, and their roles in the food poisoning were evaluated. Microbiological analyses were carried out, which included the total viable bacteria, coliforms, Escherichia coli, Staphylococcus aureus, Salmonella, Bacillus spores, fungi and Clostridium perfringens. The results revealed that the viable bacteria counts ranged from 2·2 ± 1·2 × 10 5 to 3·4 ± 1·4 × 10 6 CFU g ?1, while the yeasts and the moulds counts ranged, respectively, from 2·4 ± 0·12 × 10 4 to 9·8 ± 0·4 × 10 5 CFU g ?1 and 1·3 ± 0·7 × 10 1 to 1·7 ± 0·7 × 10 2 CFU g ?1. Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Citrobacter freundi, Enterobacter amnigenus, Citrobacter youngae, Enterobacter aerogenes, Klebsiella pneumoniae, Serratia marcescens, Enterobacter agglomerans and Klebsiella oxytoca were the bacteria isolated, and Rhizopus spp., Mucor spp., Thamnidium spp., Fusarium spp., Moniliella spp. the fungi. Escherichia coli, Clostridium perfringens and Salmonella spp. were not found. The occurrence of some bacteria and fungi illustrate that attieke collected in Côte d'Ivoire markets may act as a reservoir of pathogenic micro‐organisms for human. Significance and Impact of Study This study demonstrates the great need to carry out microbiological tests frequently on attieke and even more the need to apply correct HACCP system during the production. Attieke is especially a well‐known product in West Africa; hence, it is extremely important to ensure an adequate microbiological quality to guarantee consumers health. Overall, the study highlighted the need for effective communication on microbiological food risks, proper instruction and supervision in food‐handling procedures, greater education on food safety risks. 相似文献
17.
A novel flow injection-chemiluminescence (FI–CL) approach is proposed for the assay of pioglitazone hydrochloride (PG-HCl) based on its enhancing influence on the tris(2,2 ′-bipyridyl)ruthenium(II)–silver(III) complex (Ru(bipy) 32+-DPA) CL system in sulfuric acid medium. The possible CL reaction mechanism is discussed with CL and ultraviolet (UV) spectra. The optimum experimental conditions were found as: Ru(bipy) 32+, 5.0 × 10 −5 M; sulfuric acid, 1.0 × 10 −3 M; diperiodatoargentate(III) (DPA), 1.0 × 10 −4 M; potassium hydroxide, 1.0 × 10 −3 M; flow rate 4.0 ml min −1 for each flow stream and sample loop volume, 180 μl. The CL intensity of PG-HCl was linear in the range of 1.0 × 10 −3 to 5.0 mg L −1 ( R2 = 0.9998, n = 10) with limit of detection [LOD, signal-to-noise ratio ( S/N) = 3] of 2.2 × 10 −4 mg L −1, limit of quantification (LOQ, S/N = 10) of 6.7 × 10 −4 mg L −1, relative standard deviation (RSD) of 1.0 to 3.3% and sampling rate of 106 h −1. The methodology was satisfactorily used to quantify PG-HCl in pharmaceutical tablets with recoveries ranging from 93.17 to 102.77 and RSD from 1.9 to 2.8%. 相似文献
18.
This study investigates the exposure of workers to biological particles in a poultry litter burning plant in operation. The
microorganism concentrations were examined at different workplaces during procedures leading to increased emissions. The concentrations
of culturable airborne mesophilic, xerophilic and thermophilic microorganisms in the ambient air were tested inside and outside
of the burning plant using two different methods of measuring. The focus of this study was on the quantitative evaluation
of culturable bacteria as well as the quantitative and qualitative evaluation of gram-negative bacteria, fungi and thermophilic
actinomycetes. The maximum airborne concentrations were found in the delivery hall. Mesophilic bacteria concentrations reached
up to 1.7 × 10 6 CFU/m 3; gram-negative bacteria up to 9.1 × 10 2 CFU/m 3. Fungal propagule concentrations for xerophilic fungi were between 1.2 × 10 3 and 2.9 × 10 4 CFU/m 3 and for mesophilic fungi between 4.4 × 10 2 and 2.9 × 10 4 CFU/m 3. Among fungi, Aspergillus niger, Eurotium herbariorum and Scopulariopsis brevicaulis species were dominant. Thermophilic actinomycetes reached airborne concentrations of 8.7 × 10 4 CFU/m 3, with increased concentrations of the pathogens causing extrinsic allergic alveolitis. The high concentrations of airborne
microorganisms in poultry litter burning plants and the potential hazard of the intake of microorganisms including potential
pathogens require the introduction of consistent measures in both technical areas and personnel management. 相似文献
19.
Based on a seven-year study of pollen production and release in two different natural populations of Cedrus deodara from Garhwal Himalaya, India, we determined that pollen output follows a two-year cycle. Pollen productivity determinations
considered various sources of variability, including the number of pollen strobili per branch, strobili per tree, microsporophylls
per tree and pollen grains per tree. Each of these parameters revealed significant year-to-year and population effects. Microsporangium
dehiscence took from 2.5 to 3.5 days. Maximum dehiscence was observed between 12:00 and 14:00 h, which coincides with diurnal
highest temperature and lowest relative humidity. Annual production of pollen per tree varied from averages of 4.7 × 10 9, 7.2 × 10 9 and 5.1 × 10 9 in years of low production, with alternate high years, producing 12.6 × 10 9, 14.1 × 10 9, 13.3 × 10 9 and 14.0 × 10 9 pollen grains per tree. Annual pollen production in individual trees of C. deodara ranged from 1.4 × 10 9 to 22.3 × 10 9. 相似文献
20.
The cotton whitefly, Bemisia tabaci (Gennadius) B‐biotype, is fed on by a wide variety of generalist predators, but there is little information on these predator–prey interactions, especially under field conditions. In this study, a real‐time polymerase chain reaction (PCR) assay was developed to quantify B. tabaci B‐biotype remains in predator gut. The B. tabaci B‐biotype genomic DNA copy number was referred to the actual amount of BT1 isolate, the B. tabaci B‐biotype specific DNA fragment. The numbers of BT1 isolate in one B. tabaci B‐biotype egg, individual adult and a single red‐eyed nymph were 2.56 × 10 3, 2.56 × 10 4, and 1.29 × 10 4 copies, respectively. When Propylaea japonica adults fed on one, two, four, eight or 16 red‐eyed nymphs, the detected numbers of BT1 isolate ranged from 2.77 × 10 4 to 4.05 × 10 5 copies, forming a strong linear relationship ( R2 = 0.9899). Following the consumption of two red‐eyed nymphs, prey DNA was detectable in 100% of P. japonica at t = 0, decreasing to 80.0% and 60.0% after 1–4 h and 8 h of digestion, respectively, with 3.36 × 10 4–1.25 × 10 3 BT1 isolate copies. The predation by field‐collected predators, 26 larvae of P. japonica, and of Harmonia axyridis each, Chrysopa spp. larvae ( Chrysopa pallens and C. formosa, 18 individuals in total), and a single adult of Scymnus hoffmanni, 19 adults of Orius sauteri and nine adult spiders ( Erigonnidium graminicolum and Neoscona doenitzi), on B. tabaci B‐biotype were quantified. Of the 99 analysed predator individuals, 3.65 × 10 2–4.60 × 10 5 copies of BT1 isolate, equivalent to 0.8–18.8 red‐eyed nymphs were detected. These results suggest that TaqMan real‐time PCR technology may provide a rapid and sensitive method for quantifying B. tabaci B‐biotype remains in predator guts and will be invaluable in assessing the food web relationship between prey and arthropod predators. 相似文献
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