内蒙古典型草原生长季内不同植物生长动态的模拟

Simulation of growth dynamics of four plants in the typical steppe of Inner Mongolia in growing season

在内蒙古典型草原退化的羊草+大针茅(Leymus chinensis+Stipa grandis)群落中,选择不同退化阶段的优势植物羊草(Leymus chinensis)、大针茅(Stipa grandis)、冰草(Agropyron michnoi)、冷蒿(Artemisia frigida),采用Logistic模型分别对其一个生长季内的生长动态及其差异进行模拟和比较研究。主要研究内容和结果如下:①联系资源种群动态模型的一般形式,给出了个体生长模型的数学依据;②通过对Logistic模型进行求解和全面深入的分析,采用数学方法结合生态学理论,将植物生长划分为4个阶段,确定了速生期和突变点;③结合模型分析诠释了模型的物理意义;④对植物的可持续生长期从生态学的角度给出了时间概念上的定义及相应的解释,并由此对草地管理及可持续利用提出了保护建议;⑤通过拟合结果表明,4种植物生长均符合Logistic增长,拟合方程分别为:y=(0.200)/1+e^(2.032-0.060t),y=(1.205)/1+e^(2.608-0.0421t),,y= (0.156)/1+e^(1.858-0.040t),y= (3.177)/1+e^(2.770-0.077t),决定系数均在0.9以上,达到了显著性水平,保证了所求参数的有效性和可靠性;⑥由模型求出了植物的最大生长速度,从大到小依次排列为:冷蒿6.112×10-2(g/(株.d))>大针茅1.267×10-2(g/(株.d))>羊草2.995×10-3(g/(株.d))>冰草1.561×10-3(g/(株.d)),其中冷蒿的最大生长速度是羊草的20倍,大针茅的4.8倍,冰草的39倍;分属于3种不同生活型的羊草、大针茅、冷蒿在生长速度及相应的生长曲线上均存在较大差异,而作为同一生活型(life form)的不同植物相比较,羊草生长速度约为冰草的1.9倍,二者差异不大,在整个生长季内呈现明显相似的动态变化。

The growth dynamics of Leymus chinensis, Stipa grandis, Agropyron michnoi, Artemisia frigida in Leymus chinensis ＋ Stipa grandis degenerated community in the typical steppe of Inner Mongolia in one growing season were simulated and compared by the Logistic model. The results showed： ① Mathematical models of individual plants were determined according to the dynamic model of population. ② Growth of the plants was divided into four stages and the fast growing stages and the turning points of the four growing stages were also determined based on ecology theory and the Logistic model. ③Physical meaning of the model was explained. ④The periods of sustainable growth were determined and explained according to the ecology theory. Based on which the suggestions on grassland management and sustainable utilization were put forward. ⑤Growth of the four plants could be described with Logistic model. Simulation equations were ： y = 0.200/1＋e^2.032-0.060t,y=1.205/1＋e^2.608-0.042t,y=0.156/1＋e^1.858-0.040t,y=3.177/1＋e^2.770-0.077t respectively. The parameters in equations were effective and dependable, and all determinant coefficients exceeded 0.9. ⑥ Maximum growth rates were got through the model, it was A. frigida 6. 112 × 10^-2 （ g/（ plant, d） ） 〉 S. grandis 1. 267 × 10^-2 （ g/（ plant, d） ） 〉 L. chinensis 2. 995× 10^-3（g/（plant.d） ） 〉 A. michnoi 1. 561× 10^-3（g/（plant.d） ）. Comparing the maximum growth rate of four plants, the value of maximum growth of A. frigida was 20 times of L. chinensis, 4.8 times of S. grand/s and 39 times of A. michnoi. The life forms of L. chinensis, S. grandis and A. frigida were different, and their growth rates and growing curves were also different greatly. However the life form of A. michnoi and L. chinensis were same , and their growth rate showed the little difference with the maximum growth rate of L. chinensis being 1.9 times of that of A. michnoi. Also the two plants showed the similar growth dynamic in one growing season.