共查询到4条相似文献,搜索用时 15 毫秒
1.
Jan Cedervind§ Mattias Pettersson† Bo Långström 《Agricultural and Forest Entomology》2003,5(3):253-261
Abstract 1 After a 1‐year, extensive pine looper (Bupalus piniaria) outbreak, plots were laid out to study tree susceptibility to attack, and performance of Tomicus piniperda in pine trees suffering from varying levels of defoliation. 2 Tomicus piniperda was the dominating stem‐attacking species among the primary stem colonizers, and 82% of all trees that died had been colonized by T. piniperda. 3 Beetle attacks primarily struck severely defoliated trees, i.e. trees that suffered from 90% to 100% defoliation. 4 Beetle attacks peaked in the second year after cessation of the outbreak, and suppressed trees were both more frequently attacked and more susceptible to beetle attack than intermediate and dominant trees. 5 Trees surviving beetle attacks carried more foliage than trees that did not survive the attacks. 6 A single year of severe defoliation is enough to render pine trees susceptible to secondary pests, such as T. piniperda. 相似文献
2.
Systemic induction of phloem secondary metabolism and its relationship to resistance to a canker pathogen in Austrian pine 总被引:1,自引:0,他引:1
Wallis C Eyles A Chorbadjian R McSpadden Gardener B Hansen R Cipollini D Herms DA Bonello P 《The New phytologist》2008,177(3):767-778
The mechanisms and conditions affecting expression of systemic induced resistance (SIR) in pine are not clearly understood. Two hypotheses were tested here: that SIR against a pathogen induced by either a pathogen or an insect involves coordinated shifts in phloem secondary metabolism; and that fertility affects the production of these compounds. To test these hypotheses, a tripartite system was used comprising Austrian pine (Pinus nigra) grown under three different fertility regimes, the fungal pathogen Diplodia pinea, and the defoliator Neodiprion sertifer. Fungal induction led to systemic accumulation of lignin, phenolic glycosides and stilbenes, whereas insect defoliation led to an increase in germacrene D concentration in branch phloem. Fertility affected the concentrations of only the phenolic glycosides. Multivariate analyses showed coregulation of compounds within at least three consistent groupings: phenolic glycosides, stilbenes and monoterpenes. As groups and as individual compounds, accumulation of phenolic glycosides and stilbenes was negatively correlated with disease susceptibility. The experimental manipulation of the phenolics and terpenoids metabolic networks achieved in this study by biotic induction and changes in nutrient availability suggests that lignin, phenolic glycosides and stilbenes are important biochemical factors in the expression of SIR against the pathogen in this system. 相似文献
3.
Host finding in the pine weevil Hylobius abietis: effects of conifer volatiles and added limonene 总被引:2,自引:0,他引:2
G. Nordlander 《Entomologia Experimentalis et Applicata》1991,59(3):229-237
The attraction of Hylobius abietis (L.) (Coleoptera: Curculionidae) to -pinene was recently shown to be inhibited by limonene. This study shows that added limonene also affects the response of H. abietis to odours from natural host material. The experiments included both pieces of Scots pine suspended in pitfall traps and planted pine seedlings that had either been manually wounded or left intact. By adding a limonene dispenser, the catch of pine weevils in pine-baited traps was reduced by about 80–90% in spring and autumn and by about 40–50% in summer. Limonene substantially reduced the rate at which manually wounded seedlings were attacked by weevils in spring and autumn. For intact seedlings, a limonene-induced reduction in attack rate was found only in autumn. In the absence of limonene, a small wound made on the stem of a seedling increased its probability of being attacked by about fivefold. This figure was estimated by comparing data from all experimental periods with a model assuming a constant ratio of attack rates for the two kinds of seedlings. 相似文献
4.
Root deformation in plantations of container-grown Scots pine trees: effects on root growth,tree stability and stem straightness 总被引:4,自引:0,他引:4
Root system deformation was studied in 23 Scots pine (Pinus sylvestris L.) stands in central Sweden. The study comprised both
plantations created with container-grown plants (Paperpot) and natural stands including young (7–9 year old) and older (19–24
year old) trees. Trees were measured with regards to distribution of roots, root deformation, stability, stem straightness
and wood properties in stumps. Root distribution was most uniform for naturally regenerated trees. Older trees generally showed
a better root distribution than young trees. The young planted trees displayed a high frequency of severely spiralled root
systems, while only a few of the older trees had spiralled root systems. No severe root deformations were observed on naturally
regenerated trees. Naturally regenerated trees were more stable than those which had been planted. Differences in bending
moment, when trees were pulled to an angle of 10°, were considerable between young planted and naturally regenerated trees,
but less pronounced for the older trees. Young planted trees had the highest frequency of severely crooked stem bases, while
naturally regenerated trees had the straightest mode of growth. Tensile strength in peripheral wood samples of the stumps
was substantially lower for planted than for naturally regenerated trees. Strain values to breakage of wood samples, taken
from the root collar and the central- and peripheral part of the stump were lower for planted trees. The conclusions from
this study are that root distribution, tree stability and stem straightness of planted Paperpot-grown trees will improve after
a certain time and approach the state of naturally regenerated trees. As trees grow older, early established crooked stem
bases will be compensated by radial growth and the tree will appear straighter. Inside the stem, however, problems may still
remain with abnormal fibre direction and compression wood together with inferior root strength due to fibre disturbances as
a result of spiralled roots.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献