陕西卫矛夏季嫁接试验

试验表明:陕西卫矛用丝绵木为砧木,在生长季节截头插皮枝接比芽接成活率高出24%,冠形好,成型更快,是一种高效的好方法.     

乌桕根皮醇提物萃取部位抗猪大肠杆菌活性分析

[目的]探讨乌桕根皮醇提物各部位对猪大肠杆菌4种血清型的抗菌活性。[方法]用95%乙醇80℃回流提取乌桕根皮,将醇提液浓缩后依次用石油醚、乙酸乙酯和正丁醇萃取,最后得到萃余的水相,测试各部位的抗菌活性。[结果]醇提物的石油醚部位、正丁醇部位和水部位没有抑制作用,乙酸乙酯部位对血清型K88F、41和987P具有抑制效果,而对血清型K99无效。因此,用中药材防治猪大肠杆菌疾病时,应该考虑到血清型差异。[结论]乌桕根皮提取物可以在一定程度上防治大肠杆菌引起的猪病。     

Cavity and bark nesting bird response to partial cutting in Northern conifer forests

We investigated whether partial cutting used to mimic small-scale natural disturbances could maintain cavity and bark nesting breeding birds. We assessed changes in the relative abundance of cavity nesting birds in two intensities of partial cutting, compared to uncut and clearcut stands, 9 years post-treatment. We then examined the relationship between forest structure and nesting abundance (stand scale) and compared characteristics of used nest and forage trees to unused trees (tree scale). The relative abundance of most species was highest in either heavy removal or light removal treatments 9 years post-harvest. Brown creepers were most abundant in uncut, and red-breasted sapsuckers were most abundant in clearcut and heavy removal treatments. The proportion of deciduous trees and the density of dead trees were the best predictors of nest abundance. Individual nest tree use was predicted by the presence of large deciduous trees with broken tops and early to advanced stages of decay. Forage tree use was predicted by the presence of large conifer trees in advanced stages of decay. To maintain breeding habitat for cavity nesters, we suggest that forest managers retain the specific structural attributes required for nesting, but also the diverse forest conditions required for foraging.     

Protection of spruce from colonization by the bark beetle, Ips perturbatus, in Alaska

Field bioassays were conducted in south-central Alaska in a stand of Lutz spruce, Picea × lutzii, to determine whether a semiochemical interruptant (verbenone and trans-conophthorin) and/or a defense-inducing plant hormone (methyl jasmonate, MJ) could be used to protect individual standing trees from bark beetle attack. During two experiments (initiated in May 2004 and 2005, respectively), attacks by Ips perturbatus on standing trees were induced by using a three-component aggregation pheromone (ipsenol, cis-verbenol, and ipsdienol) and prevented by using the interruptant. In 2005, treatments from 2004 were repeated and additional treatments were evaluated by using MJ spray or injection with and without the interruptant. Aggregation began before 3 or 7 June, and attack density was monitored through 3 or 16 August. During both years, tree mortality caused by I. perturbatus was recorded twice (in August, and in May of the following year). In both experiments, attack density was greatest on trees baited with the three-component attractive pheromone, but was significantly reduced by addition of the semiochemical interruptant to trees baited with the attractant. There were no significant differences in attack density between attractant + interruptant-treated trees and unbaited trees. In 2004, mortality was highest among attractant-baited trees, whereas addition of the interruptant significantly reduced the level of initial (10 week post-treatment) and final (54 week post-treatment) mortality. In 2005, no significant reduction in attack density occurred on trees baited with the attractant when MJ was sprayed or injected. The highest initial (10.6 week post-treatment) and final (49.4 week post-treatment) mortality was observed among trees that had been injected with MJ and baited with the attractant. Mortality at the final assessment was significantly lower in all other treatment groups. As in 2004, addition of the interruptant to attractant-baited trees significantly reduced the level of final mortality compared to attractant-baited trees. MJ was not attractive or interruptive to I. perturbatus or associated bark beetles in a flight trapping study. However, MJ-treated trees (sprayed or injected) exuded copious amounts of resin on the bark surface. Anatomical analyses of felled trees from four treatment groups [Tween (solvent)-sprayed, MJ-sprayed, Tween-injected, and MJ-injected + attractant baited] showed that treatment with MJ increased the number and size of resin ducts produced following treatment. These analyses also revealed a reduction in radial growth in MJ-treated trees. Our results show that during both years, treatment with a simple, two-component interruptant system of verbenone and trans-conophthorin significantly reduced I. perturbatus attack density and tree mortality on attractant-baited trees and provided a full year of protection from bark beetle attack.     

Risk rating for mountain pine beetle infestation of lodgepole pine forests over large areas with ordinal regression modelling

The mountain pine beetle Dendroctonus ponderosae Hopkins is endemic to lodgepole pine, Pinus contorta var. latifolia Engelmann, forests in western Canada. However, the current beetle epidemic in this area highlights the challenges faced by forest managers tasked with prioritizing stands for mitigation activities such as salvage harvesting and direct control methods. In western Canada, the operational risk rating system for mountain pine beetle is based on biological knowledge gained from a rich legacy of stand-scale field studies. Due to the large spatial (millions of hectares affected) and temporal (over 10 years) extents of the current epidemic, new research into large-area mountain pine beetle processes has revealed further insights into the landscape-scale characteristics of beetle infested forests. In this paper, we evaluated the potential for this new knowledge to augment an established system for rating the short-term risk of tree mortality in a stand due to mountain pine beetle. New variables explored for utility in risk rating include direct shortwave radiation, site index, diameter at breast height, the temporal trends in local beetle populations, Biogeoclimatic Ecosystem Classification and beetle–host interaction variables. Proportional odds ordinal regression was used to develop a model for the Vanderhoof Forest District in west-central British Columbia. Prediction on independent data was assessed with the area under the receiver operator curve (AUC), indicating good discriminatory power (AUC = 0.84) for predicting levels of mountain pine beetle-caused pine mortality.     

小蠹虫与真菌共生关系的研究进展

从小蠹虫与真菌共生的类型、小蠹虫贮菌器结构、小蠹虫与真菌共生机制和协同进化等方面对小蠹虫与真菌关系的研究进展进行了评述,并讨论了小蠹虫与真菌关系的发展趋势.     

黑荆树皮单宁不同级分对水解酶的抑制作用

通过对黑荆树皮单宁进行醇沉纯化和溶剂萃取分级,可得到分子量分布范围不同的单宁级分。各级分对5种水解酶均表现出不同程度的抑制作用,具有一定的选择性。其抑制能力与抑制剂常数Ki值有关,分子量大的单宁级分,Ki值小,对酶活性的抑制作用大,同时,证明了黑荆树皮单宁对纤维素酶的抑制作用属于非竞争性抑制。     

浙江莫干山的叶甲

本文记述浙江莫干山鞘翅目叶甲科叶甲亚科昆虫计8属14种。     

环境因子对苹果粗皮病发生的影响

苹果粗皮病是苹果树严重的生理病害。为探讨苹果粗皮病致病机理,通过田间采样、土壤理化特性与气候因子分析,研究土壤等环境因子与苹果粗皮病发生的关系。结果表明,苹果粗皮病在棕壤土和滨海潮土上均可发生。土壤pH高低与苹果粗皮病的发生相关,土壤pH越低,土壤有效锰含量越高,苹果粗皮病发病程度越重,但土壤pH不是苹果粗皮病主要致病因子。不同感病地点的土壤有效锰含量相差悬殊,在0～80cm范围内,牟平最高锰含量为29.30mg/kg,而栖霞最低为57.39mg/kg,最高达114.43mg/kg,说明土壤有效锰含量不是苹果粗皮病发生的唯一因子,但发病率栖霞要高于牟平。土壤有效锰铁呈负相关性,锰铁比增大,可引起树体对锰的过量吸收,苹果粗皮病发生程度加重。因此,苹果粗皮病发生是土壤锰含量、锰铁比、土壤pH、降雨量等环境因子综合作用的结果。     

Monitoring of Bark and Wood-Boring Beetles in France after the December 1999 Storms

After the December 1999 storms, two networks were set up over 2 years (2000 and 2001) to assess the scale and type of insect colonisation on storm damaged trees and to interpret these events for the future. The Level 1 network, was a large-scale survey that covered the entire storm area and provided qualitative observations on its 898 plots in which every major tree species was assessed. The Level 2 network, was a regional survey set up only in two regions: the 'Landes' region and the Northeast of France. The observations were intensive and quantitative, devoted only to maritime pine in the 'Landes' region and to Norway spruce in the Northeast of France. The Level 1 network indicated that less than 40% of the storm damaged trees were colonised by bark beetles in September 2000. No attacks were observed on standing trees in 2000 but many occurred during 2001 in spruce and maritime pine stands. The Level 2 network in the Vosges mountains showed a late colonisation in October and November 2000. The emerging population of Ips typographus on attacked trees reached 25 000–30 000 insects/m³. This huge population combined with the low rate of parasitism in 2001 leads to the expectation of increasing damage in spruce stands next year.