Analysis of pine-wilt susceptibility-enchancing effect of co-occuring trees on pine trees

为研究赤杨化感物质对松树感病性的影响，用赤杨和日本木风干叶片和嫩枝的水提液培养黑松，将其稀释成1、10、10、10倍，接种松材线虫，一周后接种黑松，赤杨浸提液对松树感病性的影响大于日本木浸提液，接种后的死亡率高于日本木浸提液。结果表明，赤杨浸提液对松树感病性的影响大于日本木浸提液，而日本木浸提液对松树感病性的影响大于日本木浸提液。赤杨浸提液对松树感病性的影响大于日本木浸提液，而日本木浸提液对松树感病性的影响大于日本木浸提液。赤杨浸提液对松树感病性的影响大于日本木浸提液对松树感病性的影响。赤杨浸提液对松树感病性的影响大于日本木浸提液对松树感<-1><-2>病性的<-3>影响为了<-3>鉴定西兰花的化感物质，对西兰花叶片的甲醇提取物进行了分级分离，用i-BuOH提取的水相部分在500和1，000 ppm浓度下抑制莴苣根的生长，并使根的末端部分变成褐色。~ 3C-NMR谱和生物测定结果表明，D-（+）-儿茶素是一种化感物质，其对根生长的抑制作用是由儿茶素本身引起的，而不是由儿茶素在根中的代谢产物引起的。松墨天牛成虫在室外笼中饲养，笼中装有盆栽的亚洲松墨天牛或日本木。成年雌虫的存活率和繁殖力无显著差异。

To determine the effect of allelochemicals of Alnus sieboldiana on the susceptibility of Pinus trees to pine wilt disease.P.thunbergii seedings were cultured with the solution which was extracted from air-dried leaves and twigs of A.sieboldiana and Eurya japonica with water.The solution used was diluted at 1,10^<-1>,10^<-2> or 10^<-3>.Bursaphelenchus xylophilus was inoculated on seedlings a week later.Mortality from pine wilt was higher on A.sieboldiana extract than on E.japonica at 10^<-3>.To identify the allelochemicals of A.sieboldiana, methanol extract of the leaves was fractionated.Aqueous fraction extracted with i-BuOH inhibited the root growth of lettuce and made a terminal part of root brown at concentrations of 500 and 1,000 ppm.^3C-NMR spectrum and bioassay showed that D-(+)-catechin was an allelochemical.The inhibitory effect on root growth was induced by catechin itself and not by metabolites of catechin by root.To clarify the effect of A.sieboldiana on the reproduction of insert vector of pine wilt, Monochamus alternatus adults were raised in outdoor cages containing A.sieboldiana or Eurya japonica potted.Cages excluding both tree species were served as control.There were no difference among adult females in survivorship and fecundity.