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1.
Concentration and molecular weight distribution of dissolved organic carbon in a mangrove creek in the Hinchinbrook area,Australia 总被引：1，自引：0，他引：1
The concentration and molecular weight distribution of dissolved organic carbon (DOC) are reported for a mangrove creek in the Hinchinbrook area, Australia. DOC concentration ranged from 1.0mg Cl–1 near the creek mouth to 2.2mg Cl–1 at the innermost part of the creek. There was no apparent spatial trend in molecular weight distribution of DOC, with a >300gmol–1 fraction accounting for about 70% of the total in all samples. DOC concentration fluctuated between 0.5 and 1.2mg Cl–1 over one tidal cycle. The samples collected at low tide and during the rising tide were dominated by DOC of >300gmol–1 and <300gmol–1, respectively. This suggested the export of high molecular weight DOC, probably originating from litter leachates, and the import of low molecular weight DOC to the creek. 相似文献
2.
3.
In vitro flowering of green and albino Dendrocalamus latiflorus 总被引：1，自引：0，他引：1
To propagate Dendrocalamus latiflorus, we used in vivo inflorescences to produce calli on Murashige and Skoog basal (MS) medium supplemented with 3 mg/l 2,4-dichlorophenoxyacetic
acid (2,4-D), 2 mg/l kinetin, 250 mg/l polyvinyl pyrrolidone (PVP), and 1% coconut milk. Multiple shoots were generated on
MS medium supplemented with 0.1 mg/l thidiazuron (TDZ). The green plantlets were successfully transferred to soil. Multiple
albino shoots also regenerated and were able to proliferate on medium containing cytokinins, especially TDZ. Albino multiple
shoots rooted in medium containing α-naphthaleneacetic acid (NAA), and callus formation was observed in the presence of 2,4-D
and picloram. Green and albino regenerates flowered after 8 months of subculture. The flowering ratio increased to 44% after
three treatments in medium containing 1 mg/l TDZ. Morphological observations revealed that the in vitro green and albino flower
organs were normal. However, pollen derived from the in vitro flowers of both the green and albino plants were sterile. 相似文献
4.
1983—1987年对湖北省武昌、宜昌、当阳县和陕西省城固县油橄榄中试园土壤与营养状况进行了研究。结果表明:油橄榄生长较好的(一类树下)土壤条件是pH7—8,CaCO_3>5％,有机质>1.8％,速效N>74.4—87.4mg/kg土,速效P>40mg/kg土,速效K>200mg/kg土,交换性Ca103—181mmol/kg土,交换性Mg24—34mmol/kg土。生长结实好的一类树叶片营养指标为N2.0—2.5％,P_2O_5 0.14％,K_2O 1.5％,CaO 4.0％,MgO 0.8％。通过分析建立了预测产量和施肥控制的回归方程。 相似文献
5.
Acetylation of wood was carried out in acetic anhydride only, acetic anhydride/xylene 1:1 (v/v), and acetic anhydride/pyridine 4:1 (v/v) solutions. The antishrink efficiency (ASE), hygroscopic properties, vibrational properties, and bending strength were compared among the three reaction solutions. The ASE was a simple function of weight gain (WG); the equilibrium moisture content at a given WG differed among the reaction solutions. Based on this fact and the results of repeated water soaking and oven-drying tests, it was found that the bulking effect was a major factor, and that decreased hygroscopicity contributes only slightly to the dimensional stabilization by acetylation. The difference in equilibrium moisture content among reaction solutions appears more significant in block samples than wood meal, probably due to the fiber-to-fiber bonds in the former. The tendencies for change in the specific Youngs modulus and the loss tangent differed among reaction solutions, whereas in the static bending test the difference was not marked.Part of this report was represented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002 相似文献
6.
《Journal of Sustainable Forestry》2013,32(2-3):103-114
Abstract Micropropagation protocols for Dendrocalamus asper using nodal shoots and seeds culture are described. Multiple shoots were induced through forced axillary branching. Ninety-five percent of the nodal shoot explants taken from juvenile primary and lateral branches, produced multiple shoots through axillary buds activation within 2 to 8 weeks on Murashige & Skoog's (MS) medium supplemented with 0.1-15 mg/l benzyladenine (BA). The cultured seeds also produced multiple shoots (1-20) within 6 weeks on this medium. The multiple shoot differentiation was influenced by the concentration of BA in the medium. The in vitro generated shoots were excised and subculture on MS + 3.0 mg/l BAP for further shoot multiplication. Fifteen to 20 fold rate of shoot multiplication was achieved by regular subculturing. These shoots were multiplied for more than 3 years without loss of vigor. Ninety-five percent of the shoots were rooted, when propagules (each consisting of cluster of 3 shoots) were transferred on to MS medium with 3.0 mg/l NAA or 10 mg/l indole-3-butyric acid (IBA). To date, 18,000 plants (through axillary bud initiated from nodal ex-plants) and 6,000 plants from seed culture have been hardened and acclimatized. 12,000 plants have been field transferred. 相似文献
7.
Chemical and physical changes required for producing dimensionally stable wood-based composites 总被引：5，自引：1，他引：5
Dr. W. E. Hsu Dr. W. Schwald Mrs. J. Schwald Mr. J. A. Shields 《Wood Science and Technology》1988,22(3):281-289
Summary The springback of compressed wood caused by built-up internal stresses results in excessive thickness swelling of wood-based composites when exposed to moisture. Steam pretreatment can cause partial hydrolysis of hemicellulose for both hardwoods and softwoods which markedly increases the compressibility of wood and in turn significantly reduces the build-up of internal stresses in composites during hot pressing. This steam pretreatment process is a very effective method for producing dimensionally stable wood-based composites. Mild steam pretreatments (e.g. 3 to 4 min at 1.55 MPa) cause a significant reduction of the water insoluble xylan content in hardwoods and the amount of xylan, mannan and galactan in softwoods without any apparent changes in the cellulose or lignin content.The authors wish to thank G. Bastien and B. S. Lethbridge for technical assistance. W. Schwald is grateful to the Fonds zur Förderung der wissenschaftlichen Forschung, Vienna, Austria for granting an Erwin-Schrödinger scholarship (Proj. No. J0128C) 相似文献
8.
采用螯合树脂对废水中的钴锰铁镍等重金属离子进行了吸附分离,验证了树脂处理重金属废水的资源化工艺可行性,结果表明:通过树脂的吸附—再生—富集工艺过程可以将回收的钴锰浓度分别从8mg/L、4mg/L提浓至11000mg/L、4900mg/L以上,铁镍的杂质含量在0.5‰以下。研究了树脂吸附再生出水的颜色变化与水质数据的规律性和工艺操作条件,提出了可采用颜色变化对树脂吸附再生过程的参数加以调整,以供参考。 相似文献
9.
Data from a trial of 36 families at Little Wittenham, North Oxford was used to assess growth traits and stem form in common
ash (Fraxinus excelsior, L.). The trial followed a design described by Barnes (Silv Genet 44(2–3):81–88, 1995) as the Breeding Seedling Orchard (BSO).
The objectives of the study were to determine variation in growth and form traits and estimate genetic parameters of families.
Assessments conducted at 3–8 years for height, diameter at breast height (dbh), straightness and forking showed significant
differences (P < 0.05) among families with Guys (19), Settrington (34), Overbury (23) and Grimthorpe (36) being the best performers while
Coleford (3 and 5) Gwynedd (27) and Bacheiddon (32) were the least performers. At the overall level, the additive genetic
coefficient of variation (CVA) ranged between 10.2 and 12.7% for height and 1.5 and 2.1% for dbh. Height had a high genetic correlation (rg = 0.85) with dbh whilst forking had low correlation (rg = 0.25) with height. Estimates of heritability decreased with age from
= 0.62 at 3 years to = 0.30 at 8 years for height while values for dbh decreased from = 0.48 at 4 years to = 0.27 at 8 years. Some genetic gains are possible despite the low genetic variation among families; height had the greatest
potential of genetic gain (12.5% at 8 years). Results suggest that early selection of superior families of Fraxinus excelsior appears to be feasible and it could be possible to achieve simultaneous improvement in both growth and form. 相似文献
10.
Prunus africana, from the moist highlands of sub-Saharan Africa, is subject to great exploitation because its bark is used in the treatment of prostate-related diseases. A better understanding of the biology of its seed could help the ex situ and in situ conservation of the species. Fifty per cent of fresh seeds (46.8% MC) from mature purple fruits harvested in Kenya germinated after 10 days incubation at 25°C. The germination rate was linearly related to constant temperature, giving a prediction for the minimum temperature for germination at ca. 0.6°C. All seeds germinated at 5°C during 4 months fully hydrated storage. P. africana seed is, thus, neither dormant nor chilling sensitive. The relationship between equilibrium moisture content and relative humidity was used to construct a sorption isotherm, against which seed desiccation and storage responses were assessed. Seventy six per cent of mature seeds survived drying to 4.5% MC (22% RH) compared to 17% of seeds from immature purple-green fruits. Although, 25–45% of mature seeds survived at 8–12% MC after 2 months, only 10% remained viable after 6-month storage at 5°C. This study proposes optimum conditions for the artificial regeneration of P. africana seeds and highlights the need for further experiments storing dry seeds at sub-zero temperatures. 相似文献
11.
《Fitoterapia》1999,70(1):44-49
The chemical composition of the largely used tea from lemon verbena, Aloysia triphylla, was investigated. The qualitative and quantitative composition of the main aromatic and polyphenolic constituents of tea made by infusion from leaves were examined. The results showed that the relative proportions of the active constituents differ from those of the original leaves. The tea contained a large amount of polyphenolic compounds (mean value 675 mg/l; extraction yield 65%) including verbascoside (400 mg/l) and luteolin 7-diglucuronide (100 mg/l). It contained also 42 mg/l of essential oil (extraction yield 51%) with much more citral (77% of the essential oil) than the original leaves (41%). 相似文献
12.
The effect of plantation spacings (types A-E) on the bending strength and dynamic modulus of elasticity of 41-year-old Taiwan-grown cedar (Cryptomeria japonica D. Don) was investigated. The results indicate that the highest values for the static bending modulus of elasticity (MOE), modulus of rupture (MOR), and dynamic modulus of elasticity (ED, E
Dt) occurred in trees obtained from those most densely planted (type A); there was a significant difference between type A and the other four spacing types (B, C, D, and E), but there were no significant differences among those four types. Interrelations among MOE, MOR, E
D, and E
Dt could be represented by positive linear regression formulas, which revealed highly significant differences. The relations among the square value of stress-wave transmission velocity (Vt
2 and Vt
2) and MOE, MOR, E
Dl, and E
Dt, respectively, could be represented by positive linear regression formulas. The differences were highly significant.Part of this report was presented at the International Wood Engineering Conference '96, New Orleans, LA, USA, October 1996 相似文献
13.
We conducted field and pot experiments to investigate the effects of brassinolide on 1-year-old Robinia pseudoacacia L. seedlings. In the field experiment, seedling roots were soaked in brassinolide solutions containing 0–0.4 mg/l pure brassinolide
before planting. Survival and growth of the seedlings were determined 8 months later. The results showed that soaking roots
in brassinolide prior to planting significantly increased the survival and growth of seedlings. The best results were in the
0.2 mg/l brassinolide treatment. In the pot experiment, roots were soaked in 0–0.4 mg/l brassinolide before planting followed
by a foliar application of brassinolide when the seedlings leafed out. After the seedlings were established, the soil water
content in the pots was regulated to simulate drought conditions and various physiological parameters were measured. The results
showed that treatment with 0.2 mg/l brassinolide decreased the transpiration rate, stomatal conductance and malondialdehyde
(MDA) content of seedlings growing under moderate or severe water stress compared to untreated seedlings. Leaf water content,
predawn water potential, soluble sugar content, free proline content, and superoxide dismutase (SOD), peroxidase (POD) and
catalase (CAT) activities were all greater in water-stressed seedlings in the 0.2 mg/l brassinolide treatment compared to
the control. The results indicate that the application of brassinolide can ameliorate the effects of water stress and enhance
drought resistance of Robinia seedlings. Treatment of seedlings with brassinolide may be a useful management tool for afforestation projects in arid and
semiarid areas. 相似文献
14.
Spatial variations of groundwater salinity in a mangrove-salt flat system,Cocoa Creek,Australia 总被引：2，自引：0，他引：2
In this work the average groundwater salt concentration in a mangrove swamp and tropical salt flat system adjacent to Cocoa Creek near Townsville in North Queensland was measured with ground conductivity probes based on low frequency EMI (Electromagnetic Induction) and V-I (Resistivity) Methods. Transects of conductivity were measured with the conductivity probes and the spatial variations in the average groundwater salt concentration were determined from conductivity measurement with both probes. Lower concentrations occurred within mangrove forest as well as near the edges of the salt flats. Comparison of the results above 0.8 m and below 0.8 m showed that as depth increases, the concentrations become more homogeneous. For example at 0.4 m, salt concentrations across the salt flat vary from 75 g/l to 175 g/l where at 2 m the variation is only from about 75 g/l to 125 g/l. High lateral groundwater salt concentration gradients occured at the boundary between the mangroves and salt flat and also at the edges of the salt flat. Typical gradients were about 6 g/l/m and 2 g/l/m respectively. 相似文献
15.
Adult trees of Pinus armandii var. amamiana (PAAm) and P. thunbergii grown in the field were inoculated with 100000 or 1000 of the nematode Bursaphelenchus xylophilus to evaluate their susceptibility to pine wilt disease. PAAm trees inoculated with 100000 nematodes started to show disease symptoms 2 weeks after inoculation, and all died within 29 weeks. Although the PAAm trees inoculated with 1000 nematodes tended to show delayed disease symptoms compared with those inoculated with 100000 nematodes, all of them died within 33 weeks after inoculation. All P. thunbergii trees inoculated with 1000 nematodes had died 6 weeks after inoculation. In the nematode-inoculated PAAm trees, death of branches distal to the nematode inoculation site was the first visible symptom, followed by the systemic discoloration of needles, whereas the whole tree wilted simultaneously in P. thunbergii trees. In nematode-inoculated PAAm trees, the period from inoculation to death was longer than that in P. thunbergii. These results suggest that adult PAAm trees are susceptible to pine wilt disease, but are less vulnerable than P. thunbergii. 相似文献
16.
G. Saour 《Journal of pest science》2008,81(1):3-8
The effect of the chloronicotinyl insecticide (thiacloprid 480 SC) was evaluated to determine its potential in controlling
the potato tuber moth, Phthorimaea operculella. Application of thiacloprid at various concentrations (0.1–0.4 ml/l) on different age groups of eggs (1–4.5 day-old) had
no effect on egg hatchability. However, slight embryocidal effect was noted in all egg age groups exposed to 0.4 ml/l concentration.
Egg incubation period was increased (20%) when 4–4.5 day-old eggs were treated with thiacloprid at a rate of 0.4 ml/l compared
with the untreated control. Thiacloprid was effective in reducing larval survival on potato seedlings or adults emergence
from potatoes, exhibiting activity for at least 14 days after application. When already infected potato seedlings or tubers
were treated with thiacloprid at a rate of 0.4 ml/l, adult emergence was decreased. Larvae that hatched from thiacloprid-treated
eggs and fed, untreated tubers, encountered some difficulties in surviving and emerging as adults. Our data suggest that potato
plants or tubers treated with thiacloprid at a commonly used rate (0.4 ml/l) should be well protected from the possibility
of infestations by the potato tuber moth.
Publication of this article was held up owing to technical problems. The publisher apologizes sincerely for this lengthy delay. 相似文献
17.
Preliminary antinociceptive, antioxidant and cytotoxic activities of Leucas aspera root 总被引：1，自引：0，他引：1
The ethanolic extract of Leucas aspera root was subjected to acetic acid induced writhing inhibition, 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging assay and brine shrimp lethality bioassay for screening of antinociceptive, antioxidant and cytotoxic activity, respectively. The extract produced significant writhing inhibition in acetic acid induced writhing in mice at the doses of 250 and 500 mg/kg. The extract showed a significant free radical scavenging activity with an IC(50) of 8 microg/ml. The extract showed significant lethality to brine shrimp with an LC(50) value. 相似文献
18.
Two types of baited pitfall traps with standardized food attractants (alpha-pinene, 96% ethanol and water) were compared in monitoringHylobius abietis (L.) populations at several localities in southern Bohemia (Czech Republic). The smaller type (volume 1 l)) proved less useful in comparison with the larger type (volume 15 l). The latter type is described and discussed in more detail with respect to its application in the field.
With 2 figures 相似文献
Zusammenfassung Zwei Typen von Bodenfallen, beködert mit standardisiertem Fraßlockstoff (-Pinen; 96% Äthanol; Wasser) wurden zur Überwachung vonH. abietis an verschiedenen Standorten im südlichen Böhmen (C R) verglichen. Der kleinere Typ (Volumen 1 l) erwies sich als weniger gut geeignet als der größere Typ (Volumen 15 l). Letzterer wird ausführlich beschrieben und hinsichtlich seiner Anwendung im Freiland erörtert.
With 2 figures 相似文献
19.
In vitro regeneration of complete plants from nodal single-bud segments of 2-year-old Australian Cedar (Toona ciliata) trees were obtained under defined nutritional and environmental conditions. Explants were dissected from plants obtained by germination of seeds and growth in pots in a greenhouse. The best medium for shoot regeneration was that of Murashige and Skoog at 1/4 strength with 3% sucrose (1/4 MS), supplemented with 0.1 mg/l IBA and 0.5 mg/l BAP. Rooting of regenerated shoots was observed in MS medium with 0.1 mg/l IBA. Using mature tree material was more difficult. Forced flushing was used to induce shoot development on branches of a 10-year-old tree. Nodal segments of these epicormic shoots formed shoots in vitro on 1/4 MS + 0.01 mg/l IBA + 5 mg/l BAP, but rooting was never observed. 相似文献
20.
Three superior clones of Eucalyptus grandis hybrids were micropropagated through several steps. Five-year-old trees were girdled to induce juvenile sprouts. Cultures were attempted from mature branches and sprouts. Branches from mature trees were 100% contaminated while sprouts were only 40% contaminated. Pre-initiation hormone free medium and dark environment were used to screen for contaminants and to reduce production of phenolic compounds. Initiation of auxillary buds was achieved with modified MS plus 0.05 mg/l NAA and 0.5 mg/l BAR High multiplication rates were obtained on auxin-free medium with 0.6 mg/1 BAR Elongation of shoots was best on media with high auxin (2.5 mg/l of IBA) and cytokinin (1–1.5 mg/l of zeatin). Continual subculture on the multiplication medium improved rooting significantly. Up to 98% rooting was achieved on 1/4 MS with 2 mg/l IBA. Rooted propagules were successfully transferred to a mist greenhouse with 82% survival, and then to greenhouse conditions. 相似文献