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1.
The interactions between pine wood nematode and three bacterium strains isolated from the nematode, Bursaphelenchus xylophilus, which are two strong pathogenic bacterium strains, Pseudomonas fluorescens GcM5-1A and Pseudomonas putida ZpB1-2A and a weak-pathogenic bacterium strain, Pantoea sp. ZM2C, were studied. The result showed that the strong-pathogenic GcM5-1A strain and ZpB1-2A strain significantly increased
fecundity, reproduction rate, and the body volume of the adult nematode. Meanwhile, pine wood nematodes significantly promoted
reproduction of the two strong-pathogenic bacterium strains. However, the weak-pathogenic bacterium strain, ZM2C, completely
inhibited reproduction of pine wood nematodes. Aseptic pine wood nematodes significantly inhibited reproduction of the strain
ZM2C. The results indicated that mutualistic symbiosis exists between pine wood nematodes and the two pathogenic bacteria
it carries. The phenomenon showed that the pathogenic bacteria carried by the nematode were not accidentally contaminated,
but rather had existed as symbionts of the nematode with which it had coevoluted over a long period. The role of mutualistic
symbiosis in the process of pine wilt disease was also discussed.
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Translated from Journal of Nanjing Forestry University, 2005, 29(3): 1–4 [译自: 南京林业大学学报, 2005, 29(3): 1–4] 相似文献
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Simulated acid rain (SAR) at three pH levels (pH 4, 3, 2) was applied to only the top or both the top and roots of 4-month-old
Japanese black pine seedlings repeatedly for two months. Then the seedlings were inoculated with a virulent isolate (S10)
of pinewood nematode,Bursaphelenchus xylophilus. The exposure to SAR at any level did not kill the seedlings. When inoculated with nematodes, however, the nematode population
build-up was significantly higher in the seedlings pretreated with SAR at any level than in the control at the 7th and 17th
day after inoculation, and subsequent disease symptom development was also significantly accelerated by the exposure to SAR
at pH 2 and 3. This result indicates that even acid rain at pH 4 has the potential for promoting population growth of pinewood
nematodes in 4-month-old Japanese black pine seedlings. 相似文献
4.
松材线虫病致病机理的研究进展 总被引:35,自引:1,他引:35
该文对松材线虫病的致病机制的研究进行了概述。目前对松材线虫病的病原有两种看法,一种认为松材线虫是惟一病原,另一种认为病原为松材线虫和细菌两种生物。对于松材线虫的致病机理,目前存在3种观点。第1种观点认为松材线虫的酶使松树薄壁细胞的细胞壁和细胞膜遭到破坏,树脂不正常地从树脂道中渗漏并扩散到相邻的管胞中,使水分输导受阻,导致萎蔫。第2种观点认为松树感染了松材线虫后,木质部内挥发性萜烯类物质的含量增加,这些物质进入管胞在管胞中形成空洞,致使水分输导受阻。第3种观点认为松树感染松材线虫后,体内产生有毒物质,这些物质使松树萎蔫。 相似文献
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研究和综述了寄生松科植物的伞滑刃属(Bursaphelenchus)的线虫23种,松材线虫的寄主松科植物108种、携带昆虫40种及发病的环境条件。 相似文献
7.
Katsumi Togashi Kaori Aida Katsunori Nakamura Takao Horikoshi Fumiki Takahashi 《Journal of Forest Research》1997,2(1):39-43
To evaluate the effect of adjacent tree species on the susceptibility of Japanese black pine (Pinus thunbergii) to pine wilt disease, an inoculation experiment was conducted usingP. thunbergii seedlings potted with seedlings of six tree species,i. e. Alnus sieboldiana, Eurya japonica, Lespedeza bicolor formacutifolia, Pinus thumbergii, Robinia pseudo-acacia andSarothamus scoparius. About ten months after planting, they were inoculated with the pinewood nematode (Bursaphelenchus xylophilus) in early July 1992. After that, the proportion of pine seedlings with completely discolored foliage increased more quickly
when the seedlings were potted withR. pseudo-acacia, S. scoparius orA. sieboldiana than when potted withP. thunbergii, L. bicolor orE. japonica. At the end of the study period, 17 weeks after inoculation, it reached 90.6%, 90.0%, 87.5%, 72.7%, 63.3%, and 59.4% when
the pine seedlings were potted withR. pseudo-acacia, S. scoparius, A. sieboldiana, P. thunbergii, L. bicolor andE. japonica, respectively. This indicated that the susceptibility ofP. thunbergii seedlings to pine wilt disease was influence by the species of adjacent trees. 相似文献
8.
松材线虫病检疫检验取样方法的研究 总被引:2,自引:0,他引:2
对24个样本分别采用木条(10g)和0.6cm钻头钻取的木屑(10g)作为分离材料进行线虫分离,利用方差分析的方法对线虫分离结果进行分析,其差异不显著,两种取样方法对线虫检验的结果没有影响,对19个样本分别采用木条(10g)和用1cm的钻头钻取的木屑(10g和5g)3种分离材料进行线虫分离,同样利用方差分析对虫分离结果进行分析,其差异也不显著,3种分离材料对线虫检验结果同样没有影响。因此,利用电钻取样是可行的,这种方法快速简便,易于推广应用。 相似文献
9.
Juan Shi Youqing Luo Xiaosu Yan Weiping Chen Ping Jiang 《Frontiers of Forestry in China》2009,4(1):117-122
Pine wood nematode (PWN, Bursaphelenchus xylophilus), originating from North America, causes destructive pine wilt disease. Different pine forest ecosystems have different resistances
to B. xylophilus, and after its invasion, the resilience and restoration direction of different ecosystems also varies. In this study, an
interpretative structural model was applied for analyzing the response of pine forest ecosystem to PWN disturbance. The result
showed that a five-degree multi-stage hierarchical system affected the response of the pine forest ecosystem to PWN disturbance,
in which direct affecting factors are resistance and resilience. Furthermore, the analysis to the 2nd, 3rd and 4th degree
factors showed that not only does distribution pattern of plant species and pine’s ecological features affect the resistance
of pine forests’ ecosystem, but removal of attacked trees and other measures also influence the resistance through indirectly
affecting the damage degree of Monochamus alternatus and distribution pattern of plant species. As for resilience, it is influenced directly by soil factors, hydrology, surrounding
species provenance and biological characteristics of the second and jointly dominant species, and the climate factors can
also have a direct or indirect effect on it by affecting the above factors. Among the fifth elements, the elevation, gradient
and slope direction, topographical factors, diversity of geographical location and improvement of prevention technology all
influence the response of pine forest ecosystem to PWN disturbance.
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Translated from Scientia Silvae Sinicae, 2007, 43(8): 85–90 [译自: 林业科学] 相似文献
10.
一种利用黑松枝条筛选杀松材线虫剂的生测方法 总被引:1,自引:0,他引:1
该文介绍了一种利用黑松枝条进行化合物对松材线虫作用的生测方法。通过研究枝条的接种线虫数量、含水量以及灭菌处理后对松材线虫繁殖的影响,确定了合适的生测条件,并对几种生测方法的优缺点进行了讨论。 相似文献
11.
Takefumi Ikeda 《Journal of Forest Research》1996,1(4):223-226
The effect of water-stress conditioning on water relations and histological features ofPinus thunbergii Parl. inoculated with avirulent isolate ofBursaphelenchus xylophilus (Steiner and Buhrer) Nickle, pine wood nematode, were investigated. Pines were kept under 8 days cycle of severe water stress.
One-half of the water-stressed pines died as a result of infection by avirulent pine wood nematode and water stress tended
to induce increased susceptibility and/or decreased resistance of pines to avirulent pine wood nematode. In dead pines, the
water conducting function of xylem was lost, and all of the parenchyma cells died. In surviving pines, the xylem hydraulic
conductivity and the xylem water content were significantly reduced (12 to 23% and 77 to 83%, respectively) compared to controls.
Safranin dye perfusion of excised axis stem segments indicated that the water conductance was limited to the very narrow peripheral
area of xylem. Embolism caused by cavitation in the tracheids occurred in the central part of xylem and in that dysfunctional
region of the xylem the axial parenchyma cells surrounding the epithelial cells, and ray parenchyma cells partly degenerated
but the epithelial cells survived. The disruption of tracheid shape observed in surviving pines indicates that avirulent pine
wood nematode temporarily disturbed cell division of the cambium. Considering the differences in responses between dead pines
and surviving pines after inoculation with avirulent pine wood nematode, the death of water-stressed pines apparently resulted
from death of cells, in particular the vascular cambium and the loss of xylem hydraulic function by cavitation. 相似文献
12.
Three- or 4-year-old Japanese black pine seedlings were exposed to simulated acid rain (SAR) at pH 3 for two months, then
inoculated with a virulent isolate (S 10) of pinewood nematodes. The experiments were repeated three times in 1996–1998. The
exposure to SAR killed no seedlings, and retarded the development of disease symptoms in the seedlings inoculated with nematodes.
In the experiments in 1996 and 1997, however, cessation of resin exudation, and primary decrease in the xylem conductivity
occurred earlier in the seedlings exposed to SAR than in those exposed to tap water as a control. These results imply that
acid rain at pH 3 influenced an increase in some resistance of Japanese black pine seedlings to pinewood nematode, and that
this improved resistance could potentially overcome damage caused by acid rain. The exposure to SAR did not have any significant
effect on the water relations of the seedlings itself, suggesting that retardation of the symptom development after the exposure
to SAR could not be attributed to the improvement in the water relations.
This work was supported in part by a Grants-in-Aid for Scientific Research from the Japan Forest Technical Association (JAFTA). 相似文献
13.
通过林间设置松褐天牛Monochamusalternatus引诱剂,对引诱到的松褐天牛进行分离,10分钟后就能检查出有无病原线虫的存在,50分钟后线虫全部游离到水中。该方法具有在病害传入早期及时发现和检测时间短等优点 相似文献
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Jiying Song Youqing Luo Juan Shi Xiaosu Yan Weiping Chen Ping Jiang 《Frontiers of Forestry in China》2006,1(4):460-463
In November 2003 and June 2004, the insect borers and their spatial distribution within Pinus massoniana were investigated in Zhoushan City, in East China’s Zhejiang Province, where pine wood nematode (Bursaphelenchus xylophilus) are typically found. The niche width, proportional similarity of niche and the niche overlap of dominant species of dying
trees were computed. Results show that five insect species infect and damage Pinus massoniana, which had been infected by pine wood nematodes, among which four are wood boring beetles and one termite. Species within
host trees vary from winter to summer and all the species have their own niche width, proportional similarity of niche and
the niche overlap. They can achieve competitive equilibrium and coexistence according to their biological characteristics
and life habits.
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Translated from Journal of Beijing Forestry University, 2005, 27(6): 108–111 [译自: 北京林业大学学报, 2005, 27(6): 108–111] 相似文献
18.
Physiological process of the symptom development and resistance mechanism in pine wilt disease 总被引:4,自引:0,他引:4
Kenji Fukuda 《Journal of Forest Research》1997,2(3):171-181
Pathophysiological changes during the symptom development of pine wilt disease are reconsidered from recent investigations.
The symptom development is divided into two stages: the early and the advanced stages. In the early stage, small number of
nematodes migrate in cortex, then in xylem of the stem, and induce denaturation and necrosis of parenchyma cells. These changes
in parenchyma are regarded as defense reactions of pines which result in terpene synthesis in xylem cells and embolism in
tracheids. Such changes in the early stage can be induced in both susceptible and resistant pine species by either virulent
or avirulent isolates of pinewood nematode (Bursaphelenchus xylophilus), or byB. mucronatus. No change occur in physiological status of leaves, and nematode reproduction is suppressed during this stage. Pine trees
can survive if symptom does not progress from this stage. The symptoms of the advanced stage usually occur only in susceptible
pines infected by virulent nematode isolates. At the beginning of the advanced stage, enhanced ethylene production by stem
which coincides with cambial destruction occurs, and results in embolism of the outermost xylem in the portion. The embolism
causes decrease in leaf water potential and cessation of photosynthesis. After cessation of photosynthesis, symptoms develop
drastically with a burst of nematode population. There seems to be some unknown mechanism which suppress nematode reproduction
and invasion to the cambial zone. This mechanism is thought to be photosynthesis-dependent, so that in photosynthesis-decrased
conditions, even avirulent nematodes can multiply and invade cambium to induce tree death. Water stress in hot and dry summer
should accelerates symptom development from the early to the advanced stage through such decrease of photosynthesis-dependent
“cambial resistance”. 相似文献
19.
日本松材线虫病研究的最新动向 总被引:11,自引:0,他引:11
该文重点对近2a日本松材线虫病的研究文献进行整理分析。目前松材线虫病的研究仍是日本国森林病虫害的主要研究课题。在松树的抗(感)病机理、线虫在树体内的活动与增殖规律、线虫与天牛的关系、生物防治以及新技术在研究中的应用等方面取得较大进展。 相似文献
20.
绿僵菌Mf2菌株对松材线虫的毒力测定 总被引:1,自引:0,他引:1
为探索绿僵菌Metarhigium anisopliae Mf2菌株对松材线虫的毒杀效果,从4种常见培养基PDA,PPDA,SDAY,SMAY中选择一种最适于绿僵菌Mf2菌株营养生长及产孢的培养基,测定该菌株对松材线虫的毒杀活性。结果表明,Mf2菌株在PPDA培养基中生长速度最快,14 d后菌落直径大于其他3种培养基,为76.00 mm;培养14 d后PPDA培养基中菌株产孢量最高,为5.667×1010个孢子,显著高于其他培养基上的产孢量,约为处于第2位的PDA培养基上产孢量的2.5倍;绿僵菌Mf2菌株具有较高杀线虫活性,处理36 h后校正死亡率为98.52%。绿僵菌Mf2菌株对松材线虫毒力测定表明具有很高的毒性,有良好的应用前景。 相似文献