丹参根部生长规律Logistic模型研究

Growth Rhythm Logistic Model of Salvia Miltiorrhiza Bunge Root Traits

通过Logistic方程以定植时间为自变量建立丹参(Salvia miltiorrhiza Bunge)主根粗、主根长和根鲜重的生长模型。分别用2011和2012年的数据进行拟合和检验,用1∶1作图法(1∶1plot)和均方根误差(RMSE)与实测值进行比较。通过对Logistic方程求一、二、三阶导数和拐点,研究了丹参根部生长速率与密度和氮肥的关系,探索丹参根部的生长规律。2011年拟合方程的决定系数均达到0.96以上,回归方程统计检验均达到极显著水平(P<0.01);2012年拟合方程的决定系数均达到0.95以上。结果表明,用Logistic曲线可较好地拟合丹参根部生长量与定植时间的关系;在生长中期和后期,低密度(株距25 cm×行距30 cm)处理的丹参根鲜重增长速率比其余密度处理的快;适量的氮肥(100 kg/hm2)使根鲜重的增长速率较快且持续的时间较长,速生期是丹参根部生长的关键时期。

Using planting time as independent variable, the growth models of root diameter, root length and root fresh weight Salvia miltiorrhiza Bunge by Logistic equation were established. The data of 2011 and 2012 were used to fit and validate the models separately. 1：1 plot and root mean squared error （RMSE﹚ was used to compare simulated values with observed values. The first, second and third derivative and inflection points of logistic equation were used to analyse the relation of the growth rate of root fresh weight to the planting density and nitrogenous fertilizer and the growing trend of root traits of S. miltior-rhiza. The determined coefficient（R2﹚ of the data of 2011 were above 0.96 and reached significant levels（P〈0.01﹚. The deter-mined coefficient（R2﹚ of simulated values and observed values of 2012 were above 0.95. Results showed that there were high consistence between the growth of root traits and Logistic curve fitting. The growth rate of root fresh weight of lower density treatment was faster than that of the higher density treatment in the middle and late growth. The moderate nitrogenous fertil-izer （100 kg/hm2﹚ made the growth rate faster and the growth time longer. Fast-growing period of root traits of S. miltiorrhiza was very important time.