白背飞虱体内金属元素的含量动态及模拟分析

Dynamics and simulation modeling of the content of metal elements in Sogatella furcifera Horváth (Homoptera, Delphacidae)

为明确金属元素在白背飞虱Sogatella furcifera(Horváth)体内的分布及其含量动态,将白背飞虱长翅成虫在实验室中用超纯水分别饲养0,24,48,96h后测量其体重变化;并用电感耦合等离子体质谱(inductively coupledplasma mass spectrometry,ICP-MS)检测各个处理虫体内12种金属元素(Cu,Zn,Cd,Mn,Ca,Fe,Na,As,U,Mg,K和Pb)的含量。以白背飞虱整个体重(W)、有机体组织重量(O)、体内可排泄内容物重量(E)及可排泄内容物排出体外的速率(r)为参数,构建其体重变化的修正指数模型Wt=O+E(1-r)t。基于白背飞虱体内金属元素总含量(WCt)为有机体组织内含量(OC)和可排泄内容物中含量(EC)按两者百分率(OPt和EPt)加权之和,即WCt=OC·OPt+EC·EPt,分别估计白背飞虱体内组织和可排泄内容物中金属元素含量。模拟分析结果表明:Cu,Zn,Cd,Mn和Ca这5种元素在白背飞虱组织内的含量显著高于其可排泄内容物中的含量(P<0.05),表明这些金属元素可被昆虫有机体组织吸收、积累,并稳定地存在于昆虫的有机体组织之中。Fe,Na,As,U,Mg,K和Pb这7种元素在白背飞虱有机体组织内的含量与其可排泄内容物中的含量接近,其在有机体组织中和可排泄内容物中的分布差异不显著(P>0.05),以相对平衡状态存在于白背飞虱有机体组织和可排泄内容物中。该分析方法可能为其他小型和微型昆虫体内金属元素的分布、积累、排泄的研究提供借鉴。

To determine the distribution and dynamic excretion of metal elements, the test insects, adults of the Sogatella furcifera （Horváth） were subjected to feeding on deionized water for 0 h, 24 h, 48 h, and 96 h, respectively. The body weight changes were measured and the contents of twelve metal elements （Cu, Zn, Cd, Mn, Ca, Fe, Na, As, U, Mg, K and Pb） in S. furcifera were detected using ICP-MS technique. At the same time, we denote the entire body weight, the organic tissue weight, the weight of the intestinal contents and their excretion rate of S. furcifera by W, O, E and r, respectively. The body weight of S. furcifera at different time can be expressed by the modified exponent equation Wt=O＋E（1-r）t. Considering the content of a certain element in S. furcifera （WCt） should be the sum of the content of that element in the organic tissues （OC） and in the intestinal contents （EC）, the statistical model is WCt=OC·OPt＋EC·EPt, where OPt is the percentage of O to body weight at time t and EPt is the percentage of E. The results of simulation modeling showed that the contents of Cu, Zn, Cd, Mn and Ca are significantly higher in the organic tissues than those in the intestinal contents （P0.05）, suggesting that these elements can be absorbed or accumulated by organic tissues. The contents of seven elements （Fe, Na, As, U, Mg, K and Pb） have no significant difference between in the organic tissues and in the intestinal contents （P0.05）, suggesting that the contents of these elements in the organic tissues are balanced with those in the intestinal contents and their contents in insect body are not significantly changed. The simulation modeling method can provide reference to other studies involving metal distribution, accumulation and excretion in other small or micro-insects.