云南切梢小蠹与横坑切梢小蠹蛀梢期的竞争研究

2000年5月至2001年5月,研究了云南切梢小蠹与横坑切梢小蠹蛀梢期的种间竞争,比较了2种松小蠹在其寄主云南松树冠的垂直分布规律.结果表明,不同月份2种松小蠹在云南松树冠的垂直分布的存在差异,并随着月份的变动而发生变化.横坑切梢小蠹多危害较细的松梢,而云南切梢小蠹多危害较粗大的松梢.2种松小蠹的其它蛀梢习性(危害梢的年龄、攻击部位、蛀道长度等)文中也进行了比较.结论,云南切梢小蠹对云南松树梢的攻击能力强于横坑切梢小蠹.     

松纵坑切梢小蠹及其防治

本文详细介绍了松纵坑切梢小蠹的形态特征、生活习性以及防治措施，对以后防治松纵切梢小蠹有一定的指导意义。     

云南切梢小蠹和横坑切梢小蠹对寄主繁殖部位的选择试验(英文)

在室内条件下,对繁殖期云南切梢小蠹和横坑切梢小蠹的竞争展开了研究。在养虫笼中放入来源同株云南松的2根木段,同时放入2种小蠹,分别放入1种小蠹,观察小蠹对其繁殖材料云南松木段的选择。试验表明,横坑切梢小蠹喜在树皮厚的木段上繁殖,即云南松树干的下部,而云南切梢小蠹喜在树皮薄的木段上繁殖,即云南松树干的上部。从产卵到新成虫羽化,云南切梢小蠹的历期明显短于横坑切梢小蠹,分别为86～89 d和120～125 d。结论:在中国云南,云南切梢小蠹对云南松的攻击能力强于横坑切梢小蠹,后者更具次期性害虫特点。     

松纵坑切梢小蠹和横坑切梢小蠹在云南松蠹害木上的分布

经对36株蠹害木作解析,发现纵坑、横坑切梢小蠹虫在云南松蠹害木上的虫种分布、虫口密度,因危害程度——枯萎木、濒死木和树木部位不同而异。林内衰弱的松树先受纵坑切梢小蠹的侵害,导致松树成片枯死主要是后来侵害的横坑切梢小蠹虫。     

一种区分三种切梢小蠹性别的新方法

云南切梢小蠹;Tomicus yunnanensis;,横坑切梢小蠹;T.minor;和短毛切梢小蠹;T.brevipilosus;是云南松的重要害虫。利用体视显微镜和扫描电镜,作者对上述3种切梢小蠹雌雄虫腹部末端可见背板(即雌虫第7节背板和雄虫第8节背板)的长和宽分别观察、测量和比较,研究快速准确区分两性成虫的新方法。结果表明:在两性之间,长度和宽度均存在明显差异。这3种小蠹雌虫腹部末端背板呈半圆形、宽大,长×宽分别为(590±17) μm×(827±31)μm,(619±25) μm×(780±16) μm和(594±29) μm×(815±21) μm; 而雄虫腹部末端可见背板近似长方形、窄小,长×宽分别为 (365±30) μm×(608±24) μm,(237±41) μm×(580±33) μm和(296±36) μm×(593±25) μm。该方法能在数秒内将雌雄虫分开,且不会伤害活虫,能最大限度地保留标本的完整性。     

松纵坑切梢小蠹自然种群死亡原因分析

利用多重降解生命表来分析松纵坑切梢小蠹自然种群的死亡原因，是一种新方法，本文利用云南省昆明地区松纵坑切梢小囊自然种群生命表的资料。分析其死亡原因，发现该地区松纵切梢小蠹自然种群５２．７９％的死亡率出现于卵期，幼虫期和蛹分别为１８．０６％，２２．０３％，１２．７０％；特别是幼虫期和卵期死亡率最高，其中３４．８６％的种群死亡为捕食性天敌所致。其捕食率分别为１２．６４％和１２．５８％，因此，认为捕食是幼     

纵坑切梢小蠹种群变动及危害规律研究

以弥勒县的新哨和石林县的长湖受蠹害严重的林区的1000株云南松为定期观察样树,分别不同树木长势级别和受害木等级进行调查统计分析．结果表明,纵坑切梢小蠹在云南1年发生1代,且存在姐妹代现象,姐代种群占79．3％．妹代种群占18．6％．纵坑切梢小蠹对云南松的攻击有很强的选择性,优先攻击长势差的衰弱木．蠹害的危害从零星和簇状分布开始向大片状发展,待树木衰弱后进行蛀干危害．对蠹害木数量变化规律分析结果表明,树木受害越重,转化为枯死木的比例越高,当树木受害等级达4级以上时,树木很难再恢复生长．     

云南省纵坑切梢小蠹治理新技术

在按照云南省纵坑切梢小蠹治理新思路成功防治2万hm^2松林的基础上,总结出与纵坑切梢小蠹治理新思路相配套的新技术,对云南省纵坑切梢小蠹的治理提出了可行性技术要求。     

松纵坑切梢小蠹自然种群死亡原因分析

利用多重降解生命表来分析松纵坑切梢小蠹自然种群的死亡原因，是一种新方法。本文利用云南省昆明地区松纵坑切梢小蠹自然种群生命表的资料，分析其死亡原因。发现该地区松纵坑切梢小蠹自然种群５２．７９％的死亡率出现于卵期、幼虫期和蛹期，分别为１８．０６％、２２．０３％、１２．７０％；特别是幼虫期和卵期死亡率最高，其中３４．８６％的种群死亡为捕食性天敌所致。其捕食率分别为１２．６４％和１２．５８％，因此，认为捕食是幼虫期及卵期控制种群数量的关键因子之一。对该害虫进行综合防治时，应重点加强对捕食性天敌的保护和利用。     

云南松纵坑切梢小蠹种群生态研究现状

通过对现有文献的考察 ,从影响云南松纵坑切梢小蠹的危害因素 ,小蠹的生活史、蛀干蛀梢期、种群动态、生命表、空间分布格局以及虫情预测预报等方面阐述了云南松纵坑切梢小蠹种群生态的研究进展状况。以此对松小蠹的综合治理提出几点建议     

蛀干期3种切梢小蠹不同种群数量及其在树干分布研究

切梢小蠹是危害云南松的主要害虫种类之一,发生在云南地区的横坑切梢小蠹、云南切梢小蠹和短毛切梢小蠹,已造成大量松树的死亡。通过研究蛀干期3种切梢小蠹在云南松树干的种群数量及空间分布,以掌握其分布和危害特点,将蛀干期刚被入侵为害的云南松树干截成长50 cm的木段,解剖并记录每段木段上的切梢小蠹种类和数量。结果表明,玉溪市采集到横坑切梢小蠹的数量占总数量的89.5%,整个树干均有分布,云南切梢小蠹数量占总数量的10.5%,主要分布在树干的中上部。建水县采集到横坑切梢小蠹的数量占比为58.5%,分布于树干的中下部,云南切梢小蠹的数量占比为41.5%,且在整个树干均有分布。安宁市采集到横坑切梢小蠹、云南切梢小蠹和短毛切梢小蠹的数量占比分别为31.6%、31.8%和36.6%,主要分布于树干的中下部、中上部及整个树干。3个地区的3种切梢小蠹,在树干相同高度分布的同种切梢小蠹,其雌虫、雄虫在数量上无显著差异。云南地区蛀干期3种切梢小蠹种群数量在树干分布情况随着地区不同而不同,在云南松树干的空间分布与其发生数量有着密切关系,这为不同地区针对不同切梢小蠹种类而制定不同的防治措施提供了参考。     

Generalized allometric volume and biomass equations for some tree species in Europe

Since biomass is one of the key variables in ecosystem studies, widespread effort has aimed to facilitating its estimation. Numerous stand-specific volume and biomass equations are available, but these cannot be used for scaling up biomass to the regional level where several age-classes and structural types of stands coexist. Therefore simplified generalized volume and biomass equations are needed. In the present study, generalized biomass and volume regression equations were developed for the main tree species in Europe. These equations were based on data compiled from several published studies and are syntheses of the published equations. The results show that these generalized equations explain 64–99% of the variation in values predicted by the original published equations, with higher values for stem than for crown components.

Over-expression of Tryptophan Decarboxylase Gene in Poplar and its Possible Role in Resistance Against Malacosoma disstria

Amines and their derivatives are known to influence insect behavior involved in feeding and reproduction. In order to examine the feasibility of improving the resistance of poplar to insect pests by the introduction of a plant-derived amine-generating transgene, explants from the hybrid poplar clone ‘INRA 717 1B4’ (P. tremula ×P. albo) were transformed with a Camptotheca acuminata tryptophan decarboxylase (TDC, EC 4.1.1.28) cDNA driven by the CaMV 35S promoter. The enzyme TDC catalyzes the decarboxylation of tryptophan to tryptamine, which, in addition to being a bioactive amine itself, is known to act as a precursor of various other indole derivatives. Putative transgenic lines were confirmed by PCR for the TDC1 gene sequence and by the expression analysis of the transgene mRNA and encoded protein. No visible phenotypic changes were associated with ectopic TDC1 expression. Chemical and radiotracer analyses of the transgenic plants revealed tryptamine accumulation as high as 4 mM in leaf tissue, and suggested that the tryptamine produced by ectopically expressed TDC was not further metabolized. Insect bioassays with the TDC transgenic plants showed that the tryptamine accumulation was consistently associated with adverse effects on feeding potential and physiology of Malacosoma disstria (forest tent caterpillar).     

Selection of efficient VA mycorrhizal fungi for Casuarina equisetifolia—second screening

An investigation was carried out to screen and select efficient vesicular arbuscular mycorrhizal (VAM) fungi for inoculating the forest tree species, Casuarina equisetifolia. The seedlings were inoculated with 10 different VAM fungi, obtained from various sources. Inoculated seedlings generally had greater plant height, stem girth, biomass and P content than uninoculated plants. They also had more mycorrhizal root colonization and spore numbers in root zone soil. C. equisetifolia seedlings responded best (in biomass) to inoculation with Glomus mosseae (Nicolson and Gerdemann) Gerdemann and Trappe, closely followed by Acaulospora laevis Gerdemann and Trappe and G. fasciculatum (Thaxter Sensu Gerdemann) Gerdemann and Trappe; all the three being statistically on par with each other.     

沉香属植物繁殖研究进展

沉香属植物为瑞香科名贵木材树种,我国有土沉香（又名白木香）和云南沉香2种,其中土沉香是我国生产沉香的重要植物资源。由于沉香的用途极其广泛,其野生资源已日趋枯竭,出现供不应求的局面。文中从种子繁殖、扦插繁殖、嫁接繁殖、组培繁殖等方面综述了土沉香等沉香属植物繁殖技术的研究进展,并对沉香属植物繁殖的研究重点进行了展望,以期为沉香属植物高效繁育优质种苗提供参考,并有利于野生资源保护和可持续利用。     

Antimicrobial activities of Indian Berberis species

The antimicrobial activity of hydroalcoholic extracts of four Berberis species viz. Berberis aristata, Berberis asiatica, Berberis chitria and Berberis lycium were tested against eleven bacterial and eight fungal strains. B. aristata root extract gave low MICs values against Bacillus cereus, Escherichia coli, Staphylococcus aureus and Aspergillus flavus while stem extract against B. cereus and Streptococcus pneumoniae.     

Cloning of erect,thornless, non-browsed nitrogen fixing trees of Haiti's principal fuelwood species (Prosopis juliflora)

A progeny trial in Haiti compared 70 open-pollinated families ofProsopis representing seed sources from Haiti, Peru, Chile, Argentina and southwestern US. At the end of 4 years growth, the tallest 6 families were of Peruvian origin. Some of these Peruvian trees (probablyP. juliflora) were thornless, had erect habit and were non-browsed by goats, unlike other thornlessProsopis alba families from South America. Scions from the 5 tallest spineless and most erect trees were transported from Haiti to Texas A&I University where they were successfully grafted ontoP. alba rootstock. These scions should have great potential for grafting onto existing weedyProsopis and for grafting onto rootstock previously shown to tolerate salinities of seawater and pH values of 10.3.     

The root-knot nematode problem in sesbania fallows and scope for managing it in western Kenya

Sesbania (Sesbania sesban), which is promoted as a short-duration-fallow species in eastern and southern Africa, is an alternative host to root-knot nematode (Meloidogyne spp.). Therefore, it is important to know the extent of sesbania infection by the nematode on farms and its effects to crops grown in rotation with sesbania. A survey of 14 farms in western Kenya indicated that sesbania was infected by root-knot nematode in all the farms. The potential to build up the nematode population was much greater on farms where maize (Zea mays) was previously intercropped with a susceptible bean (Phaseolus vulgaris). Screening of 30 single plant accessions of four sesbania provenances (Kakamega, Siaya, Kisumu, and Kisii) from western Kenya in pots indicated limited scope for selecting material resistant to the nematode. All four provenances were infested by the nematode, and they increased its population in soil and root. A rangewide collection of sesbania germplasm needs to be screened to determine the scope of finding nematode-resistant material. Transplanted seedlings produced in heat-sterilized, nematode-free soil showed less nematode infection than direct-seeded plants. However, both direct seeding and transplanting seemed to increase nematode population similarly. A number of Crotalaria spp. that were found resistant to nematodes can be considered as alternatives to sesbania-planted fallows, but further field-scale testing is necessary to select appropriate species based on biomass production. Among other species suitable for short-duration fallows, only pigeonpea (Cajanus cajan) and senna (Senna siamea) showed promise. Species such as neem (Azadirachta indica), casuarina (Casuarina junghuhniana), and grevillea (Grevillea robusta) that are suitable for boundary plantings were free from the root-knot nematode.This revised version was published online in November 2005 with corrections to the Cover Date.