Susceptibility of species of Juglans to pathovars of Xanthomonas campestris

Bacterial blight is considered one of the most serious diseases affecting the genus Juglans. Artificial inoculations with Xanthomonas campestris pv. Juglandis were performed in the field by spraying seedlings of Juglans cinerea, Juglans hindsii, Juglans mandshurica, Juglans nigra, Juglans regia and Juglans sieboldiana. Juglans nigra, J. cinerea ana J. sieboldiana proved to be the most resistant. The multiplication ability of Xanthomonas campestris pv. corylina, X. c. pv. juglandis, and X. c. pv. campestris was evaluated by injecting 2-year-old seedling leaves of J. mandshurica, J. nigra and J. regia. The bacterial growth was monitored in the infected tissue over 12 days. Xanthomonas c. pv. juglandis exhibited a high growth rate and induced black greasy spots in J. mandshurica and J. regia; X. c. pv. campestris grew in leaf tissues without inducing symptoms, X. c. pv. corylina showed a very low growth rate. None of the tested bacterial strains multiplied in the leaves of J. nigra. This confirms the results obtained in the field tests. Juglans regia was the most susceptible among the walnut species tested.     

Measurement of the dynamic modulus of elasticity of wood panels

This study investigated the dynamic modulus of elasticity (DMOE) of wood panels of Fraxinus mandshurica, Pinus koraiensis, and Juglans mandshurica using the natural frequency measurement system of fast Fourier transform (FFT). The results were compared with the static modulus of elasticity (E _S) tested by a mechanical test machine. The results show a significant correlation between E _S, transverse vibration DMOE (E _F), and longitudinal vibration DMOE (E _L). For all of these species, the correlation between E _S, E _F and E _L is more significant than the individual species, which indicated that the FFT method is universal. The correlations between E _S and sample’s density (ρ) are significant, but the correlation coefficient of E _S and ρ is lower than those between E _F, E _L and E _S. The E _S of wood is more accurately tested by the analysis based on FFT measurement than by the estimation based on density. __________ Translated from Scientia Silvae Sinicae, 2005, 41(6): 126–131 [译自: 林业科学, 2005, 41(6): 126–131]     

Nondestructive test and prediction of modulus of elasticity of veneer-overlaid particleboard composite

The effects of grain angle, thickness of face veneer, and shelling ratio on dynamic modulus of elasticity (E) of veneer-overlaid particleboard composite (VOP) were examined by using nondestructive test. In this study, the possibility that E of VOP can be predicted by means of some empirical formula was also discussed. This study has shown that grain angle, thickness of face veneer, and shelling ratio have substantial effects on E of VOP. The E at 0° of grain angle of face veneer was the largest, decreasing rapidly with increase in the grain angle. The lowest value of E occurred at 90° of grain angle of face veneer. The relationship between grain angle of face veneer and E of VOP can be expressed in the form of Jenkin’s and Hankinson’s equations. The orthotropic properties of wood and VOP defined as the ratio E ₀/ E ₉₀ were 25.7 for wood and 4.7 for VOP. When the grain direction of face veneer was parallel to the length of the specimens, the E of VOP increased with increasing shelling ratio. VOP increased E from 125 to 179% over that of the particleboard and veneer thickness from 2.1 upto 3.6 mm. However, when the grain direction of face veneer was perpendicular to the length of the specimens, the E of VOP decreased with increasing shelling ratio. VOP decreased E from 23 to 41% over that of the particleboard and veneer thickness from 2.1 upto 3.6 mm. The relationship between E of VOP and face veneer thickness can be expressed in the form of a second-order parabolic equation. Rule of Mixture (ROM) can be used to predict E of VOP from the E of wood element and particleboard element.     

Theory of the shrinkage of wood

Summary The wood, composed of alternate earlywood and latewood lamellae, forms a statically indeterminate system with two redundants. The redundant forces are the shearing forces arising at the edge of the boundary between earlywood and latewood in the longitudinal and in the tangential directions of wood. By determining the redundant forces according to the theory of statically indeterminate systems, we know the state of stress and the state of detormation of the wood element and thus can determine its shrinkage and stresses in the longitudinal, tangential and radial directions.

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Zusammenfassung Holz ist aus Früh-und Spätholzlamellen aufgebaut und bildet damit ein statisch unbestimmtes System mit zwei statisch unbestimmten Größen. Diese statisch unbestimmten Größen sind die Scherkräfte, die in longitudinaler und tangentialer Richtung an den Kanten der Grenzschicht zwischen Früh-und Spätholz entstehen. Bestimmt man die statisch unbestimmten größen nach der Theorie der statisch unbestimmten Systeme, so kennt man den Spannungs-und Verformungszustand der Gefügeteile des Holzes und ist damit in der Lage, scine Schwindung und Schwindspannungen in longitudinaler, tangentialer und radialer Richtung zu berechnen.

     

Characterization of strength properties of branchwood and stemwood of some tropical hardwood species

The mechanical strength properties of the branchwood of Aningeria robusta and Terminalia ivorensis with diameters ranging from 10 to 25 cm were examined to determine the suitability of branchwood as raw material for downstream processing. The study precisely assessed the static bending strengths, compression strengths and shear strengths parallel to the grain of the branchwood and stemwood of T. ivorensis and A. robusta. It was observed that under static bending, the overall (sapwood and heartwood combined) modulus of rupture and modulus of elasticity of the branchwood of A. robusta and T. ivorensis were lower than that of their corresponding stemwood. The results further show that the overall compression and shear strengths parallel to the grain of the branchwood of A. robusta and T. ivorensis were higher than that of their corresponding stemwood. Under static bending, compression parallel to the grain, and shear parallel to the grain, the experimental results indicate that the sapwood of the branchwood from both T. ivorensis and A. robusta had lower strength values than that of their corresponding heartwood. Similar results were recorded for the stemwood of T. ivorensis where the heartwood had higher strength values than the sapwood. However, in the case of the stemwood of A. robusta, the sapwood had higher strength values than the corresponding heartwood.     

Inhibition of Armillaria by bacteria isolated from soils of the Boreal Mixedwood Forest of Ontario

Pseudomonas fluorescens, Pseudomonas spp., Bacillus spp., Enterobacter spp., Serratia spp. and Agrobacterium radiobacter were isolated from root-free soils of the Boreal Mixedwood Forest of Ontario a, nd found to be capable of inhibiting the linear growth of Armillaria ostoyae in vitro. Isolates of P. fluorescens, Bacillus spp. and A. radiobacter were the most effective inhibitors of mycelial growth. To test the ability of the bacteria to suppress rhizomorph formation, A. gallica, which produces rhizomorphs in culture more consistently than does A. ostoyae, was used; only a small fraction of P. fluorescens and Bacillus spp. isolates were capable of preventing in vitro rhizomorph formation by A. gallica.     

落叶松水浸液对胡桃楸幼苗生长的影响

A study was conducted to detect the effect of water extracts from different parts such as root, bark, branch and leaf, of adult larch, Larix gmelini, trees on growth of Manchurian walnut, Juglans mandshudca, seedlings and the allelopathy between the two tree species. Four concentrations （100 g. kg i, 50 g. kg^-1, 25 g. kg^-1 and 12.5 g. kg^-1） were prepared for each kind of extracts. Result showed that the water extracts with low and moderate concentrations accelerated the growth of collar diameter and increased biomass and root/shoot ratio of walnut seedlings. The water extracts from branches and barks with low and moderate concentrations accelerated the height growth of the seedlings, while those from leaves and roots slightly decreased the height growth of seedlings. The fact that application of water extracts of larch improved the growth of Manchurian walnut attributes possibly to the allelopathy between the two tree species.     

Relative efficacy of strobilurin formulations in the control of downy mildew of sunflower

The efficacy of three commercial formulations of strobilurins, viz., trifloxystrobin, kresoxim-methyl, and azoxystrobin was evaluated against sunflower downy mildew disease caused by Plasmopara halstedii under laboratory, greenhouse, and field conditions. Complete inhibition of sporangial sporulation, zoospore release, and motility was observed with 2 μg ml⁻¹ in trifloxystrobin, and 5 μg ml⁻¹ for azoxystrobin and kresoxim-methyl. Seed treatment with different concentrations of strobilurins enhanced seed germination and seedling vigor of sunflower to varying degrees compared to control. Highest seed germination was recorded at 10 μg ml⁻¹ in kresoxim-methyl, and maximum seedling vigor was noticed with trifloxystrobin at 30 μg ml⁻¹. The effect of strobilurins was tested as seed treatment, foliar application, and seed treatment followed by foliar application. Under greenhouse conditions none of the concentrations used, either as seed treatment and foliar application, were phytotoxic. For the three strobilurins, the seed treatment along with foliar application enhanced the protection of the plants as compared to only the treatment of seeds. Foliar spray treatments alone provided an intermediate control of the disease. Trifloxystrobin showed a better effect than kresoxim-methyl and azoxystrobin. Disease curative activity of trifloxystrobin was higher compared to kresoxim-methyl and azoxystrobin. Tested fungicides when applied on adaxial leaf surface showed partial translaminar activity, and disease inhibition was marginal. Loss of trifloxystrobin and azoxystrobin activity over time was low, indicating stable rainfastness residual activity. A trend in protection against downy mildew disease similar to greenhouse results was evident in the field trials. This is the first report of strobilurins exhibiting high activity against P. halstedii and is a promising fungicide for controlling sunflower downy mildew disease by seed treatment and foliar spray.     

晚松悬浮细胞系的建立和原生质体的分离

植物悬浮细胞系的建立和原生质体的分离已被广泛地应用于生理学、生物化学、细胞学、遗传学及分子生物学的研究 ,它是生物技术中进行原生质体培养、杂交、基因转移、突变系筛选等项研究的较理想手段[1] 。针叶树在这方面的研究起步虽晚 ,但至今已取得令人瞩目的进展[2 ] 。晚松     

THE BEHAVIOR OF ADULT OF OSIER WEEVIL

THEACTIONLAWoFADULTThcadultsofOsierweevilwereobservedonafixedspotinfieldandraisedindoorsandinfieldseparatelyinl987-9o.Theboxes(4()x4()x6ocm)ineachofWhichl5pairsofadultswereplacedwereusedwiththrcere-peats.Thesamesizesofboxesinwhichtl1eadultsxvcrcraisedx`eredesignedindoorswithtWorepeats.l5canswerealsousedineachofwhlchapairofadultwasplaced.ThefreshbranchesofPoplarthattheadultswcrelikctoeatt`crereplacedilladayabout.ThcEmcrgcnccLawofAdultOsierwecvilstartcdemergenceinthclasttendaysofJuly.…     

Effects of flooding on growth of seedlings of woody riparian species

The effects of flooding on growth of seedlings were compared over a 7-month period (April–November) among six different woody species: Aesculus turbinata, Cercidiphyllum japonicum, Fraxinus platypoda, Pterocarya rhoifolia, Pterostyrax hispida, and Quercus mongolica var. grosseserrata. Flooding reduced the shoot length of F. platypoda, P. rhoifolia, C. japonicum, P. hispida, and Q. mongolica var. grosseserrata seedlings but did not affect that of A. turbinata seedlings. Among control seedlings, shoot elongation occurred once in A. turbinata and twice in F. platypoda and Q. mongolica var. grosseserrata; the other species continued to grow from April to August. Among the flooded plants of all species, shoot elongation occurred only once at the beginning of the growing season. On August 25, flooding significantly reduced the number of developed leaves as compared with control plants except for A. turbinata. In the flooded plants except for F. platypoda, leaf fall began on June 30; in controls, by contrast, the number of developed leaves increased until August 25. Flooding reduced the total dry weight increment in all species. The survival ratio of flooded plants after the experiment differed with species. All of the F. platypoda and A. turbinata seedlings survived the flooding treatment, while only 20% of P. hispida and 30% of Q. mongolica var. grosseserrata survived. Flooding seriously affected the growth of riparian pioneer species including P. rhoifolia, C. japonicum, P. hispida, and Q. mongolica var. grosseserrata. The effects of flooding on growth of the seedlings differed with the tree species because of differences in leaf-emergence pattern and physiological flood tolerance. The responses of tree seedlings to flooding reflected species habitats and growth patterns.     

CONTROL TECHNIQUE OF BACTERIAL CANKER OF POPLAR

The poplar bacterial canker caused by Erwinia sp is a serious disease spreading inmost parts of Northeast China,where poplars are cultivalted.The disease seriously infects thosepoplars belonging to section Aigeiros or the intersection hybrids of section Tacamahaca and section Aigeiros and their clones.Five fine poplar cultivars resistant to the bacterial canker have been ob-tained by screening tests.They are Lz_2(Populus simonii×nigra var.italica),A_(15)(P.×sp.)613(P.×sp.),A_(102)and A_(98)(P.simonii×sp.)T following chemicals are obviously effective,such as:50％DT germicide ,40％ XF-136 and 10％ C.C.M.A.or 12.5％ ramphencol and 50,000 ppm/mlvalidamycin,with which the stems or roots can be watered.     

Diversity and bioactivity of bacterial endophyte community of Cupressaceae

The plant family Cupressaceae (Coniferales) harbours diverse endophytic fungi with antifungal, antibacterial and antiproliferative activities. Here, endophytic association of a broad bacterial community with the healthy foliar tissues of Cupressus arizonica, Cupressus sempervirens, Juniperus communis and Thuja orientalis (Cupressaceae) is shown. We isolated over 69 endophytic bacterial strains of Proteobacteria, Bacilli and Actinobacteria from Cupressaceae. The initial screening for antifungal activity against Pyricularia oryzae identified eleven superior bacterial strains which were identified as Brevundimonas diminuta CAE₂₄ (G^?, Caulobacteraceae, Alphaproteobacteria); Stenotrophomonas maltophilia CAE₂₃, CSE₄, CSE₁₂, CSE₄₂, CSE₄₉ and CSE₆₂ (G^?, Xanthomonadaceae, Gammaproteobacteria); Bacillus pumilus CSE₆₆ and Bacillus subtilis POE₂₆ (G⁺, Bacillaceae, Bacilli); and Microbacterium resistens CSE₁₉ (G⁺, Microbacteriaceae, Actinobacteria). The dominant isolated bacterial species was S. maltophilia. This species represented 63.6% of the superior strains which was ubiquitous and also non‐host specific. In addition, the superior bacterial strains produced bioactive secondary metabolites and volatile compounds (VOCs) with antifungal activity against the fungal pathogens of Cupressaceae, that is Diplodia seriata, Phaeobotryon cupressi and Spencermartinsia viticola. The antagonistic activity of the endophytic bacteria on the target fungi was also confirmed in vitro. To our knowledge, this is the first to document such an endophytic bacterial community in Cupressaceae and its bioactivity. These findings may find application in organic agroforestry for plant disease biocontrol and in biopharmacy for lead molecule discovery.     

细叶桉种源-家系综合选择的研究

对细叶桉14个种源的100个家系生长性状,形质性状进行源间和家系间的差异分析和遗传分析,结果表明性状间差异极显,家系遗传力大于单株遗传力,除分枝性状外,生长性状与形质性状相关极显。7年生生长最好的13659种源的平均树高,胸径和单株材积分别是最差种源13308的1．27,1．32和2．14倍,7年生最优家系是No.17号家系,其单株材积达0.06134 m^3,是最差家系No.33号的3．6倍,虽家系群体均值的1．74倍。运用指数选择法对家系进行多性状综合选择,初步选出22个优良家系,其树高,胸径,材积,枝下高,干形和分枝的遗传增益分别达到7．31％,6．39％,18．01％,13．77％,8．22％和5．36％。     

3种落叶松苗期光能利用效率的比较

正林木90%以上的干物质来自光合作用,单位时间内光能利用效率(包括光能截获能力和光能转化效率)是衡量林木生长潜力的重要指标。光能截获能力主要与叶面积大小及其发展有关,光能转化效率主要与单叶光合速率有关。自发现光合速率在不同个体间存在明显差异后,以提高光能利用效率为目标的"高光效育种"受到育种学家的重视[1-3],而通过选配高光效种质进行有目的杂交已成为高光效育种的重要手段[4]。落叶松(Larix spp.)种间杂交     

Possibility of grouping of Cyclobalanopsis species (Fagaceae) grown in Japan based on an analysis of several regions of chloroplast DNA

Four regions of chloroplast DNA were sequenced as a prospective genetic marker to identify Japanese representatives of Cyclobalanopsis: Quercus acuta, Q. sessilifolia, Q. salicina, Q. myrsinaefolia, Q. glauca, and Q. gilva. We found that Q. gilva was distinguished from other species based on both the trnL-trnF and trnT-trnL intergenic spacers. The evidence shows good coincidence with the fact that Q. gilva has several peculiar morphological features distinguishable from those of other species. There was no difference in trnL intron and matK. Both trnT-trnL and trnL-trnF intergenic spacers are capable of being used as genetic markers to identify Q. gilva among Cyclobalanopsis species.Part of this paper was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 3–5, 1998     

Comparative analysis of the chemical constituents of two varieties of Pueraria candollei

A high-performance liquid chromatography (HPLC) method was developed to determine the contents of miroestrol and deoxymiroestrol in the tubers of Pueraria candollei var. mirifica and P. candollei var. candollei. The linear detection ranges were 0.78-25.00 μg/mL for miroestrol and 1.56-25.00 μg/mL for deoxymiroestrol. The limit of detection (LOD) and limit of quantification (LOQ) were 0.2 and 0.78 μg/mL, respectively, for miroestrol and 0.78 and 1.56 μg/mL, respectively, for deoxymiroestrol. Our results suggest that both varieties of P. candollei can produce miroestrol and deoxymiroestrol and that the developed HPLC method can be applied for quality control of plants and their products.     

FTIR spectroscopy, chemical and histochemical characterisation of wood and lignin of five tropical timber wood species of the family of Dipterocarpaceae

The goal of this study was to characterise chemical and histochemical properties of five dipterocarp timber wood species (Dipterocarpus kerrii, Hopea plagata, Parashorea malaanoman, Shorea almon, and Shorea contorta) differing in wood service life and utilisation. Wood of H. plagata, the most durable species, contained the lowest concentrations of nitrogen and ligno-protein, the highest C/N ratio and the lowest lignin concentration per dry mass but the highest lignin and extractive concentrations per wood density. FTIR spectroscopic studies of wood and isolated lignins of D. kerrii and H. plagata revealed differences compared to P. malaanoman and Shorea sp., which are species with short service life. Lignins of the Shorea/Parashorea species had a higher G/S ratio than those of H. plagata and D. kerrii. This was also evident from histochemical staining. Principle component analysis of FTIR spectra identified differences in both lignin composition and ligno-protein content as major source of variation.     

晋西黄土区三种林地土壤养分随林分生长的变化

[目的]研究不同林分类型以及林龄对晋西黄土区土壤养分的改良效应,以期为森林可持续经营提供参考、丰富该区域的生态服务评估资料。[方法]采用林分调查、土壤取样和室内分析方法,于2011年和2016年7—8月对3种不同林龄(山杨中龄林、油松幼龄林、侧柏中龄林)林地内的不同土层有机碳、全氮、全磷含量进行分析,并研究林内各土层间的C、N、P化学计量关系。[结果]表明:各林地土壤养分都有极强的表聚性,0~30 cm土层内有机质、全氮、全磷含量占0~100 cm土层的70%以上;经过5年时间,山杨、油松和侧柏林地0~50 cm土层内平均全氮含量分别增长了9.4%、7.4%、7.5%,全磷含量分别增长了11.6%、12.2%、21.4%;0~100 cm土层内碳储量分别增加了21.17、23.74、2.21 t·hm-2。不同林地之间土壤C:N值随土层深度逐渐减小,而N:P、C:P值随土层变化并没有规律;随着林龄的增加,土壤表层(0~10 cm)的N:P和C:P值明显减小,而C:N值变化不明显。[结论]根据全国土壤养分分级标准,试验林地内碳和氮含量较为丰富,而全磷平均含量为0.36~0.46 g·kg-1、为4~5级标准。在试验林地内,对土壤碳储量、全氮、全磷改良效果相对较好的分别为油松林、山杨林和侧柏林。     

Improvement of softening treatment technology of bamboo

In order to improve the efficiency of softening bamboo block when manufacturing bamboo veneer, chemistry reagents such as NaHCO₃ are often adopted during bamboo softening treatment. But the results of Fourier transform infrared spectroscopy (FTIR) showed that the band intensity at 1,733 cm⁻¹, assigned to C=O stretching vibration in xylan, was reduced in the spectrum of softening-treated bamboo with NaHCO₃ compared with that of not softening-treated bamboo and softening treatment of bamboo without NaHCO₃. That is to say, that the hemicellulose of bamboo was destroyed after softening treatment with NaHCO₃, which meant that softening treatment of bamboo with NaHCO₃, is not a perfect softening treatment method. Thus, in this paper a softening technology at 120°C for 30 min in a closed container was adopted. The results of FTIR show that there was almost no difference in FTIR spectra between no softening treatment of bamboo and softening treatment of bamboo at 120°C for 30 min, which meant that softening treatment at 120°C for 30 min had no effect on the composition of bamboo. The results of dynamic mechanical analysis (DMA) show that T _g of not softening-treated bamboo was 120°C, while T _g of softening-treated bamboo at 120°C for 30 min was 88°C. T _g of softening-treated bamboo at 120°C for 30 min decreased by 26.7% compared with that of not softening-treated bamboo. The results of hardness show that the hardness of bamboo strip after a softening treatment for 30 min at 120°C decreased by 42.0–54.6% compared with that of not softening-treated bamboo. The results of hardness and DMA show that the effect of softening treatment of bamboo at 120°C for 30 min was resultful.