松球壳孢菌菌落生长速度对比研究

利用79个辽宁松球壳孢菌菌株与4个A型和B型标准菌株及4个美国菌株进行菌落生长速度对比研究发现,除个别菌株外,辽宁菌株的菌落生长速度显著慢于供试的A型标准菌株和美国菌株;美国菌株与A型标准菌株的菌落生长速度相近,显著快于B型标准菌株;辽宁菌株之间也有显著差别。同时发现,光照可加快菌落离体生长速度。     

松球壳孢菌菌落及孢子形态学对比研究

通过79个辽宁松球壳孢菌菌株与4个A型和B型标准菌株、5个美国菌株在菌落和分生孢子形态方面的对比研究，发现辽宁的菌株在形态上基本一致。辽宁菌株与美国的类型A相近，主要表现在孢子表面平滑，通常无隔或有1个隔，在成品PDA培养基上产生绒毛状、白色至灰色菌落。不同之处在于，辽宁菌株在自制PDA培养基上形成贴在培养基表面的菌落——与类型B相似，分生孢子长度介于A型和B型之间或与后者相近。5个美国菌株与类型A一致。同时发现，培养基的来源对菌落形态研究非常重要；光照使菌落气生菌丝有所减少且出现绿色；培养基和寄主种类对孢子大小有影响。     

松球壳孢菌的形态学与18S rDNA ITS序列比较分析

以研究东北三省樟子松球壳孢菌Sphaeropsis sapinea的遗传多样性为目的,自黑龙江、吉林、辽宁省不同地区收集、分离获得樟子松球壳孢菌45个菌株,寄主均为樟子松;收集美国菌株2个,分别分离自脂松、班克松.运用形态学和分子生物学手段比较47个菌株的形态学及18S rDNAITS序列.结果表明:(1)所有47个菌株在形态上没有明显差别;(2)除美国菌株STBl外,其他46个菌株在培养特性上没有明显差别;(3)东北三省的45个菌株之间的遗传距离均小于0.09,与寄主为脂松的A型菌株(STAl)亲缘关系较近,相似度高于98%,与寄主为班克松的B型菌株(STBl)遗传距离为0.13,亲缘关系较远.(4)同一地域、不同地域来源的菌株其ITs序列相同,而地理来源相同的菌株其ITs序列也存在一定的差异;(5)相同寄主上的菌株其ITs序列存在差异,而不同寄主上的菌株其ITS序列相同.综上得出以下结论:东北三省不同地区樟子松上的45个松球壳孢菌菌株为A型.球壳孢菌菌株之间的遗传差异与菌株的寄主及地域性没有明显的关系.     

毒蘑菇菌株及毒素粗提液对樟子松枯梢病菌生长的影响

厚环鹅膏、鹅膏菌、珊瑚菌、白霜杯伞、冠状柄环菇、细鳞环柄菇、鳞柄白鹅膏、绒白乳菇、毒蝇鹅膏9个毒蘑菇菌株及毒素粗提液对樟子松枯梢病原菌菌丝生长影响的研究结果表明:除厚环鹅膏和鹅膏菌外,其他7个菌株对病原菌生长均有一定的抑制作用;鳞柄白鹅膏和细鳞环柄菇相对抑制效果最好,分别为10.80和10.40。除毒蝇鹅膏外,其他8个菌株的毒素粗提液对病原菌菌丝生长均有一定的抑制作用,珊瑚菌和绒白乳菇毒素粗提液的抑菌效果最好,抑菌率分别达到63.89%和58.89%。     

The aggressiveness of Sphaeropsis sapinea on Austrian pine varies with isolate group and site of infection

The aggressiveness of the A and B isolate groups (morphotypes) of Sphaeropsis sapinea on shoot tips and lower stems of Austrian pine (Pinus nigra) was compared. The distinct differences in aggressiveness between the two S. sapinea groups, previously reported for other conifers, are confirmed for Austrian pine. However, the relative aggressiveness of the B group isolate varied by site of infection. Although the B group isolate of S. sapinea was not aggressive on shoot tips of Austrian pine, it was aggressive on stems of this host.     

Association of Sphaeropsis sapinea with insect‐damaged red pine shoots and cones

The association of the shoot blight and canker pathogen Sphaeropsis sapinea with red pine (Pinus resinosa) shoots and cones damaged by insects (especially Dioryctria sp.) was investigated. Samples from a single plantation approximately 35 years old, in Sauk Co., Wisconsin and also from three plantations, between approximately 40 and 50 years old, located in an area of pine shoot moth activity in the preceding year in Adams Co., Wisconsin were visually examined. Samples were arbitrarily collected from trees felled in the first plantation in May. Pycnidia of S. sapinea and insect damage were observed on 56 of 91 (62%) of closed cones and 17 of 165 (7%) of previous year's shoots. In the absence of insect damage, pycnidia of the pathogen were identified only on eight of 91 (9%) closed cones and never on previous year's shoots. In each of the other three plantations, 10 trees were located at intervals along transects in mid‐June; one branch from the lower half of the crown per tree was pruned off, and both current and previous year's shoots were examined. Insect damage and S. sapinea pycnidia were too rare on current year's shoots to draw any conclusions. Insect damage occurred on 20–40% of over 2000 previous year's shoots that were examined, but pycnidia of the pathogen were identified on only about 5%. Although infrequent, S. sapinea was identified in association with insect‐damaged previous year's shoots from these three plantations three times more frequently than those without insect damage. Random amplified polymorphic DNA (RAPD) markers from eight randomly selected isolates were consistent with the A group of S. sapinea, which can be aggressive on red pine. This ability to exploit insect‐damaged shoots may facilitate long‐term persistence of S. sapinea at low disease incidence and severity. The potential role of insect wounds as infection courts and insects as vectors of this important pathogen of pines deserves further study.     

Genotypic diversity and distribution of Sphaeropsis sapinea within Pinus radiata trees from northern Spain

Sphaeropsis sapinea is an important latent pathogen of Pinus spp., outbreaks of which have a considerable impact on plantations. This study considers the population diversity and distribution of S. sapinea in northern Spain at different spatial scales from single plantations to a wide area covered by Pinus radiata trees. Estimation of genotypic diversity is an important component of the analysis of the genetic structure of plant pathogen populations. Ten simple sequence repeat (SSR) markers were used, together with vegetative compatibility tests, to study the genetic diversity among S. sapinea isolates. Polymorphism analysis at SSR loci is a simple and direct approach for estimating the genetic diversity of S. sapinea isolates. From a total of 86 isolates collected from four different areas, 14 microsatellite haplotypes and 13 vegetative compatibility groups (VCGs) were identified. The percentage of maximum genotypic diversity, based on Stoddart and Taylor's index, for microsatellites of the northern Spain population ranged from 14.6% to 38.1% and from 8.0% to 29.4% for VCGs. Analysis of these markers and vegetative compatibility groups confirmed that S. sapinea reproduces mainly asexually due to its reduced genotypic diversity in spatially close populations. Isolates of S. sapinea from northern Spain populations were predominantly monomorphic at the tested SSR loci. Vegetative compatibility groups also indicate a low level of genetic variability in these samples, which appear to be clonal.     

不同生物控制技术对樟子松林分生长及松枯梢病发病程度的影响

通过对樟子松林分进行生物控制技术的研究可知,在中龄林进行施用菌剂、切根、人工整枝试验对促进樟子松树势的恢复、树木胸径生长、增强树势等方面等有明显作用:在胸径生长方面,3个处理与对照差异显著,其中切根5年后的樟子松林分胸径生长高于施用菌剂和人工整枝处理,年生长量达1.89cm;3个处理与对照相比,大大减少了松枯梢病发病机率,其中修枝处理防控病害的效果最好。     

Organ-dependent induction of systemic resistance and systemic susceptibility in Pinus nigra inoculated with Sphaeropsis sapinea and Diplodia scrobiculata

Systemic induced resistance (SIR) is a well-known host defense mechanism against pathogen attack in herbaceous plants, but SIR has only recently been documented in conifers. We tested if inoculation of Austrian pine (Pinus nigra Arnold) with Sphaeropsis sapinea (Fr.:Fr.) Dyko and Sutton or Diplodia scrobiculata de Wet, Slippers and Wingfield results in SIR or systemic induced susceptibility (SIS) to subsequent colonization by S. sapinea. Induction at the stem base resulted in significant (P < 0.01) SIR in the upper stem, and induction in the upper stem resulted in significant (P < 0.05) SIR at the stem base, indicating that SIR is bidirectional in Austrian pine. However, inoculation at the stem base resulted in significant (P < 0.01) SIS in shoot tips, demonstrating that, in the same host species, the expression of resistance can be organ-dependent, resulting in either SIR or SIS depending on the site of challenge infection. Systemic induced resistance in the stem was associated with induced lignification, supporting a potential role for this defense mechanism in disease resistance. Systemic induced susceptibility has been documented before, but this is the first demonstration of organ-dependent expression of both SIR and SIS in a tree or any other plant.     

Induction of phenylalanine ammonia lyase activity and control of Sphaeropsis sapinea infection in Pinus radiata by 5-chlorosalicylic acid

Phenylalanine ammonia lyase (PAL) activity increased rapidly in Pinus radiata seedlings after treatment with 2 mm 5-chlorosalicylic acid (5CSA) and peaked after 48 h at four-times the level of the control. Elevation of PAF is often associated with the induction of host resistance mechanisms. Thus, effects of 5CSA on subsequent infection of P. radiata by Sphaeropsis sapinea was investigated. Only one out of 16 seedlings treated with 2 mm 5CSA, 4 days before inoculation, developed deadtop compared to 14 of the controls. The 5CSA was directly inhibitory at this concentration and reduced growth rate of S. sapinea on agar by 27%. However, antifungal activity does not fully account for the observed disease control afforded by 5CSA since 0.5 mm and 0.25 mm 5CSA, which did not inhibit growth of S. sapinea, significantly reduced the incidence of deadtop. Furthermore, 1 mm 5CSA protected seedlings against fresh inoculation challenge for up to 32 days after application. Such durable resistance is unlikely to be attributable to the direct effects of the applied compound and may suggest the involvement of inducible host resistance mechanisms.     

Surveys for asymptomatic persistence of Sphaeropsis sapinea on or in stems of red pine seedlings from seven Great Lakes region nurseries

The fungus Sphaeropsis sapinea persists on or in stems of asymptomatic red pine (Pinus resinosa) nursery seedlings, and proliferates to cause collar rot and mortality after planting. In the spring of 2002, seven nurseries were surveyed to determine the potential range in frequency of asymptomatic persistence: three operated by Wisconsin Department of Natural Resources (DNR), two by Minnesota DNR, one by Michigan DNR, and one by USDA Forest Service (in Michigan). At each nursery five groups of 20 asymptomatic red pine seedlings were collected near an inoculum source (red pine windbreak), if present, and five groups of 20 asymptomatic seedlings were collected away from such a source (1400 seedlings total). A segment of the lower stem/root collar from each seedling was surface disinfested and incubated on tannic acid agar. Transfers were made from resulting colonies and the pathogen identified from pycnidia and conidia produced in culture. The pathogen was identified from asymptomatic seedlings collected in all Wisconsin and Minnesota nurseries, but was never detected from seedlings from the Michigan DNR or USDA Forest Service nurseries. Frequencies of detection were greater (as high as 88%) from asymptomatic seedlings near red pine windbreaks including diseased trees than from seedlings distant from such windbreaks. A subset of isolates from asymptomatic seedlings was characterized using inter‐simple sequence repeat–polymerase chain reaction analysis. Most isolates were the A group of S. sapinea, but B group isolates (recently named Diplodia scrobiculata) were also obtained from one nursery. One Minnesota nursery was more extensively sampled in 2003, with 17–44 groups of five asymptomatic red pine seedlings collected in four separate fields (525 seedlings total). The mean frequency of detection of the pathogen in these four fields ranged from 40 to 71%. Persistence of S. sapinea on or in asymptomatic seedlings continues to be problematic, not only because of the potential for subsequent seedling mortality, but also as a means by which a pathogen may be widely distributed.     

Responses of black spruce (Picea mariana) and tamarack (Larix laricina) to flooding and ethylene

Black spruce (Picea mariana (Mill.) BSP) and tamarack (Larix laricina (Du Roi) K. Koch) are the predominant tree species in the boreal peatlands of Alberta, Canada, where low nutrient availability, low soil temperature and a high water table limit their growth. Effects of flooding for 28 days on morphological and physiological responses were investigated in greenhouse-grown black spruce and tamarack seedlings in a growth chamber. Flooding reduced root hydraulic conductance, net assimilation rate and stomatal conductance, and increased water-use efficiency (WUE) and needle electrolyte leakage in both species. Although flooded black spruce seedlings maintained higher net assimilation rates and stomatal conductance than flooded tamarack seedlings, flooded tamarack seedlings were able to maintain higher root hydraulic conductance than flooded black spruce seedlings. Needles of flooded black spruce developed tip necrosis and electrolyte leakage after 14 days of flooding, and these symptoms were subsequently more prominent than in needles of flooded tamarack seedlings. Flooded tamarack seedlings exhibited no visible injury symptoms and developed hypertrophied lenticels at their stem base. Application of exogenous ethylene resulted in a significant reduction in net assimilation, stomatal conductance and root respiration, whereas root hydraulic conductivity increased in both species. Thus, although flooded black spruce seedlings maintained a higher stomatal conductance and net assimilation rate than tamarack seedlings, black spruce did not cope with the deleterious effects of prolonged soil flooding and exogenous ethylene as well as tamarack.     

Identification of low productivity sites for European larch (Larix decidua Miller) in Maine,USA

As silvicultural capital becomes limited, allocation of funds to high quality sites becomes critical and sites with low productivity potential should be avoided. Data collected from 31 plots located in 12 plantations established between 1930 and 1982 throughout central Maine were used to develop a soil-based rule to identify sites having a low productivity potential for European larch in Maine, thereby removing them from consideration for plantation establishment. Stepwise regression and discriminant analyses identified several variables that were associated with site index at an index age of 20 years breast height (SI₂₀): solum thickness, B horizon clay content, and B horizon exchangeable K. Using these variables, a classification rule was developed to classify sites into 2 categories (poor, average SI₂₀=14.7 m; and good, average SI₂₀=17.7 m). Cross-validation demonstrated that the classification functions correctly identified 88% of the poor sites and 81% of the good sites.     

Effects of high drying temperatures and restraint on twist of larch (Larix)

Abstract

During drying, timber changes its shape, mainly as a result of specific properties such as shrinkage anisotropy, radial differences in longitudinal shrinkage and spiral grain. The distortion, causing severe downgrading, can be reduced by restraining the timber and by using special drying schemes. The research described here is related to a project on the improvement of shape stability of Norway spruce. In the present part, different larch species from three stands were dried at high temperatures (80, 120 and 170°C). The effects of restraint during presteaming, drying and steaming on short-term twist reduction were investigated. The permanency of drying distortions was investigated in subsequent moisture cycling. Results showed a clear dependency of twist on the distance to pith. Restrained specimens sawn close to pith experienced reduced twist. This twist reduction was permanent during subsequent moisture variations. Drying temperature did not significantly influence twist and twist amplitude in moisture cycling.     

Effects of high drying temperatures and restraint on twist of larch (Larix)

During drying, timber changes its shape, mainly as a result of specific properties such as shrinkage anisotropy, radial differences in longitudinal shrinkage and spiral grain. The distortion, causing severe downgrading, can be reduced by restraining the timber and by using special drying schemes. The research described here is related to a project on the improvement of shape stability of Norway spruce. In the present part, different larch species from three stands were dried at high temperatures (80, 120 and 170°C). The effects of restraint during presteaming, drying and steaming on short-term twist reduction were investigated. The permanency of drying distortions was investigated in subsequent moisture cycling. Results showed a clear dependency of twist on the distance to pith. Restrained specimens sawn close to pith experienced reduced twist. This twist reduction was permanent during subsequent moisture variations. Drying temperature did not significantly influence twist and twist amplitude in moisture cycling.     

Analysis of Chinese larch (L. gmelini) SCMP bleachability

The dissolution of lignin and major ploysaccharides from sulfonated chemimechanical pulp (SCMP) ofL. gmelini during sulfonation and defibration, the tharacteristics of lignin and bleachability of larch SCMP were studied using gas chromatography (GC), IR, UV spectrometry, ’H-NMR, “C-NMR and chemical analyses.     

TMS天目丝增抗剂在落叶松育苗中的应用

应用2000,1000,500,250,125,62mLL-1TMS天目丝增抗剂对200株长白落叶松苗进行6小时浸根,在生长季节(5月30日至10月20日)对经过天目丝增抗剂处理的造林苗每隔15天测定一次苗木的高生长、地径、主根长度,侧根数。实验结果表明,天目丝增抗剂处理可以极大地促进长白山落叶松苗木生长并能提高苗木质量。500mLL-1TMS处理的苗木生长效果最好,与常规育苗相比,高生长平均增加42.5%,地径生长平均增加30.7%,主根长平均增加14.0%,侧根数平均增加31.6%;Ⅰ级苗和Ⅱ级苗各占一半,没有Ⅲ级苗,显著地提高了经济效益。表3参8。     

Pathogenicity of Bursaphelenchus sexdentati,Bursaphelenchus leoni and Bursaphelenchus hellenicus on European pine seedlings

In Greece extensive pine wilting is associated with the presence of nematodes of the genus Bursaphelenchus. In order to check the pathogenicity of Bursaphelenchus sexdentati, Bursaphelenchus leoni and Bursaphelenchus hellenicus, inoculation tests were carried out on 3‐year‐old seedlings of Pinus brutia, Pinus halepensis, Pinus nigra, Pinus pinaster and Pinus sylvestris. For inoculations, 6000 nematodes in 0.5 ml of water were used per seedling. Bursaphelenchus sexdentati proved to be highly virulent causing mortality of up to 100%, followed by B. leoni whereas B. hellenicus was nonpathogenic.     

Interacting effects of physical environment and anthropogenic disturbances on the structure of European larch (Larix decidua Mill.) forests

Most forested landscapes have been strongly influenced by humans, and hence prediction of response to future perturbations or climate change requires understanding of the interaction among human influences and the abiotic environment. Environmental and anthropogenic influences on forest structure in Larix decidua Mill. stands were investigated in two watersheds of the central Italian Alps (Valtellina, SO). We related three data sets (forest structure, anthropogenic influences, and topography) using ordination methods. Path models of correlative and causal relationships between these sets of variables were developed and used to differentiate the two watersheds with respect to levels of historical human influence. The two study areas (Musella and Ventina) were characterized by strong climatic and topographic gradients as well as a long history of human settlement, although historical intensity of agricultural activities was much greater for Musella. We hypothesized a weaker influence of abiotic variables on forest structure where the intensity of the primary human disturbance factors, forest thinning and cattle grazing, had been strongest.     

European larch and eastern white pine respond similarly during three years of partial defoliation

To test whether trees with different leaf life spans respond differently to defoliation, eastern white pine (Pinus strobus L.) and European larch (Larix decidua Mill.) trees (9 years old in 1991) were partially defoliated by hand between July 1 and 10 in 1989, 1990 and 1991. At the end of 1991, trees of both species had received either 0, 1, 2 or 3 years of defoliation. Trees that received only 1 year of defoliation were defoliated in 1989. Variables measured included photosynthesis, twig water potential, leaf mass per area and leaf nitrogen concentration. There were few significant responses to defoliation in any of the three years of treatment in either species, and only the current-year defoliation treatments caused significant responses. Both species had reduced photosynthetic rates and less negative twig water potentials in response to defoliation in 1989. In 1990 and 1991, the defoliation treatments had no significant effect on any of the parameters measured in European larch. In 1990, there was a significant reduction in foliar nitrogen concentration in eastern white pine in response to defoliation in 1990. In 1991, eastern white pine had significantly less negative twig water potentials in response to defoliation in 1991. Leaf mass per area was not affected by defoliation in either species. We conclude that, for European larch and eastern white pine, differences in leaf life span have no effect on leaf- and twig-level responses to defoliation.