关键词: 变化特征, 变化特征, 初（终）霜日, 无霜期, 关中西部

Abstract: [Objective] In order to understand the individual morphology and component characteristics of annual plants in sandy area, [Method] by methods of sample plot investigation, laboratory bioassay and statistical analysis, the individual morphological characteristics and component characteristics of typical annual plant Agriophyllum squarrosum in Minqin sandy area were observed and studied, and the relationship between component biomass and plant height was analyzed. [Result] The results show that the variation coefficient of the individual morphological indices of Agriophyllum squarrosum were greater, especially the variation coefficient of root length and lateral root number were greater than 50%, which showed that Agriophyllum squarrosum had good adaptability and adjustment ability to growth environment. The dry weight of individual biomass of Agriophyllum squarrosum was between 24.55 g and 138.09 g. The order of the dry weight biomass distribution of each component was the ear(36.51±26.07g) > branch(31.00±20.26g) > leaf (24.09±12.97g)> root(6.63±3.75g), and the biomass of Agriophyllum squarrosum growth will be distributed as much as possible to the reproductive component. The body_"s moisture content of Agriophyllum squarrosum individual was 70.89±1.61%, the moisture content of the component was between 64.91% and 74.97%, and there were differences in moisture content of different components. The biomass allocation of Agriophyllum squarrosum components increased with the increase of plant height in a power function, which was the expression of Agriophyllum squarrosum individual growth and development ability regulation strategy. [Conclusion] The differences in the adaptability of the Agriophyllum squarrosum to the growth environment resulted in the difference of individual morphological characteristics, and the biomass was allocated to the reproductive component to ensure the continuation of species as much as possible. The biomass allocation value of each component of Agriophyllum squarrosum can be measured by simulation model of plant height, which provides the basis for the study of annual plant in desert ecosystem.