标准拥挤度在黄龙病田间分布格局评价的应用

Application of Standard Crowding Degree on Field Distribution Evaluation of Citrus Huanglongbing

以样方容量m为参照系对平均拥挤度M^(*)算法进行无量纲化修正M^(*)=[∑x_(i)(x_(i)-1)]/[(m-1)·∑x_(i)],称标准拥挤度(Standard crowding,M^(*)),并依此研究柑橘黄龙病(HLB)病株田间分布格局,为田间巡检柑橘黄龙病植株提供导向性建议。同时定义:个体无间隔相邻为聚集,个体间隔1个体位相邻为半聚集;并由无限单样方的最大非聚集与最大非半聚集个体数推演M^(*)≥0.1111、0.25、0.50为绝对半聚集、绝对聚集、半饱和聚集。结果表明,M^(*)与柑橘黄龙病发病率HLB%极显著正相关r=0.8041、P=1.9E-5、n=20;HLB%由初发期的1.25%至盛发期的47.97%,其病株田间分布格局依次由非聚集、半聚集,逐步向聚集、半饱和聚集发展,即外源远距入侵呈非聚集随机分布而内源侵染则呈聚集分布。回归模型M^(*)=0.0872×Sqrt(HLB%),F=220.20、P=6.6E-12、n=20,当HLB%>1.62%、8.22%时,病树分布格局呈半聚集、聚集态势,可作为田间调查评估参考。HLB由初始期至盛发期、衰亡期,病树田间分布格局逐渐由非聚集、半聚集,向聚集、半饱和聚集过渡。标准拥挤度M^(*)可作为生物聚集度评价的共享范式。

Taking the sample volume m as the reference system,the algorithm of average crowding degree M^(*)was modified dimensionlessly,M^(*)=[∑x_(i)(x_(i)-1)]/[(m-1)·∑x_(i)],which was called as standard crowding degree(M^(*)).Based on this,the field distribution pattern of citrus Huanglongbing plants was studied to provide guidance suggestions for field inspection of citrus Huanglongbing plants.At the same time,it is defined as aggregation if individuals are adjacent without interval,and semi aggregation if individuals are adjacent with one position interval.It is deduced that M^(*)≥0.1111,0.25 and 0.50 are absolute semi aggregation,absolute aggregation and semi saturated aggregation from the max_(i)mum number of non aggregation and non semi aggregation individuals of infinite single quadrat.The results showed that,M^(*)was significantly positively correlated with the incidence rate of HLB% with r=0.8041,P=1.9E-5 and n=20;HLB% changed from 1.25% at the initial stage to 47.97% at the peak stage.The distribution pattern of diseased plants in the field changes from non-aggregated,semi-aggregated,and gradually develops towards aggregation and semi-saturated aggregation.Random distribution and endogenous infections are clustered distribution,that is,the distant invasion of exogenous was random distribution,while the endogenous infection was aggregation distribution.The best regression model of M^(*)and HLB% is M^(*)=0.0872×Sqrt(HLB%),F=220.20,P=6.6E-12,n=20,when HLB%>1.62% and 8.22%,the distribution pattern of diseased trees is semi-aggregation and aggregation,which can be used as a reference for field investigation and evaluation.From the initial stage to the peak stage and the decline stage of HLB,the field distribution pattern of diseased trees gradually changed from non-aggregation and semi-aggregation to aggregation and semi-saturation aggregation.The Standard crowding degree(M^(*))can be used as a shared paradigm for evaluating biological aggregation degree.