汕头市松材线虫病的防治

基于汕头市濠江区已发现松材线虫病疫情的实际情况,针对该病的防治特点,结合汕头市各辖区山林的实际情况,从判断、预防、治理三个方面提出相应的防治对策,为科学防控该病在我市的扩散危害提供参考。     

松材线虫rNDA-ITS1区分子检测与鉴定

利用两对松材线虫特异性引物，分别对来自日本、美国和葡萄牙的松材线虫虫样进行PCR检测，成功扩增出330bp和220bprDNA-ITS1区基因片段，该方法对松材线虫成虫或幼虫均能作出准确鉴定。     

基于链路可共享性的多播路由算法

基于链路可共享性,提出一个快速有效的时延约束多播路由算法SBMR.该算法首先计算各链路的可共享性,然后根据链路的可共享性,由大到小依次选择链路参与多播路由,最后由所选链路组成一棵低代价的多播树.实验结果表明,与多播路由KPP算法相比,本算法构建的多播树有72%比KPP算法构建的多播树更优,代价降低13%,启用的链路数减少9%,而且CPU时间减少15%.与多播路由DCSP算法相比,本算法以增加28%的CPU时间为代价,构建的82%的多播树比DCSP更优,代价降低15%,而且启用的链路数减少11%,达到了更好的链路共享.     

凸函数Steiner对称化的一个等价特征

函数Steiner对称化的经典定义是根据函数水平集的Steiner对称化以及函数的分层表示定义的.给出了强制凸函数Steiner对称化的一个解析表达式,它是经典Steiner对称化的一个等价特征.这个新的定义不依赖于函数水平集的Steiner对称化,而是将定义转化为一维的类似抛物线函数的Steiner对称化,这更有助于函数不等式的证明.函数的Blaschke-Santalo不等式是一个重要的函数形式的仿射等周不等式,它的几何背景是凸体的BlaschkeSantalo不等式.首先利用Steiner对称化的新的定义,证明了对于任意的强制凸函数经过一次Steiner对称化后积分值变小了;然后利用Prekopa-Leindler不等式证明了径向函数的Blaschke-Santalo不等式.由于任何凸函数经过不断的Steiner对称化总可以在Lp范数意义下收敛于它的对称递减重排,而对称递减重排即为径向函数,因此证明了函数形式的Blaschke-Santalo不等式.     

双稠哌啶类生物碱分子结构与杀线活性间关系

使用培养基法和棉球法测定了苦豆碱、野靛碱、甲基野靛碱、苦参碱对松材线虫的杀线活性。两种生测方法测得的结果一致,表明苦豆碱的杀线活性最强,其ｌｏｇ（１／ＩＤ５０）（ｍｏｌ／棉球）＝８．６７,与文献中用同样方法测定的对松材线虫杀线活性的其它７种双稠哌啶类生物碱的杀线活性相比较,它也是最强。本文提出了双稠哌啶类生物碱对松材线虫的杀线活性强弱主要受其分子结构中官能团对的类型及其中的官能团的类型控制的假说。根据这一假说,推测了具高杀线活性的生物碱的分子结构。     

菊花叶枯线虫病对菊花不同品种的危害分析

菊花叶枯线虫病Aphelenchoides ritzemabosi(Schwartz)Steiner是菊花的重要病害。通过对带有菊花线虫泥土的盆栽菊花连续观察，证实不同品种菊花感病性不同，大叶型菊花感病较轻，中、小型菊花感病较重，经方差分析，差异极显著。此外，有菊花褐斑病与叶枯线虫病同株发生现象。     

花绒坚甲的生物学和生态学特性研究初报

花绒坚甲是松褐天牛的重要天敌。本文报道了广东地区寄生在松褐天牛上的花绒坚甲的形态特征、生物学和生态学特性,并提出了关于保护利用的一些看法。     

贵阳市花溪区松材线虫病入侵风险评估

依据松材线虫病Bursaphelenchus xylophilus(Steiner et Buhrer)的适生性、抗逆性和适应性分析,从该病的分布状况、潜在危险性和寄主经济重要性等方面,对其进行定量风险评估。结果表明：贵阳市花溪区为松材线虫病的生态适生区和易发流行区,风险值为2.57,松材线虫病传入花溪区的风险为特别危险。     

Impact of the invasion of pinewood nematode and the following different removal disturbance intensities on the plant diversity of Masson pine community

Reported in this paper are our findings of the study on changes in species diversity of different Masson pine communities after the invasion of Bursaphelenchus xylophilus (Steiner and Buhren) Nickle and subsequent and different removal disturbance management approaches. Based on the results, the species diversity indices for the arbor layers of the different communities can be arranged in the following order (from high to low): 1) broad-leaved stand after the removal of all infected pine trees in the pure pine stand in Fuyang; 2) lightly infected Masson pine and Schima superba mixed stand in Fuyang; 3) uninfected stand mixture of Masson pine and Castanopsis fargesii as a control; 4) lightly infested pure Masson pine stand in Fuyang; 5) Quercus variables stand formed following the selective removal of infected pine trees from a mixed Masson pine and Q. variables stand in Zhoushan Islands; 6) pure young Masson pine stand formed following the removal of all infected pine trees from a pure Masson pine stand; 7) pure Liquidambar formosana stand after the removal of infected pine trees from a pure pine stand in Zhoushan Islands; 8) a mixed stand consisting of Pinus thunbergii and the Masson pine in Zhoushan Island; and 9) moderately infected Masson pine stand in Zhoushan Islands. All the three diversity indices (R ₀ = richness, H′ = Shannon-Wiener index, and E = evenness) for the shrub layer did not show any significant differences among the various communities except for the pure pine stand in Zhoushan Island, which had the lowest diversity. The three indices for the herb layer of the pure young Masson pine, Q. variables stand, and L. formosana stand were higher than that of other stands. The integrated analysis showed that the Masson pine forest in different geographical situations and extent of damage had distinct disparity, just as in different disturbance degrees and restoring manners. We created the “index of disturbing intensity of stump and fallen woods” (IDISFW) to represent the degree of disturbance of tree removal to plant diversity. We found that the relationship between the species diversity index and the IDISFW shows both a lower and higher degree of removal disturbance that follows the “mid-altitude bulge” theory. Specifically, both excessive and insufficient removal of infected trees will cause a decline of plant species diversity to a certain degree. Covariance analysis indicated that different IDISFW had no significant effects on the species diversity of the arbor layer, but had different impacts on that of the shrub and herb layers, and therefore can be used to assess changes in species diversity of different Masson pine communities after the invasion of pine wood nematode. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(7): 1,157–1,163 [译自: 应用生态学报]     

松材线虫病流行与松毛虫危害关系的研究

研究表明 :在松材线虫病发生区 ,其病害的扩展、流行与马尾松毛虫危害有着密切的关系。当年受马尾松毛虫危害的松林 ,枯死松树数量平均为 77 879株 /hm2 ,比未受松毛虫危害的松林 (对照 ) 17 2 73株 /hm2 ,多 35 1% ;次年 ,前者平均枯死松树达 2 0 4 8株 /hm2 ,为对照 2 89株 /hm2 的 6 0 8%。松毛虫危害加速松材线虫病流行的原因是 ,松毛虫危害松树 ,削弱树势 ;弱势的松树招引松墨天牛侵入并增殖加快松树死亡 ;次年大量天牛从“松毛虫危害松木”上羽化 ,侵染健康松林 ,导致松材线虫病进一步扩散和流行。由此认为松毛虫危害是促使松材线虫病流行的重要因子 ,防治松毛虫是控制松材线虫病流行的重要环节之一